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Discussion Starter #1
So I need to change the Thru hulls in my boat what is the best material and best thru hulls ? Plastic, steel ,bronze?

:2 boat::2 boat:
 

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Nothing wrong with good quality bronze stuff. Check out the advice on Maine Sail's great site.

You used the word "plastic" but there are none (or should be none) made solely out of plastic.

Equivalent to bronze in strength are the composite ones from Forespar, and you want the one-piece "93 series" valves. Strong and never any concern about electrolysis.

If you go with bronze, go with a name brand, to be sure of getting a true marine alloy.
 

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A good quality bronze thruhull with a real bronze seacock (not a ball valve), from a reputable manufacturer like Groco or Perko would be my choice. Also keep in mind that if you have a cored hull, you must make sure that there is no core where the thruhull goes through the hull. If necessary, dig out the core around the hole and fill that space with epoxy putty so when you tighten the thruhull, you are doing it against a hard surface, not the soft care material of the hull.
 
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Composite(plastic) thru hulls will not corrode, but I understand they do degrade over time. Some brands are similar in breaking strength to bronze, others aren't. I can't keep them straight.

Quality bronze thru-hulls and valves (Groco, Perko), when properly installed, will outlast the owner. Note: crappy chrome coated ball valves, often OEM on some production boats, are not the same. I'm slowly changing all mine out.

Steel is silly.

That's my story and I'm sticking to it. :)
 

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Are you sure you need to change all of the thru hulls? Would be curious to hear what problems you're having that require changing them out.......
 

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Discussion Starter #10
Are you sure you need to change all of the thru hulls? Would be curious to hear what problems you're having that require changing them out.......
They are plastic so I was told that plastic is no good and I need to change them.

The person that told me that has like 30 years in the business of boat repair.

So I guess thats my only reason they are not having any issues...

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A good quality bronze thruhull with a real bronze seacock (not a ball valve), from a reputable manufacturer like Groco or Perko would be my choice.
In the US there is only one "tapered cone" seacock brand left in existence and that is Spartan Bronze ... Neither Groco, nor Perko, nor Apollo/Conbraco etc. make tapered cone seacocks any more. All except Spartan now use ball valves... However be ready for a shocker when ordering Spartan $$$$$$$$.....
 

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Discussion Starter #14
In the US there is only one "tapered cone" seacock brand left in existence and that is Spartan Bronze ... Neither Groco, nor Perko, nor Apollo/Conbraco etc. make tapered cone seacocks any more. All except Spartan now use ball valves... However be ready for a shocker when ordering Spartan $$$$$$$$.....
I looked them up and you are not kidding crazy expensive!!

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I suppose it is about the type of boat, and the type of sailing you plan to do, but no matter what the "specs" are on non bronze thruhulls and seacocks, I doubt I'd be at all comfortable with any of them, if I was on a boat in a norther in the Stream, dropping 20 feet or more off a wave into a hole that those conditions can create.
Just like with my ground tackle, I'd rather pay the price for peace of mind, than worry about something that I shouldn't need to worry about in conditions when there's plenty else to worry about.
 
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I suppose it is about the type of boat, and the type of sailing you plan to do, but no matter what the "specs" are on non bronze thruhulls and seacocks, I doubt I'd be at all comfortable with any of them, if I was on a boat in a norther in the Stream, dropping 20 feet or more off a wave into a hole that those conditions can create.
Just like with my ground tackle, I'd rather pay the price for peace of mind, than worry about something that I shouldn't need to worry about in conditions when there's plenty else to worry about.
Yes, but what about all those 'CE" rated boats with non standard (IMHO) fittings..ha ha
 

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On my previous boat, I installed a Marelon seacock by Forespar. Marelon is a glass reinforced plastic sold as "suitable for below the waterline applications."

Marelon by itself, is not the problem. The design of Forespar's seacocks is the problem. The handle is held on by nothing more than a single, small screw. These valves have been known to fail in a mode where the screw and handle shear off, allowing water to enter the boat via the handle attachment point and there is no way to rotate the ball to shut off the water. Most (if not all) of the bronze ball valves have a stem that you can rotate with a pair of pliers or channel locks to shut the valve, if the handle were to shear off.

I believe MaineSail's website explains this, and he also indicates the only Forespar model that doesn't suffer from this problem. I have no problem trusting modern materials, but the design is poor so I won't use that particular model again and would probably select a bronze valve until the designs improve.

While I understand your reaction is to respect the guy with 30 years' experience, sometimes that experience also leads to unnecessary prejudices. I wouldn't race to replace all of my valves just because they are "plastic." More investigation is warranted here.

- What kind of plastic?
- What is the design/model and manufacturer of the valve?
- Are they all below the waterline?
- What is the application?
- What condition are they currently in?

Maybe none of these valves need to be replaced right away. Maybe you only need to replace a couple of the most critical ones.
 

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Yes, but what about all those 'CE" rated boats with non standard (IMHO) fittings..ha ha
I put about as much faith in those ratings as I do in all the anchor tests. At 3AM, when the wind is onshore at 40 to 60 knots, and the seas are breaking over my bow, I think conditions far exceed any testing, especially by invested interest parties.
Who you gonna trust? Your own gut, that's who. And probably MaineSail.
 

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While I understand your reaction is to respect the guy with 30 years' experience, sometimes that experience also leads to unnecessary prejudices.
I know quite a few guys in the business that claim 30 years experience. What many really have is one years experience repeated 30 times :)
 
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