On Board with Mark Corke

Battery Test

Many boat owners have volt meters on their boats which are very good at telling you the condition of your batteries. You can tell a lot with a volt meter and although I have a meter built into the boat's electrical panel one of the portable meters like this $20 model from Radio Shack is an indispensable aid to have in the tool kit as you can do so much more than just check voltage. But back to the battery test as I am doing here. With the meter switched to DC volts and the probes touched to the terminals you will get a reading. You might think that if a 12 volt battery reads more than 12 volts it is fully charged and in good condition - wrong. A fully charged battery of the wet cell type like the one shown when fully charged show will a reading on a voltmeter of 12.65 to 12.7 volts, between 12.4 and 12.6 volts it is approximately 75% charged, at 12.3 volts 50% charged and the battery in the picture at 12.1 volts is flat and incapable of starting the engine.

If you have gel or AGM batteries on the boat these figures are higher with 13 volts representing a fully charged battery.

I ought to mention that when testing the open circuit voltage with a meter it is important to let the battery rest before taking a reading. A battery that has just been charged via the alternator will have a surface charge on the plates giving an artificially high reading. You will get the most accurate results if the battery is disconnected and you wait half an hour before connecting up the volt meter.

While we are on the subject of batteries I did mention the other day in my post on the Blue Sea systems VSM 422 that the battery temperature sensor was an extra cost option. My good friend David Johnson at Blue Sea has pointed out that in fact the unit does in fact come with a sensor included in the box so making the unit appear even better value for money.

Boat Surveying

 This cool picture is actually not that cool. It is an infra red image of a power boat and shows large hot spot but that is not the reason that I have included it in this post. It is an unashamed plug for my survey business. Some readers may know that when I am not writing this blog or working on boats I undertake boat surveys. I am a Surveyor Associate member of SAMS (Society of Accredited Marine Surveyors) and have experience of surveying craft of all types. I would be happy to talk to anyone about a survey whether it be for insurance or a pre purchase survey. Because of my geographic location most of my surveys are up in the New England region but I can and frequently do travel to other parts of the country. If you would like to talk to me bout a survey then please e mail me and we can go from there.

Electrical panels

    This handsome and well organized electrical panel is fitted to a Cherubini 44 everything is neatly labeled and laid out in a logical fashion. Sadly many boats are not quite as good as this. The wiring on many older boats may be fine and up to ABYC standards but over the years extra supplementary switches get added as new equipment is installed and before you know it everything becomes a mess, nothing matches and there is no logic to the electrical layout aboard.
    I see this type of thing a lot when surveying boats. Back in the day on even large boats there was little use for large electrical panels, GPS, radar and other electronic aids to navigation did not exist or were outside of the realm of the yachtsman. If I remember correctly on the 72 foot yacht that I used to skipper there were no more than 10 switches. We had no AC power aboard, the cabin was mostly lit with oil lamps, the bilge pumps were all manually operated as were the toilets so our electrical requirements were pretty small.
Now I bet if I went aboard the boat today it would have all the modern conveniences and then some all requiring a large electrical panel.

    It is with this in mind that I have been thinking about upgrading 'Mallard's' electrical panel. The quandary is that while off the shelf units like those from Blue sea systems are excellent units they don't always address the exact requirements of the boat owner and so it is with me so much so that I have been thinking of designing a custom panel.

    One such outfit that makes these one off panels is Mobile Marine from Newburyport in MA. They were showing at the Maine Boat builders show this year as they have in the past and I really like what they can do. Their panels look neat and well thought out and they are able to make almost any configuration it would seem. One other firm which is worth checking out is Front Panel Express which has free down loadable software that lets you design your own panel. Sadly this is only available for Windows at present and as I use a Mac I shall have to wait until I can get hold of a PC to give it a try. I have seen panels that other boat owners have designed for themselves with this system and the results are impressive.

Designing the panel is all very well but I know what is going to happen, just as I get it finished and installed I'll need to upgrade again to incorporate the latest gizmo!

