On Schedule !

Week 3

Week three started better than the previous two. We managed to get to the boat on the Monday.

Our intention was to start on the wiring but, first of all, there was the matter of some missing foam. We had applied some replacement foam during our visit on the previous Saturday. We'd left the cap on the canister when we left, in an effort to stop the ongoing weep of foam after we'd finished using it. The foam around the canister's valve hadn't set when we got to it on the Monday morning. Furthermore, when we tried to clean up the excess, which could normally be broken off, we had no luck. Nor could we encourage any more foam from the canister. Having spent about thirty minutes on this, we discarded the canister, declaring it a failure and adding a new canister to our shopping list.

We then turned our intention to the wiring runs. We'd been very good and worked out what lengths of the various wire sizes we would need. We noted down these lengths and used them to calculate the appropriate cable sizes, based on projected current flows, which we'd also noted down. We'd summarised the individual lengths of cables against each cable size. Have you spotted our deliberate mistake yet? We hadn't actually noted down the results of our computations against the individual circuits. Consequently, we didn't know what size cable we'd planned to use on each circuit. Silly, or what!

Fortunately, we still had the component figures from which we had produced our shopping list and, with a bit of fairly basic detective work, we were able to work out the cable sizes for each circuit. We then had another surprise!

We'd bought the wire we needed during our inaugural trip and loaded it on to the boat as we passed through Braunston. The stock of wire had been moved several times in the intervening period. We now tried to arrange it in some kind of orderly fashion in an effort to make the wiring process easier. You can probably imagine our surprise when, as we stacked the various sizes separately, we found one reel of a cable size we weren't expecting and at least one missing reel of a size we had been expecting. And this was despite us loading our own trolley at Braunston and then re-stacking it on the counter for it to be listed on our invoice. We just don't know how this mistake happened. Fortunately we had enough wire of the appropriate sizes to complete a significant part of the wiring runs and the remaining wire could be obtained when we next went to Braunston, to collect our stove and a few other items.

A few words here for our non-technical readers. Most of the electrics on the boat will be 12 volts - the type of electricity supply that you get from car type batteries. This is pretty safe and perfectly adequate for most things on a boat. However, there is a down side to this type of power supply. The longer the wire between the power supply source - in our case, the battery - and the thing that the supply is for - let's use the lights at the front of the cabin as an example, the thicker the electrical wiring needs to be. This is because all wire offers a resistance to the free flow of the electricity. The thinner the wire, the greater the resistance offered. The more resistance offered, the less power is eventually available to make lights glow or drive pumps or motors, etc. The effect is very similar to that which can be found when you pinch the walls of a hose together whilst water is running through the hose. The harder you pinch, the more resistance you are offering to the free flow of the water and the less power the water has when it leaves the hose.

Anyway, the boat cabin is approximately 45ft long. So, the total cable run between the battery and the lights is double this length - one wire out from the battery to the lights and another wire back from the lights back to the battery. The effect of the wire's resistance on some wire sizes over this distance is enough to make the difference between a bright light and a dull glow. The way to minimise the drop in available power is to use a thicker wire because thicker wires offer less resistance to the flow of electricity and this causes less power to be lost. Within the boat we have four lights in the engine room and one of the saloon light circuits has four similar sized lights. The thickness of the wire for the saloon lights is almost twice the thickness of the wire used for the engine room because the engine room lights are all within just a few feet of the battery. Anyway, enough of the physics lesson, back to wiring of our boat.

We spent the rest of Monday, apart from the odd break for lunch and a later cup of tea, running 12 volt wiring circuits. We were joined for most of the day by our friend Richard, without whom we would have taken a lot longer to achieve what we did, as one of us is vertically challenged and has some difficulty in reaching the cabin roof. The wires were threaded between the cabin roof and the spacers that we'd installed approximately every foot along the cabin. In between each of our spacers there is the foam over the metal supports for the roof. This means that the wires can only be threaded over a few spacers before it is necessary to retrace our steps and pull some more wire through.

It would be nice if all the wires ran straight along the roof - full stop! This isn't the case and, eventually, each wire and, generally, each pair (negative and positive) either has to cross the cabin roof or be run down the cabin side, or both. When this happened it was necessary to remove a small amount of the foam between metal work and underside of the batten so that the wires could be fed through. We tried several methods of achieving this but the only way we had any success was to take a bent welding rod, heat it briefly over a gas burner and then use it to melt enough of the foam to enable us to thread the wire through the hole.

