Marelon Seacock Replacement

[Seahunter]

Marelon sucks. Ask the yard to price you a lift to switch the fitting (leaves you on the lift). If you have everything ready and use Sika (fast dry) you can splash in 2-3 hours.Split the marelon with a chisel and smash the rest away; have the new fitting/valve ready with wrenches etc., (Make sure you're not hunting for something you need). Install the hose(s) after the boat splashes.

[CarlF]

My experience is that Defender is very good with special orders as long as they carry anything from the manufacturer. Just call them. Still good pricing. It can take a while for the part to come in.

Installation instructions

http://www.forespar.com/pdf/93Series...stallation.pdf

Carl

[Rustic Charm]

Hi everyone, pardon me for bringing this up again, but I'm hoping that as it is the mid of 2013, things may have changed, valves may have modernized a little more etc.

I've just pulled my boat out and need to replace the 1 1/2 inch nylon seacock, for the head. The stainless pin holding the ball valve rusted away and it was stuck in the open position.

My boat is steel. It's got a welded pipe on the inside of the hull for a through fitting.

My question is, should I replace the seacock with stainless or have the nylon ones become good enough to use now days. The stainless ones seem smaller, but I'm worried about the dis-similar metals problem. My engine seacock was stainless when I purchased the boat and it fell apart in my hand when I turned it to see how tight it was.

[Watercolor]

tedsherrin -

Don't know if this will help, I molded some plumbing parts out of a material called RTPU Rigid thermoplastic polyurethane. I made them in only the 1.5" size and one of the fittings was a nipple fitting. I've always thought that they might work well on aluminum and steel boats as an isolator to be used with a bronze or SS seacock. They're NPT threaded and you'd need an NPT threaded coupler. But they would isolate the metals.

I don't make them anymore, but if you want I'd be happy to send you one or two, they're free, but you'd have to pay shipping.

The material meets all the ABYC approval requirements. Attached is a PDF showing how they compare to other plastics regarding impact. For comparison a 1.5" bronze fitting will last around 6 to 8 hits.

[Watercolor]

Tedsherrin -

I have one other shipping option if you want to try one of the nipple fittings. My sister lives in Sidney and will be here in Vermont, USA for holiday. I might be able to convince her to bring one or two back to OZ. But that would take some time.

[s/v Jedi]

Originally Posted by tedsherrin

Hi everyone, pardon me for bringing this up again, but I'm hoping that as it is the mid of 2013, things may have changed, valves may have modernized a little more etc.

I've just pulled my boat out and need to replace the 1 1/2 inch nylon seacock, for the head. The stainless pin holding the ball valve rusted away and it was stuck in the open position.

My boat is steel. It's got a welded pipe on the inside of the hull for a through fitting.

My question is, should I replace the seacock with stainless or have the nylon ones become good enough to use now days. The stainless ones seem smaller, but I'm worried about the dis-similar metals problem. My engine seacock was stainless when I purchased the boat and it fell apart in my hand when I turned it to see how tight it was.

Stainless steel is the ticket. Contact with the steel hull and stand pipe should not be a problem at all. I suggest you select a quality valve like this one from Groco:


The flanged adapter that is discussed here on CF a lot is also available in stainless steel, as are the thru-hull fittings. I think your standpipe is better as long as it has some supports.

[Rustic Charm]

Thanks Watercolour, that's very generous of you. I don't need to add anything else to it though and I think to do so I'd simply be adding something else that gives an opportunity to go wrong. I think I'll take a picture of my through fitting and it will indicate what i've got. Jedi, thanks for the picture. I can certainly put in place a very good quality marine suitable stainless steel valve just like the one you have shown. It's $189, which I don't mind paying for piece of mind. It will stick out a lot more, but if it makes it secure then I can work around that. . . just out of curiosity with the pdf you put their 'watercolour', why is the testing done with hitting it with a sledge hammer? I mean, would a fitting in a boat every get hit with such sudden preasure like being hit with a sledge hammer?

