28 April 2022

Le temps qui passe

It's funny, but at the end of every day, I inevitably feel like the time has passed without me getting anything done. But when I sit down to write this blog, and list the tasks we finished, I find we got a lot done. However, as thrilling as these jobs are to talk about, it's currently late at night after a long day, so I'm just going to just bullet-list the day. I'm bushed!

First, we did something we've wanted to do for a long time, which is to confirm the size of each of our 4 water tanks. After rinsing out the anti-freeze, all 4 tanks were empty, so it was a great time to do this. We  did this by using a simple water-flow meter meant for gardening. Perhaps not surprisingly, our measurements did confirm, pretty closely, the figures we inherited from previous owners. So that's good. It also gave us some confidence in the inexpensive flow meter we used. We plan to use it to track the amount of water we put into our tanks, and to use another, slightly more sophisticated flow meter to track the water pumped out of the tanks. More on that later. BTW, our 4 built-in tanks hold 105 gallons.

Simple water meter, but pretty accurate!

Once the tanks were full, we tested all the work we did in the galley fresh water system. There was just one leak: one of the under-sink filter canisters was loose. I like to hand-tighten theses canisters, so they don't get stuck, but in this case, it needed another half-turn with the wrench.

Helena then prepped the bottom for painting. For this, she uses a purple 3M Scotch-Brite pad, which takes off just a bit of paint, without making a lot of dust. Many boat yards don't even allow sanding anymore, and let's face it, sanding bottom paint isn't the healthiest thing you can do. Using a wet scrubbing pad does the job without making any dust. Highly recommended.

Use the purple ones!

Meanwhile, I dug our Jordan Series Drogue out of a completely inaccessible locker in our fo'c'sle. We'd been storing it there because we'd never use it coastal sailing between the Bahamas and Maine, but if we ever are going to use it, it will be on a transatlantic passage. I had to completely empty one side of the fo'c'sle to reach the locker -- a job that took over an hour while on the hard. It confirmed my notion that it would be effectively impossible to get it out at sea, especially rough seas. It's now stowed in a much more accessible part of the fo'c'sle. 

I also opened up the sail kit for our new dingy, just to see what was in the box, and to retrieve the assembly instructions. Glad I did, because the instructions were missing (they are included in the instructions for building the boat itself, which I don't have at the moment.) A quick phone call to Chesapeake Light Craft (just down the road in Annapolis) and I received a copy of the instruction by email. Perfect.

We no longer try to replace parts in our manual toilet pump. It's much easier, and not much more expensive, to simply replace the whole pump assembly. Helena started this process today by removing the old pump, and I installed the new one.

Just replace the whole darn pump assembly!

Helena also started recharging all the many, many devices we have on the boat that have rechargeable batteries. They had been in storage all winter, and most needed a topping up. We have a long checklist of these devices so that we don't forget any. It's a pain, but it sure beats carrying a hundred pounds of disposable batteries!

While she did that, I investigated the remnants of the old saltwater water system. Petronella used to have a saltwater pump in the galley, like many blue water boats of the 60s and 70s, but at some point, someone disconnected it. No idea why, but I want to reconnect it. I made a plan of how to do so, which I will get into in much more detail when I actually go to install it.

So, not a bad day. Onwards!

Next Up:

27 April 2022

I started the day with 8 projects...

There's a famous old boatyard saying: "I started the day with 8 jobs to do. I finished 5 of them. Yay! Now I only have 12 left!"

This steady accretion of jobs happens for lots of reasons, most of them grim. But sometimes just by happenstance. In today's case, a job got added simply because the faucet I installed yesterday happened to come with a soap dispenser. Now, this is something I would never buy for a boat, but as I was about to toss it into the trash with the faucet box, I thought, "Well, why not?"

Soap dispenser installed

Of course I didn't have the right size hole saw (it doesn't seem to matter how many I collect. There's always one I don't have), so I had to make a quick run to the hardware store, but otherwise it was a nice simple install, and I think it will be a handy addition to the galley. We can dispense with the pump bottle held in place by the piece of bungie cord that we inherited from John & Gill. Nice.

On the grim side of the ledger, I discovered that one of the sink drains was leaking. Turned out to be a (very) old hose clamp that just wasn't doing its job right. The clamp was completely corroded so I couldn't even loosen it to get it off. Luckily there was enough room on the hose to fit another one. Second extra job done. 

Extra hose on left-hand drain pipe to stop leak

You might think it's odd that I'm spending so much time on the water system, but if you think about it, there are only a few things that really need to work to get across an ocean: keep the water out, keep the rig up and sail driving, stay on the boat, and make sure you don't run out of water. Food too, but mainly water. 

Continuing on this fascinating topic, it was nearly time to commission the water system after the winter lay up. This means flushing the anti-freeze out of our four water tanks. Luckily, I was able rope Helena into doing this job: put 5 liters of water into each tank, pump it out, repeat until the water runs clear.

When that was done, I had to replace our two under-sink water filters for the season. Having completely re-built this filter system a couple of years ago, it's a relatively easy job. I use a 20 micron coarse filter, followed by a 5 micron carbon filter for taste. We also filter the water on the way into the tank, so the hundred gallons of water we carry on Petronella tastes great right out of the faucet. 

