Some questions from a newbie

AntarcticPilot said:
It is worth remembering that it is impossible for the temperature of the water round a floating vessel to go below zero, or perhaps a degree or two below for salt water.
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Bear in mind that many moorings and marinae are in estuaries where - especially in winter with heavy rain water drainage - the water can become distinctly brackish, and freeze at unexceptional temperatures. I saw ice on the Hamble two years ago, and Dylan Winter has a Keep Turning Left film where he's woken by ice bashing against the boat as it refloats on the flood.
 
Searush said:
Err, that's in the UK. It's a bit different in other countries - like Canada, N USA or Baltic & Northern Russia of course.
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Well, yes - my username and my avatar are clues to first-hand knowledge of this! But I think that anyone venturing into waters where this is an issue will probably be well aware of the necessary precautions to be taken. And even in Antarctica, the sea is MUCH warmer than the air.

Twister_Ken said:
Bear in mind that many moorings and marinae are in estuaries where - especially in winter with heavy rain water drainage - the water can become distinctly brackish, and freeze at unexceptional temperatures. I saw ice on the Hamble two years ago, and Dylan Winter has a Keep Turning Left film where he's woken by ice bashing against the boat as it refloats on the flood.
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Actually, this helps - salt water can become colder before freezing than fresh can. So, fresher water = higher water temperatures while it is still water! And it is very unlikely (in the UK!) that you would get enough thickness of ice to make a difference; the majority of the hull will be in water. You'd need ice at least a foot thick to make much difference, and if the ice was that thick, you'd be worried about the boat being damaged by the ice. Ice in contact with water is at the same temperature as the water unless it is thick enough to have an insulating effect - which would be vanishingly rare in any tidal waters in the UK.

As I noted, it happens that the marina I am currently in does freeze on a regular basis; the temperature of the boat is still higher than the air temperature.
 
I know a lot of boat owners, admittedly inland, who don't bother taking any precautions at all apart from regular visits to put a bit of heat into the boat, run the engine etc. Most narrowboats, for example, have raw water cooled engines and there are many I suspect don't even bother with anti freeze in the heat exchanger, I've certainly never heard of anyone being concerned about purging the river/canal water from the system. I saw loads of boats left unattended all last winter with 4" of ice around them cruising away happily when the spring finally came.
I don't think many people bother draining their water tanks either, but I wouldn't risk leaving a boat through the winter without draining down the pipes. (The old Paloma water heater which is still in service on many boats is a particular weak point.)
 
Be careful with the compressed air! If the engine has stopped with one of its exhaust valves open (or slightly open), I guess you could run the risk of blowing some salt water into the combustion chamber.

My raw water cooled engine manual tells you to run a bucket of fresh water through it, then a 50% antifreeze / water mixture and just switch the engine off as soon as the mixture starts coming out of the exhaust (i.e. just a few seconds). I think it's probably better for them to sit full of antifreeze with their anodes in place than it is for them to sit empty, because even if you could get absolutely all the water out, you'd be bound to get days when condensation formed on the inside surfaces of the block.
 
Avocet said:
Be careful with the compressed air! If the engine has stopped with one of its exhaust valves open (or slightly open), I guess you could run the risk of blowing some salt water into the combustion chamber.

My raw water cooled engine manual tells you to run a bucket of fresh water through it, then a 50% antifreeze / water mixture and just switch the engine off as soon as the mixture starts coming out of the exhaust (i.e. just a few seconds). I think it's probably better for them to sit full of antifreeze with their anodes in place than it is for them to sit empty, because even if you could get absolutely all the water out, you'd be bound to get days when condensation formed on the inside surfaces of the block.
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I didn't use compressed air but I did remove the water pipes top and bottom and blow through with lung power. It wasn't that effective to be honest but gravity had already done most of the work so I was blowing against an open end. I did wonder if I had done enough but thinking about it a bit of water freezing in the bottom of a water channel is much less likely to do any damage than a full water jacket with nowhere to expand to. I don't worry about condensation freezing at all.
 
aquaplane said:
I didn't use compressed air but I did remove the water pipes top and bottom and blow through with lung power. It wasn't that effective to be honest but gravity had already done most of the work so I was blowing against an open end. I did wonder if I had done enough but thinking about it a bit of water freezing in the bottom of a water channel is much less likely to do any damage than a full water jacket with nowhere to expand to. I don't worry about condensation freezing at all.
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Thinking it through, it must be better for the block to be as full as possible with antifreeze mixture (which is also a corrosion inhibitor) than empty and damp, with the certainty of (at least) surface rust forming over the lay-up period.
 
Another newbie question

Man in Cornwall looking for an engine for his newly-aquired 23` sloop (1960)
Yanmar 10 is all the info. I have for this search on his behalf. Any pointers please? Many thanks sailors.
 
The For Sale columns and Wanted are the usual places for these enquiries, but the price limits preclude them being advertised there.
You would probably get a better idea on Ebay, the internet auction website, for a direct offer, however enquiries in this forum about the suitability of engine to boat types often elicits plenty of opinions and possible sources, assuming you are looking for a secondhand unit.
If a new engine, then a Google search for the 'Yanmar 1GM10 'will show many of the main dealer sources country wide.

You should start your own thread here for any further information from the forum as it is considered impolite to use someone else's thread for a question of your own.
Start the thread with a title such as " Yanmar 1GM10 search",then others can help that enquiry for you.

ianat182
 
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