[Watercolor]

Tedsherrin - no problem. I'm not a metals expert, so know little about how SS would work with regular steel in salt water. I know the impact capability of this material and thought it might make a good isolator for the different metals.

To answer your questions:

Why is the testing done with hitting it with a sledge hammer?

I live in Vermont where a spitting maul like the one in the pictures is common. Most mauls are between 6 to 8 lbs with a 30" handle. So it was easy and convenient to use for a pendulum to produce consistent hits.

I mean, would a fitting in a boat ever get hit with such sudden preasure like being hit with a sledge hammer?

The answer is YES. Mainesail's testing of seacocks and thru-hulls was initiated because a, he thought, well secured spare alternator broke out of its enclosed space and nearly destroyed a bronze thru-hull/ball valve seacock during a storm. An alternator weighs about 15 lbs or more. One incident I think is fitting seems the least likely to happen. A boater in Florida was getting his boat ready. It was on a face dock just off the inter-coastal. He unloaded his car and put a 20 lb anchor in a cockpit locker. He went home to get some more stuff and when he came back the boat under water. It appeared that someone had waked his boat and the anchor nailed the plastic seacock sheared it right off and the boat sank. A six lb pipe wrench or crescent wrench, etc. dropped from 4 feet into a bilge would have clearly compromised most of those plastic fittings. I can provide may more stories like that. Also, you should remember that this impact is equally possible on the outside of the hull.

We hit a submerged pole with a metal piece attached. The metal put a groove a good 1/4" on the underside of the hull, below the waterline. That's impact. If it hit a bronze thru-hull I believe the thru-hull would have bee mangled, but still functional. A plastic thru-hull would simply be history.

You'll find that loose dunnage is mentioned by most boat experts as a major concern with regard to boat safety. Actually, I feel that the sledgehammer test is actually an under representation of the real impact a thru-hull can receive.

Here's a video by Yachting Monthly about how to deal with the after effects of something like a thru-hull being impacted either internally or externally.

Yachting Monthly's Crash Test Boat - Through Hull Failure - YouTube

Hope this is of some help.

[Boracay]

I've fitted TruDesign valves into Boracay. New Zealand firm sez they're survey rated.

I've only used the smaller ones (1") but so far no worries.

I experienced corrosion from a SS through hull that was extensive enough to cause a leak and an expensive repair.

[Rustic Charm]

Originally Posted by Boracay

I've fitted TruDesign valves into Boracay. New Zealand firm sez they're survey rated.

I've only used the smaller ones (1") but so far no worries.

I experienced corrosion from a SS through hull that was extensive enough to cause a leak and an expensive repair.

Hi there, I've tracked down the tasmanian supplier of these 'trudesign' valves. I can get a 1 1/2 inch valve for just $90. There web page has a number of certifications specifically for marine use. So I think I'm going to try these. It's not the cost that concerns me, it's the fact that a ss engine cock fell apart in my hands greatly concerned me. I'm keen to hear if anyone else has tried these ones.

I know some people are using Philmac brands, but to my knowledge they are not made for the marine industry but for irrigation.

[Wanderlust]

BIAS Boating has had these valves on special for $49.95 for some months. At least they look the same, and the wording from the website is identical. The versions from BIAS can be connected to an electronic monitoring system to show which ones are open or closed.

Monitored Ball Valves

I am no expert on these, but after reading on this forum about nylon fittings below the waterline I would choose bronze. But with a steel boat it seems your options are more limited.

[Rustic Charm]

Originally Posted by Wanderlust

BIAS Boating has had these valves on special for $49.95 for some months. At least they look the same, and the wording from the website is identical. The versions from BIAS can be connected to an electronic monitoring system to show which ones are open or closed.

Monitored Ball Valves

I am no expert on these, but after reading on this forum about nylon fittings below the waterline I would choose bronze. But with a steel boat it seems your options are more limited.

Yes, they are the same valve, just sold by another shop, but at virtually half the price. Thanks for this, I'll order them from here instead. The non monitored ones are only $30-$40.