The main trick I have to share about our water filters is to coat the threads with a bit of silicon paste. And to change the filters every 3 months. Also, only hand-tighten the filter cases. The biggest problem I've had with this system is having the filter cases freeze shut. I dislike working with my head under the sink, so I try to keep the filters easy and fast to replace.

Under sink water filters

Coating the case threads and o-ring with silicon goop, 
to make it easy for future-you to get them off again.

Meanwhile, Helena was hard at work removing the calcium from our many zinc anodes. She does this with a round-brass brush and a hand-drill. I won't say it's fast or pleasant work, but it needs to be done.

Helena doing cleaning zincs. Eye and dust protection a must!

But she's not the only one with nasty jobs to do. I was still thinking about water, this time, black water. The sending unit on our holding tank stopped working towards the end of last season. It seems to be an electronic problem, because cleaning it didn't help. There's no way to fix it, so I need to find a replacement. I will spare you the gritty details, but this is what the top of the sending unit looks like. What is a sending unit, you ask? It's the thing that tells you your holding tank is full. Yup. "Real boater stuff"™. 

Sending unit with green tape. 

I had to measure the size of the hole in the top of the tank, the tank thickness, and other details I might need to find another sending unit. 

Finally, I had to run to Chesapeake Light Craft to pick up the sail kit for our new dingy, an Eastport Nesting Pram. I've rented a storage unit that I will use to build the kit. Hopefully we will have a few days relaxation before departure to try out this cute little sailing dink. 

And that was another day.

In The (Work) Groove

 If you read my last post, it probably sounded like we were already in the work groove, but not really. It is a big change from wintering in France, where the biggest problem I have is being prepared enough in French so that my two French teachers aren't embarrassed for me, to getting up early and just working on a very cramped, very crowded, and disorganized sailboat. 

However, after a couple of days, the mind adapts. People can get used to just about anything. You just need to give it some time.

Here's an interesting problem: when you have a whole list of jobs, which do you do first?

I have two answers to this problem: First, focus on jobs that must are done before other jobs can be done. For example, ordering parts. Can't do the job until the parts come in, which can sometimes take time. Second, work on below-deck jobs before above-deck jobs. The reason for this rule is that as long as you are working below deck the boat is likely to be unlivable, or nearly so. The sooner we get the below-deck jobs done, the sooner we can be comfortable down below. 

At the moment, I am focusing on our water system. First up, I finished replacing the valve that controls water from one of our tanks. That was probably the most important repair I had on my list, so naturally it was the first to be done.

Water valve repaired... much easier than I anticipated.

Another important project is to install a saltwater pump in the galley, so that we can easily use salt water for washing dishes, etc. To do that, I first had to replace our ancient galley faucet. This faucet was so old that every moving part was frozen solid with corrosion. Both valves were stuck solid, and even the faucet itself was frozen in place, which was really inconvenient. 

It was a pretty big job, mainly because the sink wasn't plumbed for a modern faucet. The hole in the counter top was too small, and the water feed lines (as you can see) were not exactly up to modern standards. Basically, the fresh water feed line was a 3/8" I.D. water hose, which meant I needed to buy the correct adapters.

If you've ever tried to make a hole made by a hole saw larger, you know this is a tricky job. A hole saw has a pilot drill bit that needs to bite on wood to keep the main body of the hole saw steady. If you've already got a 3/4" hole which needs expanding, there is nothing for the drill bit to drill into. 

Hole saw... needs wood for the pilot drill to drill into

Solution? I glued a small piece of plywood underneath the counter, which covered the hole. That gave the drill bit something to drill into, and stabilizing the hole saw enough to make a clean cut and expand the hole to 1 3/8". 

For adapters, I found a 3/8" male compression to 3/8" pipe fitting adapter, and a 3/8" pipe fitting to 3/8" hose barb adapter, and that adapted the compression fitting on the faucet water line to the water hose under the sink. 

And, voila, a new faucet with actual working parts!

New faucet installed.

I plan on using the hot water line for salt water. That's why I needed two working valves: the cold for fresh water from the tanks, and the hot for salt water from the ocean. 

Plumbing in a salt water line is going to be another whole-day project which I will tackle in the next day or two. I also want to install a flow meter on the fresh water line, so we can measure how much water we've taken out of the fresh water tanks. The reason for doing that should be fairly obvious when one is crossing an ocean!

That's it for now. Back to Petronella and today's jobs!

Next Up: I started the day with 8 projects...

22 April 2022

Back in Annapolis!

So, I'm here to tell you that it is NOT easy to leave the south of France in the spring time. The weather is perfect, our (current) favorite restaurant has out door tables under beautiful shade trees, with an old fountain bubbling away, and the view of the Église Saint-Roch a bit of perfection. 

Not easy to give up!

However, if we are going to cross the Atlantic this summer (and that's the plan), we had to say goodbye to our French and expat friends in Montpellier, and head back to Annapolis to get ready. 

