crossley

If the tunnel is properly engineered I can't see it posing any undue risk. Poor quality thin wall tube with little corrosion protection is another matter entirely, and like others have said,the wall thickness needs to be a thick as the hull. I work on tunnel thrusters as part of my job,and have had a fair few in and out, aquamaster,KaMeWa,stone Vickers,and lianenen types come to mind. They are all heavily reinforced around the propeller area,some have a sacrificial wear ring of stainless too. You do get some erosion in the tunnel where the propeller is, running, a shallow groove by the blade tips,but it's never deep,just a few mm. On supply boats and ferries they are mostly cpp propellers,and clock up lot of hours maneuvering in port or holding station on dp. Two pack epoxy is generally used and seems to last the 5 year docking periods quite happily. So given that example, a good thick wall seamless tube,epoxy painted internally, and inspected at every docking, say 2 years poses no great risk.

In a similar vein, crankcase fumes are particularly nasty,don't be breathing it in long term in confined engine rooms, it really doesn't do you any good breathing in oil mist and partly burned god knows what. Some of the older traditional engines have little in the way of any crankcase ventilation, a gauze filter,a bit of pipe etc. A small vent pipe, say 1/2" through the roof wouldn't look out of place in a "traditional" engine room.

2x 125 A/hr,24v. The tall truck type,664/665? Dead common.about £90 new. I run the tunnel thruster off them too. Works for me.

Finished engine room deckplates. Bolted back cabin stove down, lit it, warmed up a pie and boiled a kettle on it. Fitted klaxon horn. AHOOOGAAA! Love it! Painted inside some cupboards. Rain stopped play. Out for a post brexit pint tonight!

It's polyethylene. Just checked. Is that twin&earth in the pics? Looks like it. I've got a box of plastic grommets that have fused themselves to the plastic box they've been there that long.

Doing a few wiring alterations today,and have used spiral wrap for convenience behind some panels next to polystyrene insulation. I can't see any issue with this, but do bss have another view?

I was going to use batteries in the bowthruster compartment, but it's half full of ballast bricks,and I didn't like the idea of yet more batteries to keep charged,and a long way from my charging source too. Was pricing up cable from local suppliers, cef etc, and getting a fright. Batteries would have worked out cheaper, but asking around the cable turned up for next to nowt. We all deserve a bit of luck occasionally. It's suprising how people give you stuff for the boat. I was given a little generator last week,spark is very weak, and it wont start... I'll have a fiddle with it when I get home. I'm sat in a hotel bar in kokkola, Finland, bored out of my mind as you may have guessed.

Well, yes and no,I didn't want a duplicate set of batteries to maintain just for the bowthruster,and as the starter batteries have a similar short duty cycle,I decided to use them. Got a 100 meter drum of 95mm cable off a mate of mine,only thing is the cable is 600v grade heavy rubber insulated and about an inch in diameter, but beggars can't be choosers. I'm working in Finland this week,but when I get home I'll have a go at measuring the voltage drop out of curiosity. Sometimes the relays stick on mine too. Can they be dressed up or are they sealed units?

I'm using my engine start batteries to supply the bowthruster, been good upto now, I'm on 24v, have two 664? 125A/hr truck batteries in series. Batteries are in engine room and have used 95mm cable. About 25 meters out&return. Bowthruster is vetus 75kg, it takes about 200A at 24v. When measured at the motor terminals, we got about 18v, but it seems happy enough.

The wiring loom would have gone up in smoke long before an earth fault could have possibly caused the jacket water to boil.new one on me this, would take 100's of amps of fault current to do something like this,and would certainly cremate any cabling first. Two unconnected incidents and someone putting two and two together. Another case of received wisdom me thinks.

It's probably silicone grease. It's used in crankshaft dampers as the viscosity doesn't change with temperature and upset the detuning or damping characteristics.

Just a final note about the outcome of load testing my old set of batteries, they came in at between 17 to 31% of the stated 125 A/hr capacity. Broke one open today out of curiosity,just to see what was going on inside. it was full of browny red mud. S.g. Was 1.125 on all cells. Plenty of gravy left in it too. Tried charging it at 12 amps, all that happened was voltage shot up to 17 volts as it fizzed away, the s.g. Stayed the same. So the final verdict is they've shed the active material, hence the brown mud when I emptied it out. So why have they died of plate shedding? If they were undercharged they would be sulphated. If they were overcharged they would be down on electrolyte. Must be that the "cycle life" has been reached.

Looks like its going to be neither. Going looking at going looking at a two year old bank of twelve 500 A/hr chloride 2v cells on Monday. £500 cash. Looks ok, should have plenty of life left in them,just hoping they will outlive a new set of Trojans or whatever.

Yes,it's battery decision time once again, I've been playing all the usual suppliers off against each other as you do, and have got the prices down for 4 off 6v batteries as follows, Trojan l16 @ £255 each Crown cr430 @ £218 each Us batteries 16p @ £202 each. That's inc vat&delivery. Don't think I can squeeze any more out of them on price. Thing is, are they all much the same, or is any one brand far better? The crowns are heaviest at 55 kg. Anyone any direct experience of these, any horror stories or recommendations? Need the taller style battery as takes up less floor space. So,which to snog,marry,or avoid? All of there websites seek to big themselves up and rubbish the competition in true transatlantic style. Don't we make big 6v batteries in the UK now?