How does a one-way thru hull valve work? I have a pipe sticking thru the front of my sailboat with a cork in it and I'm nervous it could spring a leak. Is this a possiblity? Also, my sink has been clogged for days and I'm not sure if I can detatch the hose to unclog it without sinking my boat. Anyone know how to care for these valves?
One way valves
- Thread starter HNL Beagle
- Start date
- Status
Never heard of a cork before except on my dinghy
What's the year, size and make of your boat? My dinghy has a rubber cork on the stern, but that is for another purpose altogether. I have never heard of using a cork on the pipe at the bow. But that could just be me. As for your sink drain hose, the hose should end at a thru-hull seacock. You should be able to just close the seacock, and then disconnect and work on the hose. If there is no seacock, then I would start to worry. I can't imagine a production boat without using a seacock. If the seacock is not easy to turn, or won't turn at all, then be very gentle. It could've rusted or corroded shut, If you force it, you may end up braking parts of it off then you will have real trouble. If this is the case, then you should wait until you haul the boat to fix it.
What's the year, size and make of your boat? My dinghy has a rubber cork on the stern, but that is for another purpose altogether. I have never heard of using a cork on the pipe at the bow. But that could just be me. As for your sink drain hose, the hose should end at a thru-hull seacock. You should be able to just close the seacock, and then disconnect and work on the hose. If there is no seacock, then I would start to worry. I can't imagine a production boat without using a seacock. If the seacock is not easy to turn, or won't turn at all, then be very gentle. It could've rusted or corroded shut, If you force it, you may end up braking parts of it off then you will have real trouble. If this is the case, then you should wait until you haul the boat to fix it.
Cork definitely is NOT a one-way valve! 
Is the pipe with the cork in it above the waterline or below the waterline? We need to know that before advising you whether it's safe to remove it. You also need find out what's on the inside of the hull--the other end of the pipe that has the cork in it--to provide some kind of clue as to why it HAS a cork in it. It shouldn't, btw...corks--except those in wine bottles--are not something normally found on ANY boat. As for your sink drain, I suspect JC nailed it...find the seacock that opens the drain thru-hull, open it--if you can--and I suspect your drain will drain. It would be a VERY good idea to find someone in your marina who knows something about sailboats to show you where everything is on your boat and how it works.
Is the pipe with the cork in it above the waterline or below the waterline? We need to know that before advising you whether it's safe to remove it. You also need find out what's on the inside of the hull--the other end of the pipe that has the cork in it--to provide some kind of clue as to why it HAS a cork in it. It shouldn't, btw...corks--except those in wine bottles--are not something normally found on ANY boat. As for your sink drain, I suspect JC nailed it...find the seacock that opens the drain thru-hull, open it--if you can--and I suspect your drain will drain. It would be a VERY good idea to find someone in your marina who knows something about sailboats to show you where everything is on your boat and how it works.
There are almost certainly no one way valves in your boat!! It appears that you have a through hull which is a threaded tube which penetrates through the hull to allow water to flow into and/or out of your boat. The through hull has a large head on the outside and, if it is not attached to a sea cock, has a large hex nut screwed onto the through hull on the inside of thehull. This thru hull may or may not have a valve called a sea cock on it to prevent water from flowing into the boat when you don't want it to. If you have an older Catalina you probably have "volcano" through hulls which are pipe stubs glassed into the hull. These are a cheap, dirty and unsafe solution and should be replaced immediately. You will probably also have gate valves which look like garden hose valves with round handles. These are also unsatisfactory. You should replace these with real through hulls and sea cocks. You will have to have the boat out of the water to do so. The best way to secure your through hull is to add a sea cock which is a valve, usually a ball valve, with a flat base. The through hull almost always has a straight (NPS) thread which allows it to be used on hulls of any thickness. A true sea cock has a straight thread (NPS) on the bottom to screw onto the through hull and a tapered pipe thread (NPT) on top to be used with pipe fittings. To accomodate the length of the through hull you will probably have to make mounting blocks to go between the hull and the sea cocks. Do not omit these as the valve is much more secure if supported by the mounting block instead of standing up on top of a long through hull. There is a raging controversy over whether or not to use reinforced plastic Marelon through hulls and sea cocks or to use bronze equipment instead. There have been reports of the handles on Marelon sea cocks breaking and of corrosion on bronze sea cocks. My own preference is for bronze but you can start a very long thread by asking everybody for their preferences and their reasons. There's a write up on installing through hulls and sea cocks in the archives which has a lot more detail on installing the right hardware. Some folks use bronze ball valves on their through hulls instead of sea cocks. This is a mistake as most ball valves have tapered (NPT) threads on both ends and don't provide a solid connection to the through hull. The difference in cost between a bronze ball valve and a bronze sea cock of the same size is trivial compared to the increased security for you boat. There shouldn't be a "cork" in any of your hull penetrations!! Seal it up with a valve or a threaded cap immediately even if it is a bad valve like a gate valve. This is dangerous and could fail and sink your boat. If your sink drain isn't working you can disconnect it if there is a sea cock and it is closed. You may have a connection between your sink drain and your ice box drain with a valve on one or both. If the valve is on the sink drain (it should be on the ice box drain) it should be open in order to allow the sink to drain. Do not confuse this valve with the sea cock which must be closed in order to remove the hose. The valve si usually on the ice box side as the bottom of the ice box may be below the water line when the boat is on that tack and sea water will flow up into the ice box, contaminate your food with salt and melt the ice. If the clog is in the sea cock or through hull there is a nifty way to clear it. Close the sea cock and remove the hose (now you can make sure the hose is clear) then put a long length of hose on the sea cock which will reach above the water line. Now, holding the top of the long hose above the water line, open the valve and use a long stick or something else skinny and stiff to clear the through hull. Close the valvsea cock, remove the long hose and replace the hose from the sink. All done.
- Status