On Board with Mark Corke

Hull Identification numbers

 

Have you ever looked at the number on the starboard side of your transom and wondered just what all those letters and numbers mean? You are not alone. But they do actually mean something. The first three letters are the MIC or manufacturers identification code. The next 5 numbers or letters are what ever the boat builder wants to make them and can typically  denote the model, the series or whatever else they fancy. The next letter, in the case above D denotes when the boat was certified or built. In this case April - A is January runs through to L which is December. The next number is the year the boat was certified or more likely built which in this instance is 9 for 1989 and finally the last two digits represent the model year which is also 1989 but it could just as easily be a 1990 or 1988 model.

So now you know.

Garboard plugs

 

This sequence of shots shows the stages necessary for installing a garboard plug into the bottom of a boat. One would think that drilling  hole in a boat is the last thing that you would want to do but in fact this can save damage to your boat during the winter lay up season. Garboard plugs used to be very common on wooden boats and in fact still are on traditional craft. The idea of a garboard plug is similar in principle to drain plugs that you see fitted into the transom on many sailing dinghies and other small craft. When the boat is out of the water the plug is removed and any water collecting in the bilge is free to run out of the boat. The thinking is that fresh water has killed many a decent wooden boat. Sea water is something of a preservative but fresh water will, if left in the bilges soon rot the bottom out of a wood boat. With a bronze garboard plug installed this can be removed when the boat is out of the water and any accumulations of rainwater will be free to run out. Providing the boat is properly limbered and the garboard plug is installed in the correct area very little water can accumulate and if there is no water then it cannot freeze in severe weather. All of which makes total sense. Anyhow this boat is a small motor sailer and is of fiber glass rather than wood but the rationale still holds good. You do not have to put antifreeze in the bilge in the winter and water cannot collect so the boat will remain dry.

 

So the first step is above and consists of drilling the hole with a suitable hole saw after checking very carefully that you are drilling in the best place and not into a fuel tank or some other vital piece of equipment.

 

Next the anti fouling is scraped back around the hole.

 

The garboard plug is then installed after using some suitable caulking such as 3M 4200. Do not use 5200 or you will never get the fitting out if you ever have to without damaging something.

 
After drill suitable pilot holes the fitting is screwed into place with bronze screws. On no account use brass which are too soft and will dezinctify  in a very short time and waste away.

 
Clean up the surplus goo with a clean rag and some denatured alcohol or acetone.

 

Finally screw in the tapered plug until just snug. Job done, just remember to remove it come the winter lay up time.

 

 

Boat storage

 

A very poor quality picture I know but just look at the blocking beneath the boat, and they expect me to climb in that to do a survey! One gentle puff of wind and the whole boat is going over.

Cable markings

 

This picture was taken with my cell phone so I apologise for the poor quality but it does show each of the conductors marked with an identifying tag. Marking each cable at both ends with the same legend makes fault tracing so much easier. There are a bunch of different ways of marking up the cables and you can use any numbering or other system that works for you as long as you can understand it. For peace of mind I like to have a schematic of the wiring and a list of all the numbers that I have used on the boat's wiring readily to hand so that if something is not working I can find the fault more rapidly, or at least know where to start. Even on a small boat there can be a lot of wiring so it pays to keep it neat and well in check. ABYC guidelines suggest different color codes for different devices and circuits but this gets complicated in my view and expensive. I personally prefer to use red for all DC positive conductors and yellow for DC negative. Providing that each conductor is marked with the tags mentioned above then you will not have any problems and only having to buy several rolls of cable of all the same color makes ordering easier. Incidentally you may wonder why I suggest yellow for the DC negative. This was introduced several years ago so that boats that may have both DC and AC circuits could differentiate between the two.

The wording from the ABYC is as follows;

' For boats sold in the United States either color (Black or Yellow)  can be used. Yellow was added as an option to allow the differentiation between the AC systems line conductor and the DC negative on boats with both AC and DC electrical systems. Even if the boat does not have an AC electrical system, yellow may be used for the DC negative conductor.'

One final point the electrical circuits shown in the pictures are of a small center console boat and if I have to find fault with something it has to be the use of green wire for a positive conductor even if it does have a red crimp sleeve at the terminal.