I replaced all marelon thru hulls 13 years ago with bronze thru hulls. Just one failed thru hull will sink your boat within minutes.
Bob McPeek, Pau Hana, NS30C
I guess this would bring up the discussion of which is better, Marelon or bronze. When I bought my boat it was equipped with all Marelon thru hulls and valves. I thought this was a good thing. Is there a deep dark secret out there about Marelon that should make me think about switching to bronze?
Jamie Morrison
Dexterity II
30U 225
Halifax, Nova Scotia
I would stick with Marelon because it is not subject to electrolysis but they do need maintenance. I personally think that there are way too many thru hulls on nonsuch boats. I have been contemplating removing some, like cockpit drains and sink drains. Run all to stern.
I’ve had Marelon valves in boats for more than 25 years and I absolutely do not believe they will break, other than perhaps the handle. You could beat on one with a hammer and not break it. Other than the word “plastic” striking fear in some hearts, I don’t understand where this concern for the strength of Marelon comes from.
Paul Ring
NS260 #3, “Polecat”
Fairhope (AL) Yacht Club
— On Mon, 6/14/10, Jamie Morrison jamie.morrison@NS.SYMPATICO.CA wrote:
> From: Jamie Morrison jamie.morrison@NS.SYMPATICO.CA
> Subject: Re: Replacing Marelon valve
> To: NONSUCH-L@LISTSERV.AOL.COM
> Date: Monday, June 14, 2010, 2:35 PM
>
> I guess this would bring up the discussion of which is better, Marelon or bronze. When I bought my boat it was equipped with all Marelon thru hulls and valves. I thought this was a good thing. Is there a deep dark secret out there about Marelon that should make me think about switching to bronze?
>
> Jamie Morrison
> Dexterity II
>
> 30U 225
>
> Halifax, Nova Scotia
|
Marelon seacocks meet USCG and ABYC requirements for thru hulls, which are fairly rigorous: they must withstand a 500 pound load applied the worst direction to the end of the tailpipe. However Hinterhoeller did not use Marelon seacocks, they used Marelon thru hulls with a Marelon valve screwed onto them. This is not (and as far as I know was never) a USCG or ABYC approved arrangement. The seacocks have a large flange at the base and secure to the hull with three bolts independently of the thru hull fitting. The Marelon flanged seacocks still meet the requirements, even though Forespar no longer files the necessary paperwork for official approval.
I replaced all the thru hulls and valves on mine with like, because the older valves were getting hard to turn and have a weaker stem than the newer ones. I clamped one of the old ones in a fixture and broke it off with a hammer to see how hard it was. It took a reasonable wallop, but less than a bronze one of similar size. On the other hand a corroded “bronze” one will crumble in your hand. I say “bronze” because it is nearly impossible to tell what the fitting you are buying is made from, short of sending it to a lab. Many have a high percentage of zinc, which I would call brass.
In my mind the best fix would be to remove the thru hulls and replace them with a proper Marelon seacock. These don’t corrode, are quite strong, and if you smear a little teflon grease on them once a year before launch (can be done with a Q-tip from the outside without disassembly) will last nearly forever.
On the other hand, I haven’t heard of a single Nonsuch sinking due to the failure of the original installation, so it is probably much ado about nothing.
Jon Fitch
‘Anomaly’
Hi All, launched 2 Saturdays ago 8:00 AM, brought boat to our