It seems like every year, our insurance company wants some sort of survey or inspection, and this year was no different. They wanted a full insurance survey, and a rig inspection. So our first morning back we had no time for the normal indulgence of jet lag and homecoming celebrations. We had to head right back to Petronella to give her a quick tidy, and then greet the surveyor at 9 am. I spent most of the day with him, but in the meantime, Helena tackled the first couple of jobs on our to-do list.

First up was to empty the bilge of whatever water had gotten in. How it gets in is a bit of a mystery, frankly. Condensation? A small leak in the deck somewhere? I have no idea. But over the course of the winter, a couple of cups of water plus a bit of oil got into the bilge. Helena got it out.

Meanwhile, I'd discovered that one of the connections to our solar panels was intermittent, so I cleaned all the connections with terminal cleaner. A must-have tool for debugging solar panel problems, as well as other electrical problems, is a clamp-on ammeter. Being able to see the amps being put out on the wire going to the battery made it easy to track down the bad connection. However, since I was there with all the tools and spray, I cleaned all the connections, just to avoid problems down the line.

Solar panel wiring and connections

A clamp-on meter is essential for debugging electrics

By then, Helena was onto her second job of the day, caulking this sink. This is another job she does every spring, since she has a mild obsession with caulking and nice white lines. It needs to be done before we commission the sink and water tanks, so it's a job that she tackles right away.

When the surveyor left (everything seemed to go well, but still waiting for the report), I got onto my big job of the day -- replacing a broken valve in our water system.

We have three main water tanks on Petronella, and each tank has a valve which allows us to choose from which tank we are drawing water. Unfortunately one of the valves broke last summer, making it impossible to close off that tank. That made it very difficult to know exactly how much water was left in each tank. Clearly not acceptable for the crossing, so a high-priority job.

Plumbing is not my favorite pastime, but I'm getting better at it. In particular, I find getting reinforced plastic hose off of whatever connector it's stuck to can be a very frustrating job. However, I have learned the trick of using a heat gun to soften up the plastic a bit after removing the hose clamp. This makes it much easier to remove the hose. I had the hose off and valve unscrewed from the system so fast, I forgot to take a 'before' picture. This is the 'after' picture, with the valve removed.  

The under-sink set of valves and hoses to various tanks.

The broken 3/8" valve with hose barb still attached

It should be easy to find a replacement valve tomorrow and have the water system ready to go by the weekend.

Finally, Helena and I met on the bow to measure for a triangular-shaped, rain water-catching awning. When rigged, this will fill the entire bow-triangle, from the main mast shrouds to the forestay. However, I want to be able to easily move under the awing when it is raised -- to get to the anchor, for instance -- so I decided to position the awing about 68" above the deck. At that level, the distance between the port and starboard shrouds is 75 inches, and from each shroud to the forestay about 126 inches. A bit of math shows that this will give us a collector of about 60 square feet. 

Bow water collector measurements

Like lots of others, we've used our cockpit awning as a water collector for years, however, I've never been thrilled with it. The main problem is that a cockpit awning is up nearly all the time. This means it gets pretty dirty. That's fine for collecting shower water, but not drinking water. Not for me, anyway.

I plan to build our collector out of untreated, natural cotton duck (canvas), and only rig it when I think we are going to get some rain. This will keep it clean and out of the normal range of cormorants and other nasty birds. I considered using Sunbrella, but the manufacturer warned me off. Sunbrella is treated with lots of interesting chemicals to make it waterproof and mildew resistant, and thus it is not recommended for collecting drinking water. We will have to be more careful to dry untreated canvas before stowing it away, but this shouldn't be a big problem in summer cruising conditions. 

So that was our first day back. We've got 40 more days to complete our prep. Finger's crossed we don't run into any big problems in the meantime!

I will try to post often now, to track our preparation progress, and to give you an idea of what kind of prep we do before launching. It should be good fun so check back often.

Next Up: In the (work) groove

30 March 2022

Displaying Pilot Charts in the qtVlm Charting App

Last time I promised to blog about something I've wanted to do for a long time, which is to display pilot charts in an iPad charting app, like qtVlm. My primary reason for writing this blog is to make sure I don't forget how to do something after I've taken a long time to figure it out. Alas, I waited too long to write this post! I've actually forgotten how I did it, so will have to figure it out again, this time writing down the procedure as I go. 

So, let's go.

Pilot charts are used as passage planning tools. Much of the information contained on pilot charts stems from the shipmasters’ log-books kept by the 19th century Lieutenant Matthew Fontaine Maury of the US Navy. He earned the title of the ‘Pathfinder of the Seas’ for his study of ship routes and logbooks. 


As we saw last time, it's relatively easy to plonk an image into qtVlm and georeference it. This is what I did with my first attempt to solve this problem: just grab the PDFs of the pilot charts that anyone can download from National Geospatial-Intelligence Agency. Alas, these downloadable PDFs are not high-resolution enough. They load fine, but the low resolution makes them look very fuzzy on the screen. This stumped me for quite a while, until I discovered a trove of high-resolution pilot charts created by the OpenCPN team. These are not just PDF files, but real electronic charts in BSB ver2 raster chart format. You can see the complete list of pilot charts on the OpenCPN website

If you click on the link for the Central North Atlantic charts, you will download a file called NAC.7z. Yeah, I was scratching my head too. What is a 7z file? The 'z' should have been a tip-off. It's a type of zip file. In other words, a set of files that have been bundled together and compressed to minimize size.

