Seacock Replacement: Grand Deer

[TayanaCruiser]

I just removed a Grand Deer seacock from a Tayana 37 (see attached picture). I am looking for a compatible replacement, any ideas?

[rbk]

When I did ours on our T37 I replaced all with groco flanged adapters and in-line valves like this:
https://www.groco.net/products/valve...flange-adaptor

They also have regular seacocks as well but the above install is easier and cheaper to repair should a valves fail.

[TayanaCruiser]

Thanks rbk. Did you end up using bronze or stainless? Also, did you bolt the flange adaptor to the backing plate or just use 5200?

[rbk]

Bronze. No through bolts, existing backing blocks and 5200. The cost for the flange adapters and in line valves was more than straight seacocks, but being able to throw any cheap hardware store valve on in a pinch and low cost and ease of replacement was what settled it for me.

[Orion Jim]

https://marinehowto.com/replacing-th...-and-seacocks/

https://marinehowto.com/seacock-backing-plates/

An alternative to quick and dirty.

[stormalong]

Compatibility just means that the through hull fitting properly fits the hole in the hull.

Bronze is one option, Plastic is another. Stainless steel is not a good choice for a through hull - sea cock combination. Stainless steel is susceptible to crevice corrosion.

Any metal can be effected by galvanic corrosion so the alloy used is very important. Only certain bronze alloys are suitable. There has been considerable discussion on this discussion board about the inadequacy of European (CE) standards for sea cocks resulting in the necessity to replace them in only a few years.

I prefer plastic components as they are immune to galvanic corrosion. There are two major makers of plastic sea cocks and fittings. Forespar and TruDesign. My 35 year old boat was built with Forespar Marelon fittings. I have replaced some through the years but many are original and working fine.

The original design of Forespar sea cocks does not meet today's standards for sea cocks. They now offer proper sea cocks that meet current standards. The plastic sea cocks are ball valves and only need lubrication to keep them working.

I have no TruDesign fillings but there are many positive reviews of them.

[GordMay]

Greetings and welcome aboard the CF, TayanaCruiser.

[skwanderer]

Originally Posted by stormalong

Compatibility just means that the through hull fitting properly fits the hole in the hull.

Bronze is one option, Plastic is another. Stainless steel is not a good choice for a through hull - sea cock combination. Stainless steel is susceptible to crevice corrosion.

Any metal can be effected by galvanic corrosion so the alloy used is very important. Only certain bronze alloys are suitable. There has been considerable discussion on this discussion board about the inadequacy of European (CE) standards for sea cocks resulting in the necessity to replace them in only a few years.

I prefer plastic components as they are immune to galvanic corrosion. There are two major makers of plastic sea cocks and fittings. Forespar and TruDesign. My 35 year old boat was built with Forespar Marelon fittings. I have replaced some through the years but many are original and working fine.

The original design of Forespar sea cocks does not meet today's standards for sea cocks. They now offer proper sea cocks that meet current standards. The plastic sea cocks are ball valves and only need lubrication to keep them working.

I have no TruDesign fillings but there are many positive reviews of them.

Interesting. I had marlon thru-hull and valves (Forespar) and just replaced all with the groco bronze fittings. The boatyard suggested "all bronze below waterline, plastic above it" and makes sense to me. I had a handle snap off in my hand when closing the marlon valve of my raw water intake; not a good feeling. Curious about other folk's POV on the matter.

[sengland]

Originally Posted by TayanaCruiser

I just removed a Grand Deer seacock from a Tayana 37 (see attached picture). I am looking for a compatible replacement, any ideas?

I was concerned about the flange size to fiberglass thickness so added my own flange to give it strength.

[Clivevon]

Recommend TruDesign as 1st option. Worth a good look , no corrosion, no maintenance, they just keep on working. I have 10 on my boat, fitted 7 years ago, no problems at all. OK, rave over…

[PhilC]

Here in NZ the standard recommendation is Trudesign using the collar on through hull.

[Clivevon]

For example: my cockpit drains need to be open, whether the boat is in or out of the water. So every year or two i think i really ought to close & open them, dont want them seizing up. So i do that. No resistance, no strain, no effort. They just work. An infant could do it. No worries. I like that.

[stormalong]

Originally Posted by skwanderer

Interesting. I had marlon thru-hull and valves (Forespar) and just replaced all with the groco bronze fittings. The boatyard suggested "all bronze below waterline, plastic above it" and makes sense to me. I had a handle snap off in my hand when closing the marlon valve of my raw water intake; not a good feeling. Curious about other folk's POV on the matter.

Forespar had a problem with handles breaking about 30 years ago. They were redesigned way back then. They also were not flanged sea cocks - they were just ball valves. Now they are available in both forms.

I see comments that say the handle broke off 20 years ago and I will never buy Forespar again. That is ancient history. I don't see commenters with failed bronze sea cocks say they will never buy bronze again. Why is that? With bronze you can never be sure that the alloy is correct. That is why I referred to the thread about the European (CE) rules that only require that sea cocks last five years. European builders can use cheap marine fittings and state that they meet CE regulations. You will still have to replace all underwater bronze fittings in five years.