Timleech

My admittedly very hasty reading suggests that there is a prohibition on emitting 'dark smoke' as per their definition from railway engines and vessels, but not 'smoke', whereas for FIXED furnaces/fires in smoke control areas NO smoke is permitted. Tim

AIUI you're OK with any stove provided you're using an inherently smokeless fuel such as anthracite. The 'approved appliance' bit comes in for other fuels, including wood apparently. 'portable' stoves are usually cited, rightly or wrongly, as giving exemption for boats. Not sure about boats which never move, though Tim

You may be able to get it out by moving the propellor shaft backwards, if there's room before it hits the rudder. Tim

DON'T SHOUT!! Looks like a Centaflex, there's probably a 'ring' of maybe 6 or 8 bolts around the shaft & parallel with it. These pull a tapered sleeve up inside the coupling. Slacken these off, you may need to slack them all a turn or two & then tap the heads to release the taper. I'm not an expert on these, though, but I expect someone will be along in a while who is. Tim

Surveyors will often give a verbal yea or nay, or a list of serious faults, on the day to prospective buyers.Regarding wire brushing, I'm not in favour *unless it's really needed*. It tends to smear old paint around, and polish the surface, so reducing the adhesion of new paint. We'll often (power) wire brush around the waterline if there's rusting, but confine it to the rusted areas, or for heavier rust use an air chisel or needle gun.Otherwise, a powerful pressure washer with rotary nozzle leaves the surface good enough for blacking.I'm not a fan of primers under blacking either, most do more harm than good and even the recommended ones don't seem to allow the blacking to adhere as well as it would to parent metal.Tim Our 'standard treatment' © is one coat of Premium Protection, one coat of Rytex up to & including the waterline, and a final overall coat of PP.The theory (mine) is that the PP is easy to use as a first coat, to work into pitting etc. The Rytex builds up a decent thickness of coating. The top coat of PP is harder than the Rytex, allegedly diesel resistant, and as a bonus is nice & shiny ;)They're both Bitumen based, so are compatible with one another. Tim

Are you quite sure it wasn't a mink? Tim

Well it's a pretty awful one IMHO I'm fairly sure I read somewhere that the application was supported by BW. Tim

What an awful website. The only way I can make the documents at all useable is to copy the images & open them in something else Tim

He used to regularly have a dig at the ukrw newsgroup, which IIRC he constantly referred to as a 'site', as though it was in some way competing with nbw and he was desperate to show that nbw was 'better' than ukrw. Maybe he still does, but I haven't looked at nbw for a long time. Tim

It is, as others have said, the Uxter plate, and absolutely nothing to do with Rosie & Jim (cringe) I see a lot of nb's out of the water for blacking & other work, very few suffer serious external corrosion in this area. What is very common, though, is serious internal corrosion from, as you say, leaking deck drains, also just from condensation which collects & can't drain away. Actually a cement wash might be a good way to protect this area Bilge areas of barges are/were often protected in this way from new. Tim

Am I missing something? The power and torque curves for the two engines are very similar shapes, and both around 25% higher for the 4.17 Tim

I was surprised to see how much the wide-beam Bantam tug went for, about 7K +VAT if you include the fees. JP3 engine, probably basically OK, but with a dodgy gearbox. The Badger isn't as bad as it might appear. These dredgers were designed with lightweight GRP superstructures, to keep the weight 'usptairs' to a minimum. BW in their wisdom re-cabined some, including Badger, with heavy (6mm & up, allegedly) steel cabins which not only makes them sit lower in the water but also makes them less stable. I recabined one for them a few years ago with 3mm & 4mm steel and fairly light insulation/lining, that wasn't too bad. Parking the back-actor arm in the water like that is the normal & safe thing to do. Tim

Maybe the rudder post is bent? Tim

But remember that the Power/rpm curve for the prop will be approximately y = x cubed Tim

These graphs are relevant in the motor vehicle situation, where they give a fair indication of what the engine will produce at different speeds when the throttle is wide open. Their only relevance to the marine propulsion situation is in determining propellor size. Once a given prop is fitted, any torque at speeds below max is irrelevant for reasons already discussed. Tim

Maybe true in a sense, poor combustion due to less than perfect injectors, or possibly lubricating oil being burned in the cylinders. Is the exhaust noticeably smoky? blue for oil, dark grey/black for poor combustion. My HR/W book says the operating temp should be between 75 & 90 C. The lower temp might make a small difference to the exhaust, a bigger difference to things like oil sludging. Tim

The torque available from the engine does indeed usually reach its maximum below max rpm. The torque required to turn the propellor, however, increases with the square of the rpm and therefore must, absolutely, be at its max at max rpm. Tim

A couple of minutes with Google comes up with the range of Bitumastic products:- http://www.spencercoatings.co.uk/index/products_bitumastic It looks as though Spencer Coatings have just about collected all the well known UK brands for hull coatings etc. Tim

Bitumastic is a TRADE NAME , used to be that of Wailes Dove though I'm not sure whether they still exist but somebody uses the name. They supply both coal tar and bitumen based products. Standard Black is or was possibly their best known product, it is coal tar based. They used to also supply coloured 'Bitumastic' paints, I think these were probably Chlorinated Rubber paints.

The crucial thing to remember is that the engine will only produce the hp & torque that it's called upon for, up to the level of which it's capable. Also the torque required to turn the propellor goes up roughly with the square of the rpm (and the power by the cube). This means that, unless you have a fouled prop or some such, maximum torque and maximum power will both be at the maximum rpm for that particular engine/prop combination. Suppose, for the sake of argument, that your engine is using 1 bhp to turn your prop at 1000 rpm, at 2000 rpm (double the speed) it will need 2 x 2 x 2bhp = 8 bhp (two cubed) to turn the propellor, and at 4000 rpm it will need 64 bhp (eight x [two cubed]). If it can't manage the 64 bhp, it won't reach the 4000 rpm. I hope that's right, I was horrified to realise how rusty my maths has become Tim

Coal Tar/Pitch based paints used to be commonly used, including the 'Standard Black' mentioned above. There are more H&S issues with coal tar products than with bitumen, so they're less readily available these days and less commonly used. They do, in general, last longer than Bitumen-based paints. Usual recommendation is docking every 2 to 3 years with Bitumen, 3 to 4 years with Tar paints, though the safest way to decide is to keep an eye on your own waterline. Comastic & Coflex are coal tar pitch based, they are not compatible with bitumen paints. The solvent fumes are pretty unpleasant, too! Tim

Basically, yes. Usually the weight is taken on the skeg, that is generally preferable. Some cases of 'rudder rattle' can be traced to the weight being taken - either by accident or design - by the upper bearing, leaving the post free to flap about in the skeg cup. Tim

Believe me, I'm no particular fan of the current shiny floating cottage style, but some of these older boats really are getting past their use-by dates. Not all, there are decent examples from the period which are definitely worth keeping, and spending money on when needed. Tim

As a general principle I agree, but you obviously haven't seen the amount of rusty junk on the dry-dock that I have Tim

Nowhere near enough. People will continue spending money to keep an old tub afloat when to me it doesn't seem rational, if it were a car it would have been crushed long ago - except that the old tub still seems to have a 'value' which makes patching it up ad infinitum 'worthwhile'. I'm sure that'll change if secondhand prices drop significantly. There are quite a few boats around from the sixties and seventies, the days of 1/4" bottoms and wet bilges, which have IMO reached the end of their natural lives. Tim