I assumed the set of files was the set of pilot charts, one for each month of the year. But how to download and extract them on an iPad? Not so easy.

The first thing you need is an iPad app that can unzip 7z files. There are several, but I used iZip. So if you want to follow along, go to the App Store and install the iZip app

Once you've done this, downloading the 7z file *is* fairly easy. Just use Safari on your iPad to go to this OpenCPN web page, scroll down a bit, and click on the part of the world you are interested in, like the Central North Atlantic. You will get a pop-up asking "Do you want to download "NAC.7z"? Just click the 'Download' button and the download will commence.

When the download is complete, click on the 'show downloads' button in the Safari tool bar. It should be just to the right of the address bar, unless you've rearranged things. It looks like a down-arrow inside a circle.

The file you've just downloaded should be in the dropdown. In my case NAC (for North Atlantic Central.) Click on this filename, and the iZip app should open up automatically. If not, just select it from the list of apps that can handle 7z files (you have more than one???) It will ask "Would you like to unzip all files?" Click the OK button.

The unzip process should only take a few seconds on a modern iPad. When it finishes, click on the "Back" button.

You should then see two things: the NAC.7z compressed folder, and the NAC uncompressed folder. If you click on NAC folder, you will see all 12 charts, labeled NAC01.kap, NAC02.kap, etc.

Now we just need to load these chart files into qtVlm. Assuming you already have qtVlm installed, this is easy. Just select the charts you want -- I just selected all of them -- and then click the 'Share' button below the list of charts. 

You will get a pop-up asking you if you want to compress the files. Say 'No'.

You will then get another pop-up showing Apps which can accept the .kap files, including qtVlm. Just click on the qtVlm icon. 

That's it! The pilot charts are now available inside qtVlm. 


So, how do you choose a chart to display in qtVlm? This is so easy I will just give you the procedure:

  1. Open qtVlm
  2. Click on the Menu icon, in the bottom-right corner of the screen - this will open the menu
  3. Click on "View" menu option
  4. Click on "Single chart"
  5. Click on "Open a chart" - this will open the Chart window.
  6. Click on the "Browse" button - this will display a list of folders
  7. Click on the "kaps" folder (where all .kap files are stored, like the one's we just installed)
  8. Click on the pilot chart you wish to view, for example the June pilot chart - NAC06.kap
  9. Click the OK button at the bottom of the screen (you might need to scroll down)
  10. Click the OK button at the bottom of the Chart window. 
Voilà, the June pilot chart should be displayed in its correct position on the globe. Kap files are already geo-referenced, so there is no need to fiddle around with them. 

To display the July chart, just go back to the Menu and follow the procedure above to load NAC07.kap. Once you get the hang of it, it only takes a few seconds to switch charts.

In the image below, I've zoomed the chart display out far enough to display the whole pilot chart. You can see that it is geo-referenced perfectly. That is, it is displayed in the correct location in the chart display. Of course, in real life, we would be zoomed in on a certain area of the chart, like in the next image.

Pilot chart displayed in qtVlm

You can even use a pilot chart as a base map, displaying GRIB data and weather charts over it. 

For example, here is the June NAC chart with GRIB data showing the Gulf Stream layered over it. 

 Using a pilot chart as a base map, with GRIB data layered over it.

I think this is an amazing tool for both planning passages, both before and during the passage. Let me know what you think in the comments below!

Next Up: Back In Annapolis

23 February 2022

Layering GRIB Data over the Weather Chart

Note: if you have gotten this far but are muttering to yourself, "Gosh, this looks like a lot of work!", I encourage you to work through the examples for yourself. Once you get the hang of it, you can update the charts and GRIB file in qtVlm in under a minute. 95% of the work is in georeferencing the charts for the first time, which you can (and should) do at home. Once they are set up, doing updates is easy. Really! And so worth the effort.

Last time, we talked about how to georeference weather charts and display them using qtVlm. Now we get to do the easy part, which is to layer GRIB data over those charts in a way that allows you to see a much better picture of the weather forecast than using either product alone. I plan to update both weather charts and GRIB data at least once a day on our planned Atlantic passage.

Coastal sailors used to downloading several megabits of GRIB data using their cell phones will have to learn to trim their data habit down to size. Even with an unlimited satellite plan, you don't want to be downloading megabits of data. With big downloads, the connection will drop multiple times, forcing you to retry the download over and over. It's a big pain, so I try to download just the data I really need. Luckily, qtVlm makes this very easy.

So, what data do we really need? I plan to use the GRIB data for both weather forecasting and for weather routing. So I plan on downloading the GRIB data for the 'corridor' that includes all the possible routes I might take in the next week or so. 

For example, I don't plan on sailing too far north of 40°N when sailing from the Chesapeake Bay in the US to the Azores. So for the first week of sailing, I will choose an area between, say 35°N and 45°N, from the US East Coast to about half-way to the Azores, or 40°W.

