26 April 2020

A Chronometer for Celestial Navigation

Getting ready to cross an ocean is like running an obstacle course. At times, it seems like the number of hurdles is unlimited, and that you will never get over all of them. But if you persist, eventually the 'must do' hurdles thin out and the ones that are left are all marked 'nice to have'. You start to think, "Hey, this might really happen!"

Of course, last minute problems are sure to crop up. For example, our insurance company decided we needed to have an engine survey. Our ancient Mercedes OM-616 checked out fine, but the surveyor discovered that one of the universal joints in Petronella's drive shaft needed repair: the needle bearings were worn. I thought we might have to cut a hole in the side to get the drive shaft out, but Cobbs Marina figured out a way to extract it without major surgery. Great job, guys. Nothing is going to stop us now!

And then, oh whoops. The Azores is closed? Spain is closed? France is closed?

So, like many other cruisers, we've postponed our Atlantic crossing until next May. I won't pretend it isn't a disappointment, but the delay does give me time to document some of the things I've been working on, so I don't forget them by next year when I will need them again.

Speaking of time...

The whole crew (me, Helena, and our wonderful French friend, Eleonore) were all looking forward to navigating across using celestial navigation. There are a dozen GPSs on Petronella, including phone, iPads, VHF handhelds, etc., so we would have one if we needed it, but we were going to try to find the Azores using dead reckoning and fixes using celestial navigation, just for fun.

Helena and I had been brushing up on our calculations, I'd refurbished my 70 year old bronze sextant,  and I had paper charts of the Atlantic. But you need more than charts, and a sextant, and tables to do celestial. For dead reckoning you need a log to measure distance traveled through the water (solved, with a Walker trailing log found on eBay), and you need a chronometer.

Walker Trailing Log
Why do you need a chronometer? In short, because when you take a sight with your sextant, you need to know the exact time of the shot. Every second your chronometer is off puts your fix off by 1/4 mile, and even a good watch can be off by 10 or 20 seconds in the month it might take for a crossing. You want to do better than that, so instead of an ordinary watch, you want to use a chronometer.

What is a chronometer? In a nutshell, it is any clock or watch with a known rate of error. It's a lot like a magnetic compass: to get an accurate reading from a compass, you need both the compass and its deviation table to correct for the known compass error.

A chronometer is simply a watch with a 'deviation table' which will correct for the known watch error.
Compass Deviation Table
So, our job is to first figure out what the error rate is for our watch, and then to create a 'deviation table' to correct that error. Actually, for two watches, in case the first one dies during the trip. And for fun I rated Petronella's ship's clock.

I got the idea for how to do this from David Burch's blog post, Finding Watch Rate. However, at this point, I think I've spent more time on this than he did, so I have a few ideas to add to his excellent post.

The basic procedure is:

1. To set each watch to the exact time, or as exact as you can make it.

2. Every couple of days, you check the watches against a known accurate source, and record the observed errors.

3. Once you have a month's worth of errors, you can create a deviation or 'watch error correction table' which will allow you to correct your watch to within 1 second's accuracy.


Consult your watch manual to determine how to set it. I had no problem setting my two Casio watches to the exact time, but for some reason, the best I could do with my ship's clock was 1 second off. This doesn't matter, as we shall see, so don't sweat it if you can't get your watch set exactly right.


To rate a watch, you need an accurate reference time, and you need some way to capture the watch error accurately.

The Internet's NTP system provides an excellent reference time which means you can use just about any computer or mobile phone as a reference clock, accurate to about 100 ms.

David had the great idea of using a photograph to capture watch errors accurately by arranging the watches we are rating next to the reference clock, and taking a photo of all of them together.

He used an Apple Watch as his reference clock, but I used an iPhone (far right in the photo below) running the appropriately named Time App. Because the Time App displays Internet Time to a 10th of a second, it eliminates the need to average several reading to get an accurate error rate. All you need to do is take a series of photos until you capture one with the 10ths digit reading zero.

