Top Menu

Imagine that you have a large telephone pole right beside your house and that, instead of it being partially buried in the ground, it is supported only by three equally-spaced guy wires. Now imagine that you want to do some work on one of those wires so you need to remove it. It doesn’t take a geometry wizard to figure out that the pole would now be a lot less stable and could easily fall down in the direction away from the wire you removed. Hopefully it doesn’t smash your house if it does!

The above it pretty much what we needed to do yesterday with our mast. Our mast is deck stepped meaning it is just sitting on top of the deck and, unlike many boats, it is supported by only three wires (2 shrouds and a head stay). We needed to install the Hayn insulator in our starboard shroud so we commissioned Greg, from Atlantic Rigging to get it done. Greg did an excellent job and I have to say this may very well be the first time anyone has ever completed a job in less time than I was quoted! It took him less than 2 hours from start to finish, and most importantly, the telephone pole (our mast) didn’t come down crashing into our house (our boat). Whew. We are glad that is done!

If that job wasn’t exciting enough, we also decided to equalize our batteries for the first time. I found this link which describes this process:

In a typical equalization cycle, the battery voltage is allowed to rise to approximately 16 volts, where it is maintained for up to eight hours by adjustment of the charging current. This process helps to mix up the electrolyte, which otherwise tends to “stratify” (i.e., separate into overlappying layers of acid and water), and is also useful in removing some sulfate deposits. When performed properly, equalization doesn’t make the battery boil over, but does produce fairly vigorous bubbling.

We were cautioned to turn off all of our DC circuits while doing this as many things don’t like the high voltages that are created during this cycle. Additionally, one needs to be careful to keep the battery area well vented and to not create any sparks around them as the gasses emitted from the batteries during equalization are explosive! That sounds scary, doesn’t it?

Because I am typing this now you can correctly assume that our batteries did not blow up and all is well. We are pretty much ready to depart the Chesapeake area and start heading south again. Of course, we’re expecting winds to be gusting to near gale force on Friday, which may just delay our departure. We’ll see.


  1. Still making Zero to Cruising reading a must with my morning coffee. Love all the tips.

    So did I read that your friend John with the power boat is going on a sailing trip? I’m thinking your wonderful blog is converting him ? ? ?

  2. Mike, with hydrogen (what your off-gassing batteries are producing), it is hard to be too cautious. Hydrogen has one of the widest explosive ranges (from 3-4% to 75% in air) known – compare that with propane at 2.5% – 9.5%. Oh, and that is in *air*… But your battery off gases are a beautiful perfect mixture of hydrogen and oxygen.

    Ventilation (non-sparking!) is your friend.

    • I’m glad you posted that now and not while we were doing it! I would have been even more scared.

      Fortunately for us, all of our batteries are in the cockpit and we can open up the hatches which enclose them. I’m sure the wind yesterday helped to blow it away too (we kept our companionway door closed).

    • It is also very helpful that hydrogen rises. Fast. If the battery covers were off I doubt it was on the boat for long. Propane is much worse that way. Fortunatly, the battery cases on the PDQ are in the cockpit and not below.

      I used engineer at an industrial wastewater plant that generated hydrogen when disolving metals. We engineered for fires in the reaction tanks, and they happened! The scary part was that you could hear the explosion (the tanks were built with hinged lids to releave the pressure) but you could not see the flames. No damage was ever done, because of such design features.

  3. John & Phyllis on Morgan’s Cloud have been running a really great series of articles on battery care over the last month or so….
    The series takes a while to read, but is well worth a look if you’re trying to milk every last drop of value and lifespan out of a cruiser’s house bank. They use AGMs, so a few of the details will be a bit different if you’re using wet cells.

  4. What’s great about the Hayn insulator set-up is that is now the strongest part of your rig.

    Fair Winds,

  5. OK, Maritime Mobile, you are now cleared to transmit! See you down the log, I hope. 73s

    • We checked in to the waterway net this morning while on route. Our reception was much better I think, partly due to being out on the open water but I also think the improved antenna helped a lot too.

  6. Happy to hear Atlantic Rigging treated you right!

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

This site uses Akismet to reduce spam. Learn how your comment data is processed.