Replacing thru hul gate valves

J

Jdaniel343

.
Dec 7, 2014
78
Catalina 27 Alcova Boat Club
I plan on replacing all original gate valves on my 1977 Catalina 27. What are your thoughts on replacing the thru hulls. These seem to be molded in. Should I replace.
There are no problems with any of this now but I would like to be able to shut flow off with a swing of a handle.
Can I replace these gate valves with hardware store type bronze ball valve?
I sail on a lake in Wyoming, only from May thru September.
Thanks
 
The Garbone

The Garbone

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Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
Buy real thru hulls from someplace like Defender. Type 83 or some such. Should be under $100 per.

On my C30 I recently replaced one of the glassed in nipples, just drilled out the old from the outside with a hole saw and put the new in with a nice sealant.
 
J

Jdaniel343

.
Dec 7, 2014
78
Catalina 27 Alcova Boat Club
Garbone, did you replace with bronze or Marlon? I am thinking of Marlon due to the fact they are made of inert material and should never corrode.
If I go with the Marlon, what is wrong with using brass ball valves?
If I went with bronze thru hull I would also use a bronze ball valve.
 
hvbaker

hvbaker

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Oct 5, 2010
322
Catalina 30 mkII St. Augustine
Jdaniel343 said:
Garbone, did you replace with bronze or Marlon? I am thinking of Marlon due to the fact they are made of inert material and should never corrode. If I go with the Marlon, what is wrong with using brass ball valves? If I went with bronze thru hull I would also use a bronze ball valve.
Click to expand
You should never use brass in any place that galvanic corrosion can occur. Brass is an alloy with zinc!!! Need I say more?
 
centerline

centerline

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Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
bronze is good, but there is no real reason to use a bronze ball valve just because you have a bronze thru hull.
you can use either bronze on marelon or marelon on bronze, or use either product on itself, OR the existing fiberglass nipple.. it dont really matter as long as you dont over tighten them, which is a bad practice.

marelon is a good product, but some say the handles are a bit weak... but in truth, its not so much the handle being weak as it is a lack of maintenance on the valves, so they can be stiff to turn, possibly breaking the handle.
im very familier with the product, and use a lot of marelon fittings myself and ive never seen it happen, but then I dont work on hundreds of boats a year either.

with a bronze valve, you can turn pretty hard on it without damage, but again, you shouldnt have to turn that hard.

brass is bad... it is composed of zinc alloyed with copper, so the zinc will disintegrate over time and leave the apparently fine looking brass fitting nothing but a weak sintered piece of rotten/corroded copper.... as soon as it is bumped or pulled on, it will break off leaving you with a hole in your boat. dont use brass...
 
The Garbone

The Garbone

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Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
I used Marlon thruhull and valve. Corrosions being the thing to avoid.
 
philwsailz

philwsailz

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Dec 11, 2008
1,338
catalina C27 stillwater
Short, sweet, Stock thru hulls are nipples glassed in through the hull. Bad bad bad.

Gently remove the factory nipples. Grind inner hull smooth. Bed in new flanged seacocks with backer plates and proper thru-hulls.

That is a grossly over- simplified description, as there are tons of posts on the topic, as well as several how-to threads.

DO NOT leave the stock stuff in place.

Glub Glub Glub...
 
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