I have just purchased a 81 cat 27 and during the survey I have been advised to change out the gate valves with ball valves. They donot leak and they are working just great. My question is? what size is the thru hull threaded shaft so that I can purchase the corect size valve. as I want to change them in the water if at all possible and save the haul out fee. Any and all suggestions will be appreciated.I had the bottom inspected by a diver and it is in great shape as the bottom was just done with no blisters and no cat smile. Thanks for your help. "MIC"
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Garry @ S/V TASHTEGO
Not only are the gate valves not suitable but the "volcano" mounts that Catalina made are also unsafe. You should replace them with proper thru hulls and sea cocks. Don't just replace the gate valves with bronze ball valves, do the job right and sleep easy. For a longer description of the process see the following in the archives for 2001. Thru Hulls Submitted by Garry @ S/V TASHTEGO on 07/13/2001 at 11:39AM regarding Catalina 27
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Mic
Ok, you guys were correct I started to look for a "cheap" way to change out the gate valves. and as I started to change one I found two good ones and one that was real loose and starting to leak. Needless to say it was a mad dash to Dana Point's Boat yard so now instead of a "Cheap" way, I am going to pay the piper and have all the thru hulls changed and new ball valves installed. (don't be saying) "I told you so". But I bet I will sleep a little easier. Thanks for the advice. "MIC"
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Garry@S/V TASHTEGO
No Ball Valves
In case you haven't read my old post yet I will re-issue my warning. DON'T PUT BRONZE BALL VALVES ON YOUR THRU HULLS!! Almost all ball valves have tapered pipe (NPT) threads. All thRu hulls have straight pipe (NPS) threads so that they can be used on hulls of any thickness. This means that when you screw a tapered thread ball valve onto a straight thread thru hull only a couple of threads will be engaged. I'm told that there are, in fact, some straight thread ball valves out there. Even so, don't use them. A sea cock has a broad base which should be screwed down on a solid backing block. True sea cocks have a straight thread on the bottom to screw onto the thru hull and a tapered thread on top to take pipe thread accessories. The result is that they can be screwed all the way on, with many threads engaged. The broad base prevents breaking the thru hull if knocked hard. Through bolting the sea cock flange through the hull will hold the sea cock in place even if the thru hull fails. The difference in cost is about $20 per - but consider what you paid for the boat and what you'd pay if it sank!
In case you haven't read my old post yet I will re-issue my warning. DON'T PUT BRONZE BALL VALVES ON YOUR THRU HULLS!! Almost all ball valves have tapered pipe (NPT) threads. All thRu hulls have straight pipe (NPS) threads so that they can be used on hulls of any thickness. This means that when you screw a tapered thread ball valve onto a straight thread thru hull only a couple of threads will be engaged. I'm told that there are, in fact, some straight thread ball valves out there. Even so, don't use them. A sea cock has a broad base which should be screwed down on a solid backing block. True sea cocks have a straight thread on the bottom to screw onto the thru hull and a tapered thread on top to take pipe thread accessories. The result is that they can be screwed all the way on, with many threads engaged. The broad base prevents breaking the thru hull if knocked hard. Through bolting the sea cock flange through the hull will hold the sea cock in place even if the thru hull fails. The difference in cost is about $20 per - but consider what you paid for the boat and what you'd pay if it sank!
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Mic
Ball valves
Thanks Gary for your concern on the thread differences. I just got off the phone with the yard Mgr.and he assured me that the "marine" ball valves and thru hulls of today are matched so the thread problem does not exist in the new style. Thanks for your input and your safty concerns that is why I deceided to change all the original "thru hulls" with the "ball valve type" sea cocks. Thanks again "MIC" PS I may need a co-signer if you are avaliable.
Thanks Gary for your concern on the thread differences. I just got off the phone with the yard Mgr.and he assured me that the "marine" ball valves and thru hulls of today are matched so the thread problem does not exist in the new style. Thanks for your input and your safty concerns that is why I deceided to change all the original "thru hulls" with the "ball valve type" sea cocks. Thanks again "MIC" PS I may need a co-signer if you are avaliable.
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Mic
Sea cocks aka Ball valves
Hey Gary: The error was mine. They are thru-Hulls with "sea cocks" which are Ball type valves.Its kinda like Charts vs Maps they all mean the same to some of us wanta-be "die hard" sailors. Even though I mis-spoke thanks again for your help. "MIC"
Hey Gary: The error was mine. They are thru-Hulls with "sea cocks" which are Ball type valves.Its kinda like Charts vs Maps they all mean the same to some of us wanta-be "die hard" sailors. Even though I mis-spoke thanks again for your help. "MIC"
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