Radiomariner

I thought I had made it clear the size of the hole does not necessarily determine the ventilation. I did not mention Vetus vents. I am annoyed that you linked my comments to a particular manufacture. I was talking about UFO vents in general, and some of their problems. Tannoy is one one make (I cant at present recall other makes to hand). I have not had a Vetus vent apart but from information I have seen Vetus vents seem to have a slightly higher free airflow than the others. I would be interested to know the manufacturer and model your UFO vents are.

With the IT on the boat there is still a possibility that lead from the shore power point may chafe against part of the boat structure causing the hull to become live. In a properly installed marina this should cause a shore RCD to trip. How good is the shore installation? Some boaters therefore put the IT ashore to avoid this risk. Personally I would prefer an IT but expense and space on my wee boat do not permit it. I have a GI instead.

Yes. I forgot to mention dead flies and spiders. Might I add a warning here: = To boaters who have a nice expanded metal decorative or mesh type grill keeping spiders etc. out. The ones in the vicinity of the galley are particularly prone to blocking up due to airborne grease particles from cooking. Keep 'em clean.

Sorry Keep Up, the BSS must assume the possibility that at some time the fan may not be working. Electric motor failure, battery failure or anything that stops the fan rotating. The fan blades then are simply an obstruction to free air flow. I normally discount such a vent from the calculations unless there is a shortfall where I will then include it with a reduction of 25% along with any gaps around doors etc. in order to avoid a "Yes, but........." on the exam Report.

Depends a lot on where you moor, The blocked ones I have seen have been blocked by what I believe to be leaf mould, combined with blossom from trees (elderflower for instance) which is very prolific in many areas. It turns into a gungy mess. All the drain holes do not have to be blocked to let moisture enter. If the ventilator is to one the side of a curved roof, it only needs the lower ones to block.Quite a few of them leaked not into the cabin but to the space between roof and roof liner Had a chuckle at you never having leeks. I imagine big green Welsh vegetables forcing their way in like Triffids. Edited 'cause I can't spell (and still can't) Triffids.

100mm dia. hole alone would provide 7850 sq. mm of free ventilation. It is what is above, that limits the ventilation. In the case of mushrooms it is the gap between the shoulder of the vent-shaft and the mushroom dome that is the controlling factor. Outside diameter of mushroom shaft say 100mm minus thickness of shaft material say 3mm leaves an internal diameter of 94mm multiply by Pi gives the circumference 295mm then multiply that by the size of the gap say 1 inch (25.4mm) = 7493 sq mm of free air ventilation. To half the gap reduces this figure to 3746 sq mm. This of course may be further reduced by the inclusion of fly screens. UFO type vents are basically mushroom vents with a covering protective dome and the ventilation gap is under the edge of the mushroom and a channel (drain) below it. The circumference ot the mushroom is of course much larger but the gap is considerably smaller, 2 or 3 mm. A very fine mesh fly screen can reduce the ventilation further but this ventilation loss may not be proportionate as it is generally fitted in a location much wider than the 2-3 mm gap mentioned. These vents are prone to blocked drain outlets that may not only reduce the ventilation but let some water into the boat. (The drain fills up and overflows) Regular cleaning out necessary. Edited to add: - The free airflow of UFO vents can be increased considerably by dismantling and re-assembling in a fashion to increase the gap by i or 2 mm . Some might need spacers to lift the mushroom top, others might need a couple of mm to be cut off the plastic mushroom skirt. Whatever you do details of your modification, such as a simple diagram with dimensions will help convince the BSS Examiner

I've seen explosion like this before. Much bigger battery for starting a large emergency generator. Cause was never fully investigated, but it was believed that the electrolyte level in the battery had been maintained at too high a level allowing part of a bus connecting the cells to corrode, eventually thinning enough so it ruptured like a fuse. Resulting spark ignited hydrogen. I always preferred the older batteries that had nice big solid connecting bus between cells on top of, rather than inside the casing.

