On Board with Mark Corke

Bleeding a diesel engine

    In spite of all my years of boating I am still surprised about the air of mystique surrounding diesel engines. On of the comments I hear a lot is that diesels are complicated to work on and not as simple as a gas engine. In fact, nothing could be further from the truth.  A diesel is in fact less complicated than a gas engine, uses a less dangerous fuel, gets more mileage and does not rely on a spark to ignite the gas.

Water filters

I have spent at least part of the day today changing various filters on the boat. One of the filters that I often forget about is the water filter or should I say filters as there are several on the boat doing similar jobs but for different end results. I have to say that I feel quite smug with myself as this year I have managed to remember them all whereas in the past I have left the filters till too late and the water has tasted bad for some time afterward. This little  sink under mount unit is the very popular and efficient Seagull  which retails for around the $300 mark and for the way that the water tastes is in my opinion worth every penny, in fact these filters work so well that I believe the water on my boat tastes better than my water at home.

They come with easy to follow instructions but do heed the warnings about filter life, ideally you should change it every year but it will last a couple of years I have found, as on board you typically don't run much water through in a season.

One word of caution however and that it remove all water filters and drain down the hoses if you live up in the northern parts of the country. If the filter is allowed to freeze it will crack the casing as I found out to my cost a couple of years back,

Cable wiring sizes

    I have had few e mails from readers asking for extra information on boat wiring. Whole books have been written on the subject and I am certain that wiring on a boat is something I will be returning to again and again in On Board.

    To help you get started here is table to assist you in choosing the correct size cable for almost any job on board.

    The chart is fairly easy to follow but a few tips may help if you are at all unfamiliar with electrical wiring. The column on the left is the distance in feet that the cable will run and the maximum amperage draw on the circuit is shown across the top starting at 5 amps and finishing at 100.

    As an example say you want to install a 25 watt light located 30 feet from the distribution panel then the first thing to do is figure out the amps that the light will draw.

AMPS = Watts/Volts thus 25 watts /12 volts = 2.08 amps. As the smallest cable listed is for 5 amps we will use this and  in any event you should always round up to the next larger size if the number falls between two of the amperage figures. Following the  5 amp column down we see that the size next to 30 feet is 12 AWG (American Wire gauge) but, when calculating the figures it is the complete circuit length that we are concerned with which is double the 30 feet as the cable has to run to the light fitting and back to the panel making this 60 feet in total which makes this 10 AWG, the next size larger.

    Using the wrong size cable will lead to voltage drop and in this case would cause the light to be dim and in cases where the cable is way undersized could lead to overheating of the circuits.

    Regular readers will know that I am a keen advocate for LED lighting which draw significantly less current than incandescent bulbs. Given the price of copper cable considerable cost and weight savings can be made as the cables needed to supply LED will be significantly lighter in gauge.

    One final point, using the correct colored cable helps in tracing circuits later. The universally accepted colors are listed below. The chart may look a little small on your computer screen but you can make it larger by clicking anywhere on it which will make it easier to read.

Proper electrical connections

   These are something that has no place on a boat - wire nuts.

I recently surveyed a power cruiser which had lots of alterations to the electrical system, not only were many of the connections made with wire nuts the cable was solid core rather than multi strand tinned boat cable, both of which are a big no-no on a boat. Wire nuts are not moisture resistant and cable with a solid core is susceptible to vibration and fatigue eventually leading to failure.

For the complete step by step guide to making proper electrical connections continue reading ..

Time for a laugh

    It's been a very busy weekend for me, I have done a bunch of projects on the boat which I will tell you about tomorrow but I am too tired to write much this evening. In the meantime I wanted to share this cartoon with you that a friend sent me and I hope that you never find yourself in this position in real life.
    I would also like to take this opportunity to say a big thank you for all the encouraging e mails and comments that I have had about On Board. The number of visitors grows daily which is very encouraging. Thank you all, keep the messages coming and I will respond to everyone.

Winch service

    Many sailors believe that it isn’t broke don’t fix it but a regular check up of your winches will keep them running sweetly.

All but the smallest sailboats have winches. Some sailors expect their winches to work year after year with little or no maintenance; others seem to think they are too complicated to mess with and are best left undisturbed. But winches are expensive, have a hard life, and are often subjected to very heavy loads when they are needed the most. It pays to look after them.

Overhauling a winch for the first time can seem daunting, but if approached methodically it should take no more than an hour to service one. After you’ve done it once or twice, you’ll wonder what the fuss was about.
  You won’t need much equipment for this job, but it pays to get what you do need ready beforehand. You’ll need plenty of clean rags, some mineral spirits or kerosene, and an old coffee can to clean dirty parts in. You’ll also need a couple of screwdrivers, one small and one medium size, and perhaps a set of needle-nose pliers for replacing small parts like pawls. All the major winch manufacturers supply overhaul kits, which include grease for the bearings, oil for the pawls, pawl springs, a small brush, and an instruction booklet. These are well worth obtaining.