Two watches, ship's clock, and reference time.
Once you snap the right photo, you can record the exact time of the photo, and the watch errors for each watch. Do this every few days for about a month, and you will end up with a table like that below:

Click for full size

The data fields for this table are;

Date: date of reading
DOY: the Day of Year, from 1-365 or 366 in leap years.
Hr: Hour reading was taken
Min: Minute reading was taken
d.dd: Decimal date of reading  = DOY+(Hr+(Min÷60))÷24
dT: decimal time since setting = current d.dd - d.dd of setting
WE: watch error reading. Negative if fast, positive if slow
1d rate: error rate per day in seconds. = (current WE - original WE)÷dT


The calculation for Watch Error (WE) is pretty simple:

            WE = number of days since setting * 1-day error rate

Our ultimate goal is to create a printed 'Watch Error Correction' for each watch, so that we can easily look up the Watch Error (WE) for each sight without doing any calculations.

And to verify that our table is correct, we should be able to use it to predict the actual data we observed. In other words, we should be able to back test the model against the original data.

When I tried to do this, using either the 1d rate data in the table, or by curve-fitting the data using the graphing feature of my spreadsheet, I discovered that either result worked well enough to navigate by, but that I could improve on either method simply by tweaking the value a bit up or down, and observing the 'difference' column.

For example, here is a back-test table derived using the daily error obtained using the average daily watch error for Watch A, which I then tweaked until the difference column contained values that were always less than + or - 1. 

Click for full size
Of course, when navigating, we won't want to mess with decimal days or any calculations at all. We just want to know how many whole days it's been since the watch was set, and use that to look up a watch correction.

In the table above, Predicted WE = Day * Watch A daily error (-0.365). Actual is the actual observed error, and Difference is the difference between the two. It is not possible to pick a daily error rate that reduces the prediction error to zero, because we are using whole days. But predicted WE that is within 1 second of the correct WE is more than accurate enough for navigation, making our cheap Casio watch at least as accurate (if not more so) than the most expensive mechanical chronometer.

So, here is a Watch Error Correction table for Watch A that goes out 60 days -- hopefully much longer than I will ever need it to be!

Next Up:

23 February 2020

Let The Preparations Begin

While John is preoccupied with seriously important matters such as planning, organizing, and preparing for our upcoming Atlantic crossing, I am also making sure that we have some extra help just in case.

Coming from Brazilian and Russian background where magic and the power of positive energy is an every day presence, I put myself in charge of making sure that these elements are present in Petronella. I want to make sure that between John's skills, Joshua's strength, and our good luck we will have a very amazing experience.

Bernard Moitessier grew up in Vietnam, where fishing boats have painted eyes on their bows. There are many explanation for these painted eyes. Some say that the eyes are intended to help the boats at sea find their way back to land. Others say the eyes are meant to scare off sharks or water monsters, or are meant to bring good luck and fortune. Some fishermen believe their boats are like fish – beings with souls that must also have eyes to steer clear of danger. A special offering ceremony takes place once the eyes are painted, the offerings include flowers, shrimp, pork and duck eggs.

Joshua has eyes painted on its bow… they are facing forward and down, looking into the ocean. 

We decided to add eyes to Petronella too. And so my mission is to find magic eyes that will take care of us and her before we leave. 

Already thinking of our special offering ceremony, it will definitely have a French flair…cheeses, hams, and wine. Maybe some Jameson.

Next Up: A Chronometer for Celestial Navigation

19 January 2020

High Seas Forecasts, Wirelessly

Last time I was celebrating our getting insurance for the crossing, but you need a heck of a lot more than insurance to get across an ocean. Probably the most important -- and this is why I'm putting it first in my notebook -- is getting high-seas weather forecasts wirelessly.

As a reference for myself, and for anyone else who might be interested, I'm going to collect all the vital information I need to get such forecasts on this web page. I will update it as I uncover more useful nuggets of information.


The world's oceans are divided up into Metareas, with different countries having primary responsibility for providing forecasts for each area. We are interested in Metareas IV (western Atlantic) and II (Eastern Atlantic)


Weather charts are created by weather service professionals who analyze raw data (like that contained in GRIB files) and use their vast experience to produce charts which represent their best forecast of the weather. They also explain their forecasts in the high seas text forecasts, described below.

