Iain_S

I'd call these machine screws. Wikipedia set screw definition

However, there is a "get out" clause . (My Bold)

Our shower drain and the drain down for the calorifier go into a small tank which is piped to a Whale Gulper pump, controlled by a float switch inside the tank. It's proved fairly reliable, although I have had to replace the float switch once.

We were similar. I was one of six friends who hired a narrowboat in the late 70s . At that time, hiring was relatively cheap when split 6 ways. Several years later, my wife and I were discussing what to do for a holiday in October when we both had time off work. Neither of us is a fan of lying on a beach getting sun tanned, and there was the problem of what to do with dogs while we were away. I suggested canal boating, which didn’t go down well. About a week later, I suggested trying hang gliding, and canal boating became much more attractive! Following that, we hired for a few years, but got a bit upset when the second week of a two week hire was double the price of the first week, due to a bank holiday. We spotted an Ownerships advert , and bought a share in their cheapest boat. That worked, and so we enquired about shares in their larger boats. None of the ones we looked at appealed, but Ownerships bought a trad. boat, and we bought a share in that. We gradually increased our share (there was a policy of current owners getting first refusal if a share was sold) and that was holidays sorted for many years, until Ann (the aforesaid wife!) noticed that a boat owned by a friend was still for sale. We bought it …

... or 1/6400 of 360 degrees!

Really old ones hold 5 gallons. Modern ones are slightly smaller, and are full to the neck at 20 litres.

Dalmuir Drop Lock on the Forth and Clyde. It's a bit of a monster, really. The water has to be pumped out of the lock once the boats are in it. Takes about 40 minutes, assuming the inflows to the pumps are reasonably clear and not blocked by weed. Used to be a bit quicker, when the operator was able to drop the lock just enough to get the boats under the bridge, but it now has to go all the way down for H&S reasons. If building another one, a big improvement would be the provision of a reservoir below lock level, so that the lock could be emptied using paddles rather than a pump. You'd still need pumps to empty the reservoir back into the canal, but you'd get away with lower pumping capacity and the lock operation would be a lot quicker.

You can get a replacement display for the hours meter on the tacho. Fitting is a bit fiddly, mainly due to having to remove the front "glass" on the instrument.

Gibbo's explanation Go to DC with no AC on board.

A vintage engine would not meet emission requirements, and so the boat would have to be a replica of a historic vessel. Bear in mind that, unlike other boats, class D ones can be RCR self certified by the builder. Ours has RCD certification, but definitely does not meet the regulations, and I suspect most builder certified ones are similar.

I’m not familiar with centre cockpit Sea Otters, but they are based on the same hull arrangements as the cruiser stern ones. I assume that the rudder tube is in the same place as in ours, but cut short so that it doesn’t extend to the back deck. If that’s the case, then it wouldn’t be possible to fit the rudder arm backwards. Your other suggestions could work, though. Definite head scratcher!

That was used on the Forth &Clyde canal. There were shallows at the start points at stables (slower wave speed) to aid this. The boats were towed by a team of four horses, supposedly at the gallop, but I suspect a canter would be nearer the mark.

But cabling includes the cables within the appliance ...

40A blade fuse is standard. Usual failure mode is overheating due to bad connection in the fuse holder, so that both fuse and holder need replaced.