But actually, I will choose this corridor graphically, using the square 'Selection' tool in the qtVlm tool bar.

Selecting area for GRIB data graphically
The steps are (see image above):
  • click the Selection tool in the tool bar
  • click and drag to select the area you want to fill with GRIB data
  • click the Menu button in the lower right corner
  • click 'Grib Saildocs' menu item
  • select Grib parameters
  • scroll down and click 'Send Email' button

Specifying as small a GRIB file as possible

Clicking 'Send Email' will generate the request in either your normal Mail program, or in Iridium Go mail, depending on whether you are experimenting at home or working at sea. You can choose which type of email to use in the qtVlm Configuration. 

After you send your Grib request, you will receive the data back by email. It is then easy to load the data into qtVlm. Just click on the data icon at the bottom of the email, and you will be given a selection of apps which can load the data. Choose qtVlm. It's that easy. 

Choosing the right GRIB date for the
right weather chart

Once you load the GRIB data from the email, it will be displayed in qtVlm. Since the Grib data is already georeferenced, there are no extra steps to do to position it on the chart.

However, there is one more very important step (you knew it, right?) 

A weather chart, such as the 24-Hour Surface Forecast chart, is drawn to forecast the weather at a specific date and time. In the image above, it's for 24 Feb 2022, at 00:00 UTC. 

To properly overlay the GRIB data on this chart, you must set the GRIB date to be the same as for the chart. This is done using the 'Select Grib Date' tool on the tool bar. It looks like a clock. To set the Grib date, you click on this tool, and use the date selector dialog box to choose the same date and time as the chart. I've already done that for the image above. You can see the current Grib date/time in the upper-left corner: "Thu 02/24/2022 00:00 UTC" -- the same as for the Valid time on the weather chart.

Once you do this, you will have the weather forecast chart, and the Grib data for that chart at the same time. You can see the strong winds circulating counter-clockwise around the "Developing Storm" over Labrador, the two nasty-looking cold fronts off New England, as well as the high pressure area coming in from off of Florida, and the winds circling clockwise around a high which is off the screen to the right. 

The weather chart gives you the Big Picture which puts the Grib data into a bigger context, which makes it easier to understand, I believe. Look at the Grib Data alone for the 48-hour forecast, without the 48-hour forecast weather chart behind it:

Grib data alone for the 48-hour forecast

If you are used to looking at weather charts, it's probably clear that the storm has moved off to the east, and maybe the high that was off Florida has moved north, but if you are used to just looking at GRIB data alone, you might be pretty vague about what else is going on here. Like the nasty cold front that you definitely want to know about. 

Look at the same data with the 48-hour Forecast chart behind it:

48-hour Grib with 48-hour forecast chart

There is just so much more context for the Grib data, that makes it easier to understand, I think. It's this big-picture context that weather charts provide that make this exercise worth-while, if not essential. 

And the benefit goes both ways. If the weather charts provide the big picture, the Grib data allows you to see what is forecast between the forecasts. You can step through the Grib data hour-by-hour in the usual way to have the convenient, continuous forecast that Grib provides. I believe that viewing charts and Grib data together like this gives you the best of both worlds. I am utterly thrilled that qtVlm finally allows me to view this kind of comprehensive weather forecast on my iPad. Fantastic!

Well, that just about wraps up the longest blog post I've done in all 12 years of writing these posts, but I personally think it's one of the most useful I've ever done, at least if you are interested in crossing oceans. I can see from my web stats that only about 75 readers have stuck with me through this discussion, so if you're one of the 75, congratulations! I'd be interested in hearing your thoughts and ideas.

Actually, I have one more closely related post to do on this subject. Something I've also wanted to do for a long time, which is to display pilot charts on a charting app like qtVlm. I've JUST figured out how to do that, so that's what we will talk about next time.

À bientôt from the sunny south of France!

Next Up: Displaying Pilot Charts in qtVlm Chart Plotter

17 February 2022

Georeferencing weather charts using qtVlm

Last time, we started talking about how to view both weather charts and GRIB data simultaneously. If you installed qtVlm and downloaded the weather info as described in that post, you will be able to follow along with me.

So, the first problem we need to look at is, how to load a weather chart (that we've downloaded via email or weather fax) into qtVlm. To do this, we need to tell qtVlm what part of the planet the chart covers. This process is called georeferencing. Most charting programs can't do this, and that's what makes qtVlm useful for this job.

We need to make a couple of assumptions to keep the length of this post somewhat reasonable: 
  • I will be using an iPad for my examples, but the techniques are nearly the same on a Mac and quite similar on PC or other tablet, but I won't be discussing those variations here.
  • I will be using email for downloading weather charts and GRIB data. There are other ways to obtain exactly the same data at sea, but those methods are out of the scope of this discussion.
Step 1 - Save weather chart to Photos

After we've downloaded the weather charts using email, we need to save them to the Photos app for two reasons:
  • some of the charts need to be rotated into the north-up position before they can be used
  • qtVlm can access the charts once they are in Photos
Any email program on the iPad can save an image into Photos using the share button. In the normal iPad Mail app, there is the share button at the top of the screen. In the Iridium Mail app, there is a text button at the bottom of the screen.