National Weather Service (NWS): The NWS has the most comprehensive set of weather charts for the whole North Atlantic.
To obtain NWS charts by email, send an email like this:

  To: query@saildocs.com
  Subj: any
    send filename (example PYAA12.TIF)
      - or -
    sub filename time=06:00 days=5

An easy way to compose these emails is to use the Starpath or MailASail Index which allows you to click on an email link for a particular chart, which creates the email for you. It is possible to request several charts with one email. Both indexes provide reduced-size charts that are roughly half the size of the full-size versions (18kb compared to 35kb for the western Atlantic chart, for example.)
UK MET Office: The UK has charts for the eastern Atlantic.
The UK charts listed on the NWS International Charts index can be downloaded using Saildocs. For example:

    send PPVA89.TIF

Bermuda Weather Service: Local charts focused on Bermuda
Bermuda charts can be downloaded using the Saildocs feature that allows full webpage downloads. For example, the current Bermuda chart:

    send http://www.weather.bm/images/surfaceAnalysis/Latest/Local.png

Two, three, and four day forecasts:

    send http://www.weather.bm/images/marineChart/Latest/Small/_chartSmall36.gif
    send http://www.weather.bm/images/marineChart/Latest/Small/_chartSmall60.gif
    send http://www.weather.bm/images/marineChart/Latest/Small/_chartSmall84.gif


High Seas text forecasts work hand in hand with weather charts. They are the explanation of the weather features displayed on the charts, and provide additional information not provided on the charts. You need both charts and text forecasts to get the complete picture.

  • MetArea IV - broadcast by USCG on SSB
  • MetArea II - I haven't been able to locate information on this yet.

To obtain text forecasts by email, send an email like this:

  To: query@saildocs.com
   Subj: any
    send Met.2
      - or -
    sub Met.4 time=06:00 days=5

The Meteo-France reports use name for forecast areas, so you need the following chart to understand them.

Forecast locations in Metarea II


Ship reports are part of the raw data used to create weather charts. But weather charts only display a small selection of all the ship reports that are available. Ship reports let you know what weather all the ships around you are experiencing in near real time. 

Starpath provides a very convenient service: give them a location and they will provide all ship reports within 300 miles. A great way to get near realtime data for the water around you.


To obtain spot ship reports by email, send an email like this:

  To: shipreports@starpath.com
  Subj: 38.2N, 70.3W
  Body: blank

Specify the spot location in decimal degrees, as shown above. The email response will include a list of reports that you can plot manually, and also a GPX file that enables you to import the reports into a navigation program like Aqua Map. I will write a separate blog post on this topic, as it is a bit involved.


GRIB data is raw model data that has not been processed by human meteorologists. To be used only in conjunction with expert analysis and forecasts. 


The simplest way to get wind, waves, and pressure in one GRIB file is to use Saildocs. LuckGrib also allows you to download wind and waves, but you must create two different requests, and then combine the two files (or view them separately.)

To obtain GRIB reports by email, send an email like this:

  To: query@saildocs.com
  Subj: any
    send gfs:41N,35N,79W,56W|0.5,0.5|0,6,...,36,48,...,96|Wind,PRESS,WAVES
      -- or --
    sub gfs:36N,42N,70W,76W|0.5,0.5|0,6,...,36,48,...,96|Wind,PRESS,WAVES time=06:00 days=5

Note: don't allow your computer's spell checker to convert the three periods '...' into an ellipse '…', which is a single character that looks like three periods.  They look the same, but are not the same and the ellipse will cause the request to fail. 

Next time, I will note how to combine and subscribe to most of these requests so the data is ready for download when we need it.


NAVTEX (NAVigational TEleX), is an international system for receiving navigational warnings, weather warnings and forecasts, and urgent safety information, pithing 200 nm from shore. It is not commonly used in the States, which depends on USCG VHF broadcasts and NOAA Weather Radio  for similar purposes, but is very common in Europe. 

