Tony Brooks

good point Mr G. I forget that some have an aversion to revving their engine a bit when starting.

Personally I would want someone who has done it to confirm that. I understand the odd 70fotter narrowboat has got stuck there.

And would a 57' wide beam get around the sharp bend on the Ribble link?

Typically a faulty alternator or faulty oil pressure/ engine temp. sender. Is it charging properly? If no lights are on it could be a cable to either sender shorting to the metal of the boat. look for trapped or chaffed wires. Always be aware that although such senders are not very reliable there os always a slight chance t really is low oil pressure or an overheat.

Ideally two vents, one at either end of the tank of a large diameter. I would say 1.5" or more ideally although the one I added to my tank is only 22mm. They should be as near horizontal as practical but the "freeboard rules" may involve an upwards slope. Certainly not a vertical and then an elbow if it can be avoided. During the really hot weather in late May/June I had no end of smell but as soon as the weather cooled down it is far better. I mechanically ventilate the one vent using large brushless computer fan in a DIY steel box sucking out. Be wary of any hoses that allow effluent to sit in them. Pump out hoses can and do allow smell to leech through the walls, especially low quality ones.

When the new tap also fails I think I would fit a push button switch to turn the pump on and off (like a car's horn push or starter button). Long term that is likely to be more reliable. They will often fit in the front of the sink "unit" so its right by a raised knee.

Units again - 15 Amp hours per day I assume. If its true it is very good, especially when you consider the inverter overhead.

I expect SAE 15W40 will be fine in API CC or CD if you can find it. Otherwise API CE or at a push CF, CF will be easier to find but depending on how you use the boat just might cause the bores to glaze over time. MY feeling is that as long as you thrash it now and again and never charge on idle CF will probably be fine but do not hold me to that. SAE 30 or SAE 20W50 should also do the job in the above API grades.

If this helps. On displacement boats the maximum speed is governed by wave making and as soon as the stern drops into the trough of the bow wave the hull will simply not go any faster, you just burn more fuel making ever bigger waves. Also water resistance goes up by the square of the speed so doubling the speed increases the water resistance by four. I have put your length (21 ft as the waterline length) into formula for maximum hull speed for displacement craft using 1.2 as the hull constant ( we do not know what your hull constant is but about 1.2 to 1.3 is unlikely to be far off the mark). This gives a maximum hull speed of just over 5 knots (5.7 mph). This is in free open water, it will be worse the more restricted the channel. Because we do not know your hull constant I suspect that you might be over driving the boat and wasting fuel.

Note what Loddon said above - If you follow the instructions from Cuthound any reading you get for current on that meter will be garbage. Get one that is probably rather more ex[pensive that states it measures DC amps and then the instructions are correct - well they are correct anyway but you will not be able to set the range for DC amps on the one linked to because it does not have one. It is not clear that you know the symbols used to signify AC and DC.

Typically the header tank, which is also the heat exchanger and possibly the exhaust manifold as well, is topped up to about 1" below the bottom of the filler neck when COLD. this is to allow space for the coolant to expand when heated. NOTE TO OTHERS - this is not correct for tank cooled boats. If you overfill it all that will happen is some coolant will be blown out as it heats up. If the engine is not boiling with clouds of steam and water spurting from the filler cap it is almost certainly running at an acceptable temperature. Temperature alone rarely causes leaks. Lip seals work by pressure forcing the lip against the shaft. As the engine heats up the cooling system shoudl become pressurised, that will help force the seal lip against the shaft. As it cools down the the pressure drops so a worn lip may start leaking again. It all sounds consistent with a worn seal but with the raw water shut off valve shut with the engine stopped the drips should stop once the raw water in the pipes has drained out. You have been loosing antifreeze so check the strength, the vital thing abuout antifreeze is that it helps to prevent corrosion inside the engine..

Where is the pump relative to the water line on the boat. If below then turn off the sea cock and the drip should stop. If its above it will drip until any raw water in the higher parts of the engine have drained. If it only drips AFTER topping up the cooling system header tank then it is a heat exchanger problem but I would want to see the heat exchanger before I can suggest what it might be. There is not a coil inside but a bundle of tubes in brass end caps. How the end caps are sealed between raw water and coolant depends upon the design of the heat exchanger so that is why I need to see it. If its dripping raw water then remember you are filling the bilge and the drip might get worse. If its the coolant and you do not keep it topped up then the engine will overheat with all that may lead to. As long as you understand that and act accordingly it should be fine - my boat has a dripping seal in a simmilar pump since last summer and its fine as long as I keep it topped up with antifreeze mixture.

It is a heat exchanger system and the pump is one with bearings in it. I can not see enough of the area above the pump but I would say whatever the blue thing above the pump is it does not seem to be sitting square - that could well be a leak area.

The exact design of that raw water pump varies so to be a little more positive about what pump you have I need to know if it is direct raw water cooled or indirect raw water -heat exchanger cooled. In general there is a gap in the body casting that contains a rubber thrower - this is what I think you are calling a loose rubber O ring except it is more like a rubber washer. There should be absolutely no way for blue water to get there unless its a heat exchanger boat and there is a leak inside the exchanger but as you do not mention continually topping up the fresh water part of such a system I feel this is unlikely. The shaft in the pump may be running in the pump body or it may be running in ball type bearings. In either case thee needs to be two oil seals. One to keep oil in the engine and stop it leaking down the shaft ad the other to stop water leaking from the impeller chamber. The rubber washer is to spin either oil or water away from the shaft. If the shaft is running in the pump body then in all probability the body is worn oval so you are now unlikely to stop it leaking. If its running in bearings then new bearings and two new seals should sort it. The pumps with shaft running in the body tend to have a grease cap on top, insufficient use of this leads to the wear I describe above. If you are really lucky and as long as the shaft has no significant radial play then just a pair of seals may be all it needs. With such old engines you may find the seals have worn a groove in the shaft. If so the new seals may not last long and a new shaft it probably the best way forward

I think what Neil2 says needs emphasising, especially for anything other that a narrowboat. The ridge arch or the slop of the deck on a flat "arch" bridge or even how a bridge sits in relation to the canal may well mean the airdraft of a boat would need to be lower than that stated. I understand that some bridge abutments have moved over the years thereby forcing boats to one side of the bridge hole. This limits the available airdraft for wide beam boats but much depends upon the boat's profile. Then there is the water level on river navigations. A boat may pass under certain bridges for several months of the year but may not when the level rises. My advice is to treat any such dimension as a very rough guide until you have physically checked.