Each set of wires was grouped together either with duct tape and a label, or just with the label. We'd bought a Dymo label maker specifically for the purpose and, as we used the labels, kept reminiscing about the older style label makers - the old ones that were often found on railway station platforms and featured a large dial and pointer. You put your money in the machine, spelt out your label pointing the pointer at the letters / numbers on the dial and this punched out a metal label. Then there were the more recent Dymo style labelling machines that produced embossed plastic labels. Oh happy days. Was that before they'd invented foam insulation?

Shortly after five o'clock we decided to call it a day as we'd got to a position where we'd need to start on running out the wire for another circuit if we stayed any longer and this was likely to take us some time to complete. Rather than leave a circuit in mid wiring, we pulled the plug, swept up, turned the lights off, secured the boat and headed for home.

The next visit was two days later. There was only one of us this time, but Richard was there as well so we were able to make reasonable progress on the remaining circuits. By the end of the day we'd run the wires for all but one of the electrical circuits. We had some wire left, but not of the right size for that last circuit. This was partly due to the position change for the water pump following the discovery that the water tank's position wasn't fixed when we got the boat. Our original plan had the pump under the sink in the galley but we'll free up some space there if we move the pump to under the fore deck, behind the stove. This almost doubles the length of the circuit and requires us to use the next biggest size wire.

Our original plan was for a wall mounted television on the cabin wall of the saloon, about halfway between the front doors and the dinette. We'd also planned a radio in the front starboard corner of the cabin. There would be a pair of speakers in the saloon and another pair in the galley. Then someone had the idea of suggesting that we had a set top box for the television and using the radio capabilities of the set top box instead of a separate radio. We started to think that this would be a better idea until we thought about what would happen if the television / set top box combination failed. We'd have neither television or radio. We went back to our original idea for separates.

We've hung back on running the speaker wiring whilst we investigated the set top box option so we still have the speaker wires to purchase and run now that we are going back to Plan A.

We've left the 230 volt wiring for a while. That will run under the gunwales and will be fitted there once the cabin's plywood lining is in place. This could be a bit of a chicken and egg situation. The plan is to build an inverted trough / channel under the gunwale once the hull lining is in place because the hull lining will support the upper part of the trough and form one of the sides of the trough. We'll flush mount the 240 volt sockets below the gunwale and need to wire these up - or, at least, leave the tails for the subsequent wiring - before we fit the plywood lining to the hull. However, as we need to put the wiring in the trough that is fixed to the lining it will be difficult to put the wires in the trough until the plywood panels are in position, by which time we won't be able to put the cables behind the plywood! There could be some interesting times ahead!

There is now little that we can do until the plywood arrives. It hadn't been ordered earlier because it would need to be stored within the boat and we didn't want to be tripping over 8' x 4' plywood sheets whilst we were still running wires. With the wiring basically complete we can order the plywood. Delivery is scheduled in two loads, to simplify storage. The first load is due on Monday. There is unlikely to be anything dramatic to report on the progress front for the next few as we can't see ourselves doing anything but varnishing plywood during this time.

Postscript: Within the few minutes that it took between placing the order for the plywood and writing the above paragraph, everything changed! We need a minimum of thirty sheets of plywood. 12 sheets of 12mm thick plywood for the hull sides and 18 sheets of 9mm plywood for the cabin sides and roof. Rather than try to accommodate all 30 sheets on the boat initially, we opted to take delivery of the 12mm plywood first and get that varnished before arranging delivery of the 9mm sheets. Although we checked that the suppliers had the plywood we wanted in stock a few days earlier, they have just called to say that they only have 5 sheets of 12mm plywood available for delivery on Monday. The remaining sheets of this size may not be available until the end of the month. Rather than stop work completely, we'll take delivery of those five sheets and also have twelve sheets of the 9mm plywood delivered on Monday. It will probably take us over a week to get that lot varnished, with two coats on each side. As we're planning to have a few days away shortly afterwards, the balance should arrive just when we're ready to resume varnishing. We daren't say too much now, but we could be on schedule for the basic lining to be completed by the end of a year. Note that I haven't said which year!

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