(Actually, I'm not sure if you can count NAVTEX as high seas forecasts... More like offshore forecasts. I may move this section to a new page on offshore weather...)

NASA Marine receiver only. Uses iPad for display.
Looks easier to use than the LCD models.

Next Up: Let the Preparations Begin

17 January 2020

We're Go for an Atlantic Crossing!

Okay! It's been a long time since my last post. I haven't really wanted to talk about our plans until I could say for sure if they were going to happen. The good news is, they're happening!

Helena and I have been hoping and preparing to take Petronella on her 12th Atlantic crossing since we first laid eyes on her.

The main obstacle: insurance! Such a boring problem, but one that new long range cruisers must tackle. It's just not practical to sail uninsured. We have been gradually racking up sea miles, trying to convince our insurance company that we are competent enough. This year, we finally got approved.


We just got the news a couple of days ago, so we have shifted our preparations into high gear. There is so much to do, but we are really excited. I will be using this blog as a kind of planning notebook. No idea if it will be interesting to anyone else, but it will serve as a resource for us, and hopefully for others.

What have we been doing in the meantime?

Well, we had the absolute best summer ever, cruising in Maine. If you follow us on Facebook or Instagram, you know all about it, but it was really great. Yes, it's not the easiest place to get to, and you do have to contend with rocks, and pots, and fog, but that just seems to make it all the better when you drop your anchor in a beautiful, secluded cove.


We also met Eléanore, a young French woman, sailing on another OCC boat, who we hit it off with, and who has agreed to crew with us to Europe. Getting the right crew is not easy, and we feel very lucky to have found her.

At the moment, we are actually in France, back in Montpellier for the winter. Petronella is with Howdy Bailey back in Norfolk, getting a bit more steel work done in preparation for the crossing.

We leave sometime in May.

Here are some pics from Maine...

Boothbay Harbor - possibly our favorite
Offshore on the hottest day of the summer. What heatwave?
In Castine, touring a merchant marine training vessel. Very interesting!

The fog comes
on little cat feet.
It sits looking
over harbor and city
on silent haunches
and then moves on.
-- Carl Sandburg

In Belfast - another favorite

Hiking in Belfast

In Brooklin, anchored across from Wooden Boat
The anchorage in Brooklin, Wooden Boat School in the background. 
Stonington. Another great stop!

Anchored in Knox, with about 25 other OCC boats.
A small section of the OCC fleet in Knox

And last weekend, in Saint Geniès des Mourgues at a truffle festival!

Next Up: High Seas Forecasts

05 July 2019

What To Do About Fog?

It was a two-day passage from Huntington, NY to Essex, CT where the Seven Seas Cruising Association was holding a Blue Water Weekend. We hoped to learn a lot from SSCA folk who have already been across the Atlantic and even further. And my small contribution was to talk about getting weather forecasts at sea -- something I've been studying assiduously for the last couple of years.

Anyway,  on the way to Essex we got caught out in fog so thick that we probably shouldn't have been out there at all. But there was no place to anchor, so we had to carry on, slowly, with our running lights on, blowing our lung-powered Trump air horn. This is a blow-hard type of safety signal, but blowing hard every two minutes for hours at a time gets pretty old.

But getting run down by a sport fisherman doing 20 knots was only one worry. The other concern was running over a crab pot. We'd picked one up in the Chesapeake last summer, which was bad enough. I did not relish the idea of jumping into the cold Long Island Sound to cut another once loose. So we had a very long day watching out for boats and hard-to-spot crab pots.

Foggy mooring in Essex, CT
Furthermore, once we got to the SSCA Gam, we had plenty of people tell us that what we'd experienced was nothing compared to what we'd find in Maine, where the fog was thick, the lobster pots thicker, and the water colder.

We have been told by people who should know that if you sail between the Bahamas and Maine a couple of times you will experience all the weather you are likely to encounter when crossing the Atlantic in May or June. Fog was something new for us (we had only encountered it on one day in the last two years, down south), and perhaps new for Petronella, since she was rather under-equipped for it. We decided to add radar, a much louder air horn, and a wet suit to our sailing kit before heading any further north.