Matching prop size and design, to engine speed, for fuel efficiency to me is a 'black art'. A supertanker (VLCC 300000 tonnes) spent most of it's voyages running at the charterers requested speed which was not very efficient. It took months for the boffins to figure out what changes had to be made to the prop to improve this. Ship went into dry dock, the experts arrived with all their laser devices and grinding tools. Took about five days to change the shape of the (very big, size of a small house) prop. Result, vast improvement in engine efficiency. However, the clever boffins had not looked at the bigger picture. Waste heat from the engine exhaust is used to generate steam to heat the fuel oil for the engine, (when cold, a bit like tar), with the newly efficient running engine there was not enough waste heat to do this. We had instead to run a boiler to generate steam! Tremendous loss in efficiency resulting.

And a Bonny boat

Did you anneal the copper washers before putting them back? Edited to add: You may be unfamiliar with this. Heat washers over a gas flame until they glow brightly.and allow them to cool before refitting

Although prefixing the name with "The" sounds grand on say "The Queen Mary" or "The Majestic" it indicates these are special vessels,but completely stupid on Kingfisher. there are so many of them!. My boas named "Peppers Paw" would not sound right at all prefixed with "the". By the way, I have given up exlaining that Pepper was a very much loved dog tha loved running up and down a narrow boat, I now answer the question "Who is Pepper?" with, jn as strong a Scots accent as possible, "My Daughter"!

Seafarers, working for Amoco would have referred to it as "The Cadiz" All the ships in the fleet began with Amoco.

Thats what a lot of boaters (a minority I might add) do. Your suggestion is however about as far away from tne common sense approach as is possible Exactly

Perhaps it is because the fridge is likely to be on 24/7 and possibly not switched off when vessel taking on fuel. Personally, I would be alarmed if I found such appliances (solid fuel and catalytic) on boats with petrol engines. I can not vouch for other examiners, but finding such would prompt me to contact the BSS office for advice. If the advice is that it's ok I would put comment in the examination report. It's called C.Y.A.

http://www.boatsafetyscheme.org/media/194782/2013ecp_private%20_boats_ed3_public_final.pdf section 8.2.1

Or requires tools to shut

Not Correct. Probably true Read it more carefully. That applies to Petrol driven boats No secret. The full Exam procedures are available on the BSS web site.

Yes. The BSS is aimed mainly at "Third Parties" A BSS advisory means that the owner (Who s responsible for the boat's safety) is fully aware of the problem and should he wish to risk the life of not only himself but that of his family and friends he is perfectly at liberty to do so. On the other hand, Hire and commercial and some "share" boats, where the boat users are not responsible for the level of safety on the boat, have a different set of rules wherein ALL the BSS checks are MANDATORY. Edited to add: God forbid, but should there be a mishap due to an "advisory failure" item Insurers are likely to deem the owner responsible and refuse compensation. It is also possible that having had documented advice that has not been acted upon, the insurers can also assume a poor level of maintenance and consider the owner to be responsible for any mishap.

Someone else's battery or someone else's spanner? Perhaps both! Thermal runaway. SWMBO claims that is what happened to my winter 'long johns'. Personally I don't think she could be arsed dhobing them.

Enthusiastic fornicators rock the boat. Ear plugs do nothing for that!

Measuring by dipstick involves a lot of factors in addition to known tank measures. the boat's trim for instance would have to be taken into account. I don't think the average boat yard attendant would be up to this. I can however envisage a yard using a dipstick when filling a tank to stop the filling at a predetermined level (say 90%) to avoid overfilling and overflowing. The pump would be stopped when that point is reached and the (calibrated) pump reading taken to calculate fuel used. Tip, for the original poster. If the water tank is forward and the measuring point for the fuel tank (be it the filling point, a separate dipstick aperture, or a float device) arriving back with an empty water tank MAY be to your advantage, and a full water tank if the devices are at the forward end of the tank. Depends whether the hirer fills the water tank before the fuel tank

Next time you nick yourself when shaving, ask yourself, "did this blade come from a holding tank?" Then reach for the antiseptic! I have examined quite a few boats that have been rescued after being Section 8'ed, Some sold at a very tidy profit.

As most boats sit slightly lower at the stern for much of the time, rainwater gathers between the hatch rails and flows over the hatch-combing. Depending of course on the design of the hatch, the answer may simply be to drill a couple or holes through the slider rail support to allow water to drain away down the roof.