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  1. #1
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    Default Tonval skin fitting compatibility

    Hi
    wanting to set up a couple of small bilge pumps with associated pipe, ball valve, skin fittings and pipe tangs. I have sorted out the sizing of this via previous post on this. As the skin fittings will be about 2 feet above the waterline I am only looking at cheap fittings. Some I have been looking at are Tonval but there is a note to say that they should not be used in conjunction with ball valves or strainers. Is this just a particularly responsible retailer reminding buyers about the potential for losing your boat if the skin fitting fails or is there some other issue relating to fiting ball valves to these skin fittings?
    thanks as always.

  2. #2
    Keith 66 is online now Registered User
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    Tonval has been discussed on here before, do a search. Its just another 60-40 brass with a few other trace elements in, not suitable for underwater use as it dezincifies.
    Anyone telling you itrs bronze or gunmetal is telling porkies.

  3. #3
    PaulGooch's Avatar
    PaulGooch is offline Registered User
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    At two feet above the waterline, why not use plastic ?

  4. #4
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    Quote Originally Posted by PaulGooch View Post
    At two feet above the waterline, why not use plastic ?
    I saw a boat almost sunk after it sheared off a plastic through hull fitting coming in against a pontoon- the hull just caught the corner berthing, just a gentle nudge and the boat started going down moored to the pontoon. It has put me off plastic fittings since.

  5. #5
    PaulGooch's Avatar
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    Quote Originally Posted by catalac08 View Post
    I saw a boat almost sunk after it sheared off a plastic through hull fitting coming in against a pontoon- the hull just caught the corner berthing, just a gentle nudge and the boat started going down moored to the pontoon. It has put me off plastic fittings since.
    Obviously your choice, but i still cant see how the fitting, failed, broken or otherwise can sink the boat, if it is 2 feet above the water line.

    Am i missing something ?

  6. #6
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    Quote Originally Posted by PaulGooch View Post
    Obviously your choice, but i still cant see how the fitting, failed, broken or otherwise can sink the boat, if it is 2 feet above the water line.

    Am i missing something ?
    No you are not missing something. It's quite common to get thread drift on these forums due to people not reading the original question properly. There is no reason why Tonval or plastic skin fittings should not be used 2 feet above the waterline. There is also no reason why ball valves or anything else should not be attached directly to them either. Tonval should however never be used below the waterline and Aquafax and others should be shot for producing and/or selling scoop type fittings that are expressly designed for use below. Tonval is a 60/40 brass with additives to make it easy to cast/forge/machine. It is not bronze and should not be confused with bronze.

  7. #7
    vyv_cox's Avatar
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    I can think of no mechanical reason why a ball valve should not be fitted, so presumably they are guarding against galvanic corrosion. Fitted above the waterline I see no problem. I have the same arrangement on my little boat.
    Answers to some technical queries at http://coxengineering.sharepoint.com

  8. #8
    VicS is offline Registered User
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    Quote Originally Posted by catalac08 View Post
    Hi
    wanting to set up a couple of small bilge pumps with associated pipe, ball valve, skin fittings and pipe tangs. I have sorted out the sizing of this via previous post on this. As the skin fittings will be about 2 feet above the waterline I am only looking at cheap fittings. Some I have been looking at are Tonval but there is a note to say that they should not be used in conjunction with ball valves or strainers. Is this just a particularly responsible retailer reminding buyers about the potential for losing your boat if the skin fitting fails or is there some other issue relating to fiting ball valves to these skin fittings?
    thanks as always.
    I'd have thought that the composition of other fittings would be more important than what they physically are.

  9. #9
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    Thanks for responses, pleased to see some confirming my feeling that the sellers (Aquafax) are just being refreshingly diligent in reminding people about the dangers inherent in skin fittings corrosion and subsequent failure.

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