After doing a bit of research, we discovered the Furuno 1st Watch Wireless Radar. This is one of the least expensive radar units you can buy, probably because it uses your iPad as it's display device. Just mount it on your mast, supply 12 volts, connect your iPad using wifi, and you are up and running. This sounded ingeniously simple, until I started thinking about mounting it on our rectangular wooden mast. Clearly we would need a custom stainless steel bracket to fit our mast, but could we have one made on short notice?

Nope. "Maybe by August," was what we heard from every welder we could get to answer the phone.

"Nevermind," I told Helena, confidently. "I can make one. Out of oak."

Thus committed, I got to work.

I was able to find some pretty nice kiln-dried white oak at a local hardwood dealer, who was able to run it through his jointer and planer, to minimize the amount of finishing I would have to do with my relatively small set of woodworking tools.

I used my portable bandsaw (otherwise known as a jig saw) to do most of the cutting. I had the clever idea of using oak dowels to stabilize the bottom braces, to keep them parallel and the correct distance apart (the thickness of my mast - 5 inches.)

With a morning's work, I had this:

Bracket for shelf to hold radar dome

With the shelf installed
To make installation on the mast as easy as possible, I pre-drilled all the holes on the bracket. Here it is, bolted to the bottom of the radar dome.

Of course, painting took several days. I used Brightside, but I really don't like to use it on wood. It goes on too gloopy, and is very slow to harden. But I had it, so...

The bracket painted and bolted to the dome.
One worry was how to get this heavy, clumsy system up the mast so I could bolt it into place. I eventually thought of a simple rope sling. This worked very well.

Simple sling tied to radar for hoisting
The radar and bracket hoisted into space, I mean place,
where no radar had gone before.
Then it was easy to drill holes, and screw it into place, using plenty of bedding compound. Thanks to the care I took with the oak pegs, the bracket fit the mast perfectly.

Installing radar on a fogless day. One of many, I presume!

And here is Petronella with the radar dome proudly fixed to her mast. It just clears the staysail leech, in case you were wondering.

P with radar installed
How did it work? Pretty well! I spent an hour or so watching boats move up and down the Connecticut River, and eventually understood what I was looking at.

Here is a screen shot from the iPad radar app. Note how I have marked the position of the buoy and boat, which are about a half-mile down the river.

Screen shot of iPad radar screen.
Note position of buoy and boat on the screen. The boat was moving, the buoy was not.

And here is a photo of the same buoy and boat a few moments later:

Photo of buoy and boat a few moments later.

Of course, we are in a mooring field literally surrounded by 50 or more boats, which you can also see on the screen. The radar also picks up the outline of the shore on either side of the river, which takes a bend at Essex.

In short, it works! I'm anxious to try it out on the Sound on a few clear days so that we can see how it works without so many obstructions and targets around. I'm sure the picture will be a lot simpler to interpret at sea.

We also installed an electric horn on the top of the hard dodger, and purchased a wetsuit, just in case.

I hope we don't need to use any of them!

Next Up: We got insurance to go transatlantic!