Share button on iOS Mail app
Select 'Save Image'

Share button on Iridium Mail app
Select 'Add to Shared Album'

Once the chart is in Photos, you can rotate it if necessary to orient it so that it is north-up. For example, the chart in the image above is east-up, and will need to be rotated.

Note: for some reason, the Iridium Mail app can only save an image to a Shared Album in Photos. Unfortunately, you can't rotate an image that is just in a shared album. So you need to add the following steps:
  • Go to the shared album you've saved the chart to (I use one I created called Weather Charts)
  • Open the image
  • Click the share button, and choose 'Save Image'
This will save the image to the normal Photos library. 

Step 2 - Rotate if necessary

If a chart is not oriented north-up, you need to open the image in Photos and use the Edit tool to rotate it into the correct orientation:
  • open the image in Photos
  • click the Edit button in the upper right-hand corner
  • click the crop and rotate button on the left side
  • click the rotate button at the top of the screen enough times that the image is north-up
For example, here is the Western Atlantic Surface Analysis chart after being rotated into the north-up orientation in Photos.

The Edit screen in Photos
(after clicking the Edit button in the upper-right corner.)

Step 3 - Load a chart into qtVlm

For this discussion, let's assume we are working on the Western Atlantic Surface Analysis chart, PYAA12.TIF. We assume the chart image has been downloaded, saved to Photos, and rotated into the north-up orientation. 

The steps to load the chart into qtVlm are:
  • Open qtVlm on your iPad
  • Click the menu button in the lower-right corner of the app
  • Choose the Grib menu option
  • Choose the Weather images option
  • Choose the Open a weather image option
  • Choose the Weather image configuration 1 tab on the pop-up window
  • Click the Gallery button and a list of photos will be displayed
  • Choose the correctly rotated PYAA12.TIF image
qtVlm can hold up to 8 different weather charts. You want to be consistent in which chart goes into which configuration. For example, for an Atlantic crossing, it makes sense to always put PYAA12.TIF into Configuration 1. If you do so, you will only need to go through the following Georeferencing steps once for each chart.

Step 4 - Georeference the chart

The chart image is now loaded into qtVlm, but the program has no idea how big the chart is, or where to place it on the globe. We need to tell it two things:
  • The latitude and longitude of the chart's upper-left corner
  • How 'big' the chart is, in terms of degrees of latitude and longitude
However, if you click the chart below to view it full size, you can only estimate the latitude and longitude of the upper-left corner of the chart. It is roughly 65°N, 100°W, but that is good enough to get us going.

Similarly, we can only estimate the width of the chart in degrees longitude, and the height of the chart in degrees latitude. Roughly, they are Longitude: 57°, Latitude: 50°.

Chart PYAA12.TIF

The steps to georeference a chart in qtVlm are:
  • Estimate the latitude and longitude of the upper-left corner of the chart
  • Enter these numbers in the Left Corner Position of the Weather Image Configuration tab. Be sure to choose the North and West options
  • Estimate the width of the chart in degrees of longitude
  • Estimate the height of the chart in degrees of latitude
  • Enter these number in the Longitude and Latitude Range fields.
  • Click the Activate button in the upper-left corner of the configuration tab
  • Set the Transparency slider to about mid position.
  • Click the OK button at the bottom of the configuration pop up window. You may need to scroll down to see it.

Georeferencing the chart using the 
Weather image configuration tab

After clicking the OK button to activate the weather chart, you should see the chart displayed in qtVlm in roughly the correct position. If not, you have made a mistake, most likely you have forgotten to click the 'West' button in setting the Left Corner Position. At least, that's the mistake I make most often!

Georeferenced chart in position

Note that the transparency setting on the image allow you to see the base chart underneath the weather chart. Probably your chart isn't lined up perfectly. You will need to tweak the Left Corner position and Range values until the weather charts lines up perfectly (more or less!) with the base chart. 

The steps for tweaking the geo-positioning values are:
  • Using the north-most and west-west most latitude and longitude lines on the weather chart, tweak the Left corner position values until the lines on the weather chart line up with the lines on the base chart. You will have to move the image on the screen until these lines line up roughly, then tweak the values.
  • Do the same thing with the lower-right corner of the chart, using the Range values
  • Repeat until the chart is 'good enough'. 
This is a tricky process the first time, but once you get the hang of it, it goes fast.

Here is what I mean by lining up the latitude and longitude lines of the chart and base map. You will have to move the chart around on the screen until the lines roughly line up. For example, here I have lined up the 60N and 80W lines. If you view the image below full screen, you can just about see the number on the base chart at the top and left sides of the chart. 

Note that the image below shows the lines after the Left corner position has been tweaked into position. Before tweeking, the lines do not line up perfectly. 

Using the latitude and longitude lines on
both charts to zero in on the Left corner position

If you are still with me, and have followed along, you no doubt are saying, "Well that was a pain!" 

The good news is that you only need to do this once for each different chart. The next time you load the same chart into the same configuration tab,  it can use the same georeferencing values. 

