Hey,
This article (goodoldboat.com/cool-quiet-and-trouble-free-exhaust/) states that a scoop on the raw water inlet may lead to flooding of the engine when sailing due to the fact that "Six knots produces about 19 inches of water column pressure".
Anyone had any problems with this? I've just had new engine installed. Have motored but not sailed yet. Noticed the manual states that they should never be used, yet the installer didn't think it was an issue.
Cheers,
Roger
Are you sure he installed a scoop?
You could turn off the valve when you shut the motor off and sail. I would be looking for a new "Expert".
Thx Ramona. Scoop was existing from previous install (which was a drofin 12, which did have seawater ingress but of cause unknown).
Yes, seems I will have to turn off seacock under sail and back on when I need the engine, which is a bit trickier short handed. Is it right to assume that it would be preferable to run the (heat exchanged) engine for a minute without water rather than have a minute of sailing with seacock on and engine off (when switching from power to sail)? So on mooring: seacock on, start engine, raise sails, seacock off, engine off. Back to mooring: engine on, seacock on, douse sails. Sound okay if it's 30 seconds to a minute?
As a person new to sailing and to boat ownership, it really pisses me off that mechanics and "shipwrights" either don't know basic stuff or don't care. Yes, I know that I'm the skipper / owner and I'm responsible but I don't yet have all this knowledge and I have expected other people with knowledge to do the right thing. She was up on the hard for 10 days for the install (much of that waiting for parts) so there was plenty of time to do a job like this. And it would have made them money - they certainly can't be blamed for hard selling! /end rant
Anyway, I'm glad to have this and other forums and also the god-send, This Old Boat.
The raw water inlet goes thru the sea strainer then into the engine via the water pump the impeller in the pump will limit the water pressure, which i have never heard of this issue before.
I believe this is miss-information and a little bit of Bullsh.t on the manufacturers part.
Love your Adams 31 as I love my Adams 35
Don't really have this problem as I have a heat exchanger on my Nanni
But, you should turn your seacock on; then start your motor/turn it off, then turn the seacock off.
Why, because you will run the impellor dry without the seacock open and that will ruin the seal and it won't work!
Whiteout is correct in that the impeller stationary will limit the water pressure, the scoop which sounds like its the type installed on motor vessels will not scoop up much water anyway, how fast can a Carter 33 go? Flooding of an engine occurs when there is too much water in a water muffler and it comes up the exhaust and into open exhaust valves. If the difference in height between the valves and the muffler is enough or an anti siphon valve is fitted and working then it should not occur. However how this works when the yacht is heeled I don't know. With a scoop it seems to me eventually the exhaust will fill up to the height of the exhaust outlet. If this is lower than the cylinder head then you may get away with it. I would be inclined to follow the manufacturers manual. Next time you slip cut the scoop off with a mini grinder.
My engine key has a tag and it hooks over the inlet valve. To start I pick up the key and open the valve start the engine. Shut down I pull the decompression knob, turn off the key and pull it out and hang the key on the valve as I turn it off.
The raw water pump impeller has to stay wet!