21 June 2019

SSCA Weather Talk

Topic: Preparing your boat for blue water sailing

  • My definition of blue water sailing: sailing beyond the bounds of the departure weather forecast
  • Bluewater sailing requires you to be able to get updated weather forecasts while at sea, away from easy internet access
  • Which data? Will vary. For the East Coast of the US, for example:
    • Charts
      • Current surface Analysis
      • 24, 48, & 72 hr Forecasts
    • NWS Offshore Waters Text Forecast, including 'Discussion'
      • West-central North Atlantic FZNT22
      • New England FZNT21
    • Chris Parker’s  FL/Bahamas and US E Coast & W Atlantic Emails
    • GRIB Data for at least:
      • Wind strength and direction
      • Pressure
      • Wave height
      • Wave direction
      • 500 mb
      • Gulf Stream location and speed
    • Voice broadcasts
      • NWS
      • Chris Parker
      • Redundant if you have above.
    • Local barometric pressure (onboard barometer)
  • How to get it?
    • Key Tips:
      • Subscribe to as much data as possible
        • SailDocs - charts, text forecasts, most GRIB data
        • Chris Parker emails
        • Use LuckGrib app - updates by email for models not covered by Saildocs
      • User StarPath Marine Barometer app on phone and calibrate before departure
    • SSB
      • Capture radio faxes directly with computer or tablet app
      • Get Text and GRIB data by email (WinLink, SailMail)
    • Satellite (sat phone, Iridium Go, etc.)
      • All by email
      • Starpath Marine Barometer app
  • How to interpret it?
    • David Burch Modern Marine Weather"
    • Chris Parker « Coastal & Offshore Weather « 
  • Comparing SSB vs Sat Phone
    • Three costs:
      • In dollars (equipment and on-going costs)
      • In electricity
      • In human energy
    • SSB 
      • Dollars: higher in equipment cost, essentially free thereafter
      • Significant drain on the battery when fetching email (on our boat - not a problem if you have lots of electricity)
      • Significant drain on human energy  it takes real work to get the data!
    • Sat Phone 
      • Dollars: lower equipment cost, pricy ongoing costs 
      • Negligible battery drain
      • Negligiblehuman energy drain
  • My experience
    • SSB 
      • Radio fax charts fairly easy to get, but lower quality than email
      • GRIB data and text forecasts by email
      • Battery drain was serious on our boat, may not be an issue if you have lots of power available
      • Frustrating and tiring to use - perhaps because I tried to use SailMail on a Mac. Might be better on Windows laptop
    • Iridium Go
      • Easy to use
      • Reliable once I found the right location for the antenna
      • We have mainly data plan, so have plenty of data for the year
    • Bottom line: Iridium started out as ‘backup’ to SSB, but the roles soon swapped. The last trip, we used Iridium exclusively.
Try It Yourself

Send the following in a plain text email to query@saildocs.com:

sub http://tgftp.nws.noaa.gov/fax/QDTM85.TIF time=06:00 days=2
sub http://tgftp.nws.noaa.gov/fax/PYAA02.TIF time=06:00 days=2
sub http://tgftp.nws.noaa.gov/fax/PPAE00.TIF time=06:00 days=2
sub http://tgftp.nws.noaa.gov/fax/PWAM99.TIF time=06:00 days=2
sub FZNT21.KWBC time=06:00 days=2
sub FZNT22.KWBC time=06:00 days=2
sub gfs:25N,44N,70W,80W|0.5,0.5|0,6,...,36,48,...,96|Wind,PRESS,WAVES time=06:00 days=2

Doing so will subscribe you to weather charts, text forecasts, and GRIB data for 2 days. For an actual offshore passage, you could extend the subscription for duration of the passage.

For Gulf Stream data, send the following in a plain text email to request@offshore.luckgrib.com

grib: 1200fwnizI5ryxy8395LO9pinXXSRuSjmISjv4pYqnPSPpbn4RSPMgg4Ivp

Next Up:  What to do about fog?

14 June 2019

First Big Steel Job

Meeting the remarkable Australian cruising couple, Neil and Ley Langford, last year really opened our eyes to the possibility of DIY steelwork. They showed us all around their beautiful steel boat Crystal Blues, and then showed us pictures of the many, many steel jobs that they had done over the years.

"That's the beauty of steel boats," they said. "If you wonder if something is rusting, just cut her open and look. You can always weld her shut again."

They had done just that several times, to fix tanks and other things. No need for that kind of work on Petronella, but there was one steel job that I had on the schedule for our St. Mary's haul out. Thanks to the Langford's example and encouragement, I was sure we could tackle it.

Cutting out the Engine Vent Assembly
The problem was in Petronella's engine vents. Behind each of the four holes above was a steel elbow, to which were attached flexible air ducts. Three of these elbows were rusted clean through. If we were to take a wave over the stern and fill the cockpit footwell, water would gush through these holes onto the top of the engine and into the bilge. This was unlikely to happen, but since we were preparing Petronella for her 12th Atlantic crossing, fixing this problem was near the top of my to-do list.