I will list the geo-referencing values that work for me on my iPad below. You would think the same values would work on every copy of qtVlm, but I found that the values needed for my iPad were not the same as those needed for qtVlm on my MacBook. I have no idea why this is, but intend to query the developers on this. They should be the same, I think!

Anyway, I have to assume that you will have to also tweak the georeferencing values for your machine, so I have given you the full process. It may be that the values I used on my iPad will work perfectly on your iPad, so I will list them below. They will at least get you close.

Western Atlantic Surface Analysis - PYAA12.TIF
    Left corner position: 
        65° 0.0'N    100° 15.0'W
        57.7° Long
        50.77° Lat

Easter Atlantic Surface Analysis - PYAA11.TIF
    Left corner position: 
        65° 4.0'N    50° 20.0'W
        58.0° Long
        50.91° Lat

24-Hour Surface Forecast - PPAE00.TIF
    Left corner position: 
        51° 0.0'N    99° 55.0'W
        61.9° Long
        31.5° Lat

48-Hour Surface Forecast - QDTM85.TIF
    Left corner position: 
        64° 0.0'N    98° 24.0'W
        109.72° Long
        50.33° Lat

Okay! That's enough for today. Congrats if you have followed along up to here. This is advanced weather stuff! Next time we will overlay GRIB data onto these weather charts.

Next Up: Layering GRIB data over weather charts

10 February 2022

Combining GRIB Data and Weather Charts with qtVlm

At this point in our sailing career, Helena and I have accumulated quite a few offshore miles on Petronella, including two week-long passages up the east coast of the US. Anyone who does this much sailing is likely to take a passionate interest in the weather, and I'm no exception. It helps me anticipate how much wind we are going to have (typically, not enough!), where it will be coming from (typically, on the nose, or dead aft!), what's the best course to steer for where we are going (weather routing), and very occasionally, when to get ready for nasty weather. 

Many people these days depend on GRIB data as their primary or even sole source of weather information. It's easy to get, easy to interpret, and seemingly precise. For local sailing, I do the same thing. For example, when we are in Maine, I love to download the HRRR model data using my favorite weather app, LuckGrib, because it tells me if there is going to be fog that day, and where it will be. It's not perfect at this, but it's darn good.

On long offshore passages, I want more information. In particular, I want good, old-fashioned weather charts. We used to get these via weather fax, but these days it's much easier to get them via email using our Iridium Go. Weather charts give you the 'big picture': the highs, lows and fronts that are the stars in the majestic ballet of large scale weather systems. While it's possible to look at GRIB data displays and guess where these are, as an amateur, I would prefer to have this kind of analysis done by actual weather scientists. This is what the guys and gals at NOAA do every day, and one of their primary work products are these weather charts which are updated and published 4 times a day. It's just silly, in my opinion, to ignore these amazing weather products while at sea.

48 hour forecast chart. Click to view full-size.

Once you have both weather charts and GRIB data in hand, it's fairly easy to compare them side by side, but I've long wanted to somehow overlay the GRIB data onto the weather charts. This has been possible to do for a long time with the desktop navigation program called OpenCPN, but I don't like using my MacBook Pro at sea. I don't have a good place to use it, really, and I'm always afraid it is going to fly across the cabin and splinter into a thousand pieces. I prefer to use my iPad. If it's rough, I can curl up in a bunk with a lee cloth and do my navigation and weather forecasting in comfort and safety. But until recently, I didn't know of any app that could layer weather charts and GRIB data on the same screen. 

Enter qtVlm. This is an amazing navigation program that seemingly aims to do it all. It is loaded with features, but I'm just going to focus on one of these: the ability to display weather charts and GRIB data simultaneously. Spoiler alert: the result is just as great as I always hoped it would be.

First, what data do you need, and how can you get it? The basics are:

  • Weather analysis chart showing the current weather, plus forecast charts for 24, 48, and possibly 72 and 96 hours in the future. In practice, I tend to use just the 24 and 48 hour forecasts unless I am worried a special weather event is on its way. 
  • The high-seas text forecast which is basically a explanation of the weather charts written by the forecasters who create them
  • GRIB data for the area to be sailed in the next week or so.
There are lots of ways to obtain this data, but if you have an Iridium Go, or other satellite connection, you can get it by email, using the amazing saildocs service. You can try it yourself by sending an email to query@saildocs.com, with the following copy-and-pasted into the body of the email:
send PYAA11.TIF
send PYAA12.TIF
send https://ocean.weather.gov/shtml/A_sfc_full_ocean.gif
send PPAE00.TIF
send QDTM85.TIF
send PPAK98.TIF
send PWAM99.TIF
send met.4
send met.2
Note that the last line is just one line starting with GFS and ending with HTSGW, although it wraps on this screen. It must all be on one line in your email. It must also be exactly as written, which is why I suggest you copy and paste it, rather than trying to type it into an email.