The Lewmar kit, for example, retails for around $20 and is universal to all their winches. All the major manufacturers also have helpful Web sites; Harken, for instance, has an on-line parts list for their complete line.
  Once you’ve got all you need, follow this step-by-step guide. The photos show a small self-tailing Lewmar winch (the differences from manufacturer to manufacturer are minor). The major parts of all winches, as shown in the accompanying diagrams, are very similar and should closely resemble those in the photographs.

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1. All major manufacturers supply kits for servicing their winches. These usually include tools, pawl springs, and instructions. Winches should be serviced once a year

Woodworking with a blow torch

    Some time ago I was up looking at a new boat at the Sabre factory in Casco, Maine. While there I toured the yard and was impressed by the quality of craftsmanship and the dedication of the workers, many of whom have been with the firm for many years.

Considering that these are fiber glass boats it is surprising just how much woodwork there is to each boat. Sabre has a large wood shop with a CNC router for cutting out many of the components and it is impressive to see this giant machine operating, but even so a large amount of handwork goes into each boat.

One of the signatures of Sabre yachts has always been their high gloss salon tables and I have always wondered just how they get such a fantastic finish - well now I know, with a blow torch, and to prove it here is the picture.

The secret is that they first flow on a coat of clear coat epoxy which self levels, then after letting it sit for a minute or two the varnisher goes over it with a blow torch. Sweeping the torch briskly across the epoxy pops any bubbles present in the surface and the warmth further smoothes out the already glossy finish. For optimum results it is best to use a couple of coats it seems, but you can easily over do it, the finish is fairly thick unlike varnish and too may coats may make the surface appear plasticy.

This was a great tip and I can't wait to give it a go myself. Just as soon as I have I'll share the photos with you here.

Teak treatments

    Now I could be opening up a can of worms here as I know from past experiences that opinion is firmly divided on whether or not you should treat a teak deck. Teak is a wonderful wood for boat building, naturally resistant to rot it contains oils that preserve the the wood and inhibit wood boring critters and when varnished looks stunning, although I hasten to add never varnish a teak deck. Teak is  ideal for decking and can be left to weather to an attractive silver gray with no further maintenance required other than an occasional wash down to keep it in tip top shape.
I like the silver gray look but I do recognize that it is not to everyones taste so what follows is my guide to bringing back some color to sun bleached teak.

1. Wash off all the loose dirt and crud from the deck using fresh water and a gentle boat soap. I favor the Latitude 43 organic boat soap which is kind to hands and deck and will not harm fabrics or paint should they be splashed. As I am doing this as a demonstration I am working on a teak hatch cover in my workshop but the principles are exactly the same for a complete boat deck. Brush across the deck with a soft bristled brush, most deck scrubbing brushes are way too aggressive for a teak deck and many a deck has been ruined by over zealous scrubbing.

   

Tip. When ever you brush a deck always work across the grain. Brushing fore and aft along the deck scuffs out the softer wood fibers and leaves behind a ridged deck which will age prematurely.

Signal flags

    To the uninitiated this might look like a handy spot to keep cans of beer but this beautiful piece of teak joiner work is in fact a flag locker.

I was aboard this handsome  vessel the other day and spotted this as I went below into the main saloon. Not often seen on boats these days these little pigeon holes are for housing international code flags.

Before the advent of 2-way radios, GPS, radar and all the other electronics that we seem incapable of going to sea without, vessels ventured around the globe with no other method of communicating than by signal flag.

I used to skipper a 72-foot ketch and like the boat shown above it too had a locker adjacent to the companionway steps. We used to use the boat for sail training cadets and each of the boys had to be able to send messages by flag.  As soon as I saw the locker aboard this old 1930's boat the memories came flooding back.

Although not used much for sending long messages anymore I think it's prudent to be able to recognize each individual signal flags as they all have single letter meaning i.e.  U = running into danger, Z = I require a tug,Q = my vessel is healthy and so on.

Varnishing Point

    Getting a good finish with varnish takes time and patience but it also helps if you follow this tip. When you have everything ready, the wood is all prepared, you have banished all the dust from the work area and you are just about to lay on the first of several coats warm the can of varnish in a tub or basin of very hot water. Ideally you want water that is almost at boiling point. Stand the can in the sink or a bucket and add hot water until the water is almost up to the rim. If the water starts to cool pour it away and add some more hot water. For a quart can let the varnish stand in the water for 10 to 15 minutes. The heat will thin down the varnish, make it easier to mix and strain but best of all it will flow onto the wood much better with less drag. The warmed varnish will also  'relax' allowing brush strokes to almost disappear before your eyes giving a much better final result.

    Incidentally Goldspar varnish from Interlux is my product of choice but this tip will work with just about any varnish although if you use Epifanes which has a high solids content you should let the varnish stand longer in the warm bath as it will take longer for the warmth to permeate through the finish.