My plan was to cut out the whole vent assembly, and then have a welder fabricate a new one. The first problem was to cut it out in such a confined space.

My jigsaw, equipped with a metal cutting blade, made short work of two sides, but it was too large to get to the other two sides. I tried several tools, including a bare hacksaw blade, but the guys in the yard recommended an oscillating multi-tool. I'd seen these in hardware stores, but had no idea how they worked. Turns out, they work pretty well at cutting steel in confined spots. It is easy to burn out the rather expensive blades, but once I backed off and let the blade do the cutting (always a good idea with a cutting tool), it worked great.

My new favorite tool
In the pic below, you can see the problem clearly: three of the vents were rusted through. One so badly that it literally broke off when I tried to disconnect the vent hose!

It was definitely time to replace them!

The old vent assembly
Here is the hole left behind, with all the rust and dirt created by the cutting cleaned up. A bit ragged, but I was glad that part of the job was done.

The resulting hole in the footwell

So, I gave the old vent assembly to Rocky at St. Mary's so he could fabricate a new one. Meanwhile, I wanted to clean up some of the rusty bits you can see in the photo above, prior to painting the area.

I set about this job relieved that I had had the nerve to tackle this project and that a major problem would soon be fixed.

Air-powered needle gun
Neil had recommended we buy an air-powered needle gun last summer. I'd immediately bought one, but this was the first time I'd used it. A needle gun is the ultimate tool for chipping rust and old paint off steel. The yard had a compressor, so I grabbed the opportunity to give it a try.

It worked great, and I discovered that the needle gun was also good for opening cans. As in 'can of worms'.

What the needle gun revealed..
After a minute or two blasting away at the small line of rust in the footwell, I soon discovered a big surprise: the joint between the floor and back wall of the footwell was rusted through in several places. Someone had caulked these holes with some sort of silicon goop, but the goop was loose and the holes were no longer effectively patched.

What happens when you don't look (or paint) under the footwell floorboards for a few years.

I found this depressing, and at the same time thrilling. Since buying Petronella, Helena and I have been on a quest to cure all leaks. Water, diesel, anti-freeze, or whatever. In this quest, we had replaced a leaky water pump, replaced several old hoses in the cooling system, and replaced the engine injector fuel lines. This eliminated most of the leaks and nasty diesel smells, but there was still a persistent slow leak that did not seem to correlate with motoring or rain storms or any other potential source of the leak.

I was convinced we had a leaky water tank, but I had put different colored dye into each tank and waited for colored water to appear in the bilge. Nope. Not trace of dye. Just clear water.

I'd nearly given up in despair, but seeing these holes rusted through in the footwell seemed like an Ah-Ha! moment if there ever was one. I never would have suspected the footwell was leaking, but because I'd had the nerve to fix the engine vent, and furthermore took an obsessive approach to prepping the hole for painting, I'd uncovered what could be the source of our sneaky leak.

Repairing the holes with epoxy and fiberglass.
I set about the footwell with the needle gun with a vengeance, and soon discovered several other rusted-through holes that had been also patched with silicon. I soon had all these old patches out, and the rusty areas thoroughly prepped with the needle gun and rust converter. After consulting with both Rocky and Howdy Baily, we all agreed the best way to fix the holes was with epoxy and fiberglass.

The floor of the footwell had been removable to provide access to the engine, but this had probably helped cause the problem in the first place. We agreed that when Petronella needed re-powering in the (hopefully) distant future, that would be the time to cut out the whole footwell and replace it with a new one.

For now, fiberglass would make the footwell truly waterproof and strong enough for whatever we threw at it (or into it.)

The new vent assembly
The new vent assembly arrived, and we set about prepping it for painting and installation.

We had had the assembly built 3/4" larger, all around, so that it could be bolted over the hole, rather than welded in. This was because Rocky was worried about welding over the engine compartment, with its risk of fire.