If you send this email, you will receive back the data we need for our discussion today:
  • PYAA11.TIF, the latest weather analysis chart for the eastern Atlantic
  • PYAA12.TIF, the latest weather analysis chart for the western Atlantic
  • A_sfc_full_ocean.gif, the latest weather analysis chart for the whole Atlantic
  • PPAE00.TIF, the 24 hour forecast chart for the whole Atlantic
  • QDTM85.TIF, the 48 hour forecast chart for the whole Atlantic
  • PPAK98.TIF, the 72 hour forecast chart for the whole Atlantic
  • PWAM99.TIF, the 96 hour forecast chart for the whole Atlantic
  • met.4, the latest weather discussion for Metarea 4, which covers the western Atlantic
  • met.2, the latest weather discussion for Metarea 2, which covers the eastern Atlantic
  • GRIB data for area likely to be sailed on a passage from the Chesapeake to the Azores
Out at sea, to save download time, I would request just the charts I needed for the day. Or maybe use my SSB to download them all as weather faxes, if propagation conditions were good. For more information on weather faxes, see my old blog post on this subject: Another look at weather faxes.

To follow along with this discussion, you will also need a copy of qtVlm on your PC, Mac, Linux, or Raspberry Pi computer, or an Android or iOS tablet. You can download the software for free from the qtVlm website, or from your App Store

Well, I can see this is going to be too long a discussion for one post, so I will stop here and let you install the software and experiment with saildocs. Next time, we will see how to view this data in qtVlm.

Next Up: Georeferencing Weather Charts

02 February 2022

Cabin Boy's European Adventure

Thanks to a gentle nudge from friend-of-the-blog Mark, I've decided to get off my duff and start writing again. It's been a long time!

Well, when we last met in the spring of 2020, the pandemic was just getting its nasty claws around our necks and starting to squeeze. We had to cancel our Atlantic crossing, and for a few months -- when boating was actually forbidden in the State of Maryland, remember that? -- we wondered if we'd even be able to launch Petronella. In the meantime, we built a new cockpit awning.

Stranded ashore? Might as well build a new cockpit awning.

With some nice details that would be very expensive to have done
like these toggles for the side panels. The benefit of having
nothing else to do!

Thankfully, restrictions loosened up by summer, and we were able to move out of our son's apartment, launch Petronella, and eventually cruise up to Maine, where all the traditional cruising meet-ups were canceled, but even waving to other cruisers from a distance is better than being land-locked all summer.

How to pick one picture from a whole summer in Maine?

We spent the winter of 2020-21 on a mooring in St. Augustine, FL, not a bad way to spend lockdown, actually, although again all the usual St. Augustine Cruiser's Net activities were canceled. I used the time to rebuild our old manual windlass. What a job!


During (but will I be able to put it back together?)


The summer of 2021 saw us back in Maine for more great cruising and hiking and, in retrospect, having all that extra time on Petronella was a blessing in disguise. We found and fixed a few more problems that would have caused real problems if they had revealed themselves during an Atlantic crossing. 

The first was with the chainplates which over the last 45 years had worn pretty thin. Problem was, the thinness was disguised by some Bondo and a lot of paint. Luckily, it occurred to me that it was pretty strange for them to be in such good condition after all that time, and I took a chipping hammer to the paint. Wow, was I surprised. We cut them off with a torch (sounds so simple, right? What a horrendous job!) and welded on some new stainless steel ones. They should be good for another 50 years.

Still strong, but pretty worn out chain plates. 
Note the pink Bondo filler. (Argh!)

The new chain plates with first coat of primer 
covering area of paint burned off by the torch.

We also discovered that the bearings in the U-joints on our driveshaft were worn and in danger of failing. Solution: a brand new drive shaft. The engine noises were cut dramatically by this change. What a relief.

Then on our way up to Maine last summer, the hinge which allows the rudder on our Aries wind vane to swing up broke with a loud Bang!, like a gun shot. I was amazed such a heavy piece of gear could crack in half like that, but apparently the hinge is a weak spot on all wind vanes. We bought a replacement from a company in the UK that still makes Aries parts and vanes.

Finally, our 4-year old Awgrip red paint was looking really sad. It had faded and looked blotchy and horrible. The Awlgrip rep down in St. Augustine was mystified, because the paint really should last 10 years. Well, there was nothing for it but to haul out and try again. Helena and I had watched the professionals roll-and-tip Petronella back in Norfolk, and frankly it hadn't looked like rocket science, so we did it ourselves, following the Awlgrip instructions to the letter. Fingers crossed, it will last longer this time.

Prematurely ugly paint job

After Helena and I rolled-and-tipped two
new coats of paint on. Note scaffolding which
is required for this type of work.

Note to self: If you want something done right...

Currently, we are back in beautiful Montpellier, France for the winter. Petronella is slumbering in Annapolis, MD. Come spring -- King Neptune and Covid permitting -- we will again try and cross the Atlantic via the Azores to Northern Europe.

We feel that Petronella is in great shape now and with a few thousand more offshore miles under our keel, we too are much more experienced and better prepared than we were two years ago. So, I guess you can say the pandemic did us some good, after all.

We are now gearing up again for the voyage and I have a lot of thoughts and plans I want to get down in writing. As usual, I do this mainly for our own use, but perhaps they will be useful or interesting to others who might be a bit behind us.

Really looking forward to the next big adventure!

With French friends in France

Next Up: Combining GRIB Data and Weather Charts using qtVlm