>... issue of flooding the engine with water (hydro lock) by the following seas.
This happened to me on a delivery from Hawaii to Seattle. The boat is a custom 46' that was a bit tired from many trips between New Zealand and Tonga. I flew into Honolulu with my delivery crew to take over for the owner who sailed it from Tonga to Hawaii. Before departing Honolulu I did notice some engine starting and idling issues mostly related to the high hours and low maintenance. As it was Labor Day weekend I could not arrange for a competent diesel mechanic to visit the marina and the crew's time commitments were counting down. I decided that it should be OK and to quote Cap't Ron "if anything is going to happen, it'll happen out there boss". The exhaust riser/vent loop brackets had failed allowing the exhaust hose to lay below the water line when heeled on a stbd tack. Two days out of Honolulu sailing on stbd and charging the batteries the sea water pressure overcame the weak exhaust flow (failing valve springs and other compression issues) and the engine stalled. Not knowing why I attempted to re-start and the sea water from the water lift muffler backed up into the engine to create a hydro lock. We were able to affect repairs enough to recharge batteries, refrigeration, and motor very slowly in light air. The NE Pacific of September of 1993 had a lot of light air. The boat did get to Seattle but it took 23 days not the 15 to 17 planned. Fortunately the fishing was good so we had plenty of food, we had just enough fresh water, and had lots of diesel left over. Vent loops in any hose that discharges near the water and keeping the exhaust hose higher than the heeled water line are a good idea. A good check valve in working order may help prevent bilge flooding from a syphon but having and maintaining the vent loop(s) add an extra safety margin. Martin DeYoung Calypso 1971 C&C 43 Seattle [Description: Description: cid:D1BF9853-22F7-47FB-86F2-4115CE0BAF2F] From: CnC-List [mailto:[email protected]] On Behalf Of Marek Dziedzic via CnC-List Sent: Friday, May 22, 2015 9:01 AM To: [email protected] Cc: Marek Dziedzic Subject: Re: Stus-List Check valve on bilge pump If I were you , I would install an anti-siphon loop first and then think of the check valve. Most of us don't sail in really heavy weather conditions, so this may not apply, but I read somewhere about an issue of flooding the engine with water (hydrolock) by the following seas. The guy ended up installing a manual cut-off valve on the exit of his exhaust to prevent it. I guess this would make sense only if you are making long enough passages. Marek 1994 C270 "Legato" Ottawa From: David Knecht via CnC-List<mailto:[email protected]> Sent: Friday, May 22, 2015 9:12 AM To: CnC CnC discussion list<mailto:[email protected]> Cc: David Knecht<mailto:[email protected]> Subject: Stus-List Check valve on bilge pump We had a discussion a few years back about whether or not to have a check valve on the bilge pump outlet hose and as a result, I removed the valve from mine. All has been fine since. Yesterday, while motoring for a long ways down the river, I noticed that the bilge was filling with water. I pumped it out and the water immediately returned. I pulled the pump out of the bilge, and water was pouring into the bilge through the pump. When I lifted it, the flow stopped so it seemed to be siphoning/flowing through the bilge pump exit line, which is in the transom and when motoring, looks to be under water. I have not checked yet to see if there is an anti-siphon loop. I am guessing that this is one of the functions of the one way valve that was there before, but I can't figure out why it never happened before. The Whale 500 pump does not specifically say it has a check valve, but perhaps it does and it stopped working? I had an oil spill into the bilge last winter and so maybe that is causing problems. I plan to reinstall a check valve in the line so this does not happen again. Any other thoughts? Thanks- Dave Aries 1990 C&C 34+ New London, CT [cid:[email protected]] ________________________________ _______________________________________________ Email address: [email protected]<mailto:[email protected]> To change your list preferences, including unsubscribing -- go to the bottom of page at: http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com
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