Eventually, it was time to bolt it in.  We reattached the vent hoses with new hose clamps (the old ones were rusted badly) and bedded it down with 4200.

Bolting the new assembly into place
And here it is, job done. The footwell could use one or two more coats of paint to 'finish' the job, but we ran out of time in St. Mary's. We will get to that whenever it stops raining and warms up here in the North.

Job done
We took these pictures back in St. Mary, but I haven't wanted to declare victory over our leak until today. The leak was just too elusive and random for me to trust that the footwell had been the ultimate source, at least until we had been leak-free for a whole month. It had been so maddening that we hadn't been able to correlate the leak to rain, or running the engine or any other potential source of water. I now believe that the leak had correlated to the taking of cockpit showers! Not that we tracked these, so we never made the connection.

Since we nearly always have our awning up when it rains, we never got much water in the cockpit from rain storms. But when we decided to shower in the cockpit, we would often dump several gallons of fresh water into the cockpit. That's where the water had been coming from.

So, a mystery that had stumped us for 2 years was finally solved. Our bilges are now dry and Petronella is as watertight as she was when launched in 1976. It's a good feeling.

Thank you, Neil and Ley, for showing us the way. I hope you are doing well wherever your travels have taken you.

Next Up:  SSCA Weather Talk

06 June 2019


So we still haven't got to Block Island. Helena was running out of time before her next trip to Brazil (aging parents!), so we opted to spend the week visiting with old friends at the Ketewomoke Yacht Club in Huntington, NY.

The Memorial Day party was even more fun than usual, and when it was over (as usual, Helena and I were among the last to leave), the water off the club dock was glassy smooth. Perfect for trying out a new low-light camera app on my iPhone. The app is called ProCamera, and boy does it take great low-light photos. A vast improvement over the free Apple Camera app, I think.

KYC at midnight

Petronella in a ghostly calm

The Huntington waterfront
Once I got Helena off to Brazil, it was time to stop partying (well, for the most part) and get back to my to-do list.

One thing I've really been meaning to do is to build a lifting sling for our PortaBote dingy. I have been experimenting with various ad-hoc variations and have finally settled on a system that works reasonably well. The balance point of the empty dingy is just aft of the middle seat. Using a three-legged sling - one leg to the bow seat, and two to the stern seat - seemed to work best. It was time to build a proper sling -- one that would easily snap on and off the boat without a lot of knot tying. 

Here is the sling in progress, with its center ring and three legs. The three legs are long enough to wrap around their respective seats and clip on to themselves. For lifting, I will clip the mainsail topping lift to the center ring and haul away. 

Building a lifting sling for the dingy
And here it is, test-fitted to the dingy. All that remained was to finish the last splice on the forward line. That is now done, and the sling is ready to go. I will take pics the next time I hoist the dingy aboard.

Test fitting the sling

Another dingy project that needed doing was figuring out a better way to tow the PortaBote. This popular folding dingy is ideal for cruising, in many ways, but lacks one essential feature: a towing eye. I think this is because they don't recommend towing the dingy, but sometimes you just need to drag it from one anchorage to the next. That's just real life. And even in the ideal, non-towing world, you still need to tie it up to a dock. The lack of any place to tie even a dock line is a real problem.

Luckily, the PortaBote comes equipped with a sort of bow covering that is practically useless. It attaches to the boat using two grommets in the bow. Practically everyone uses these grommets to attach a painter, and I'm no exception. 

I have tried several different ways to attach a painter to these grommets, none successful. Last summer, I saw another PortaBote with a kind of bridle, like the one below. I've been meaning to install one since that day, and I have finally done so. I will be towing the boat for a few hours later this week. I will be very interested to see if this bridle chafes severely, as all previous ones have. We shall see.

Towing bridle
Tomorrow I am off somewhere. KYC has been great to let us stay on their washdown dock for two weekends. I don't want to abuse the privilege, so I want to be off the dock by Friday so the members can enjoy their dock again. 

Thanks to everyone at the amazing Ketewomoke Yacht Club for your friendship and hospitality. I do miss you guys.

Next Up: First Big Steel Job