Stand up springs

    On a sailboat blocks that are attached to pad eyes or tracks can flop around and damage the finish of the boat, decks get scratched and gelcoat cracked. I was getting especially mad when my genoa sheet blocks would bash into my  bright-work and mash up the varnish in no time flat.
    When the sheet is under load the block is held clear of the boat but the lazy sheet still flaps around and damages the boat. Stand up springs prevent this from happening as they make the block stand up straight even when no rope is rove through them as shown here but getting the springs into place can be a real pain.  The problem is that you have to compress the spring as you reassemble the block, pushing the clevis pin back through the fitting then threading on the split ring. It is all too easy to lose some vital part as the spring is want to throw bits and pieces in every direction, usually to the bottom of the sea.

    A neat trick is to use some small zip ties to hold the spring in compression as you assemble the fitting then when everything is installed simply cut the ties with a knife and voila a perfect job with no missing parts and no rude words.

Boom tent - Mk 1

One of my projects of late has been a boom tent that I have been making for Mallard. The reason for the tent is threefold. primarily it will give us more living space aboard when we are at anchor or in a marina slip, secondly it will keep water out of the boat and keep the sun off the boom and mainsail and thirdly it will cover much of the bright work which when not exposed to the damaging UV rays should last longer and be easier to keep in tip top condition. I ought to mention that the boom tent will not be made out of Tyvek but I have found that it makes a fantastic material for making patterns.

I spent a long time thinking about the best way to make a boom tent. The obvious way is to simple use the boom as a ridge pole and have material strapped down to the toe rail. While this approach would keep the sun and weather off the boat I discounted this idea early on as it would give very little room in the cockpit. What was needed was something else I surmised so after much head scratching I have come up with the design that you see the beginnings of here. Flexible fiberglass tent poles spaced at 24 inch centers sit into sockets on the inside of the toe rail. Because the width of the boat varies I cut the length of the poles so that when slotted into the sockets the apex is level fore and aft. The poles seem to work well, they give a nice rounded shape to the tent which leaves plenty of room inside for sitting on the cockpit seats and the poles self support the tent so that it will need minimal rigging to hold it down to the boat.

Here's a picture of me taken by my good fried Tom Dunn as I mark up the inside of the Tyvek. I am marking the position of the poles so that when I sew up the Sunbrella material I can to put pockets in it through which the poles will slide. There will be ends on it too both forward of the mast and at the stern which as you can see in the picture is open at present. I now have the pattern at home and am starting on the sewing. As soon as I have got along a bit further I'll bring you an update on progress here.

Safety netting

Look around almost any anchorage and you can spot the serious long distance voyager; extra fuel cans tied to the deck, wind generator and solar panels and most likely if my boat is anything to go by a couple of gently rusting bicycles strapped to the pushpit. Look closer and you might also spot some netting strung between the lifelines and toe rails. When correctly done netting makes a wonderful addition to almost any boat. Originally I started to use it aboard 20 years ago to prevent my son Sam from going over the side by sliding under the lifelines but I quickly realized as time progressed that there were other benefits too. Large headsails no longer fell into the sea as I wrestled them to the deck in less than perfect conditions and there was a psychological advantage when we took novice sailors out who felt a little more like they were in the boat rather than sitting on top of it. Installing netting is a straightforward job but it does really require two sets of hands, you can do it on your own but it takes much longer and is easy to tangle everything up, get frustrated and generally make a mess of it.  Netting comes either in a roll or can be bought by the foot, measure carefully because it is easy to buy too much as netting stretches a good amount. Know the length between the pushpit and the pulpit by measuring along the top guard rail wire and have this in your back pocket when you go to buy.

It may seem like stating the obvious but it is pointless spending time rigging netting unless your guard rails and stanchions  are in tip top condition. Check them and tighten any wires that are loose and consider replacing any swaged fittings that are bent, cracked or at all suspect.

On the face of it plastic cable ties would appear to be the perfect product for attaching the netting to the boat but bear in mind that they are degraded by UV which tends to make them brittle and fail. Periodically check them by giving one or two a good tug, if they break easily replace them. I prefer whipping to cable ties as they are kinder to bare feet and hands and can be cut easily in an emergency with a knife but it is all down to personal preference.
One final word and that is that the netting like anything else on the boat will require some maintenance, not a lot but at least give it a good visual check once or twice per season and remember that it could be you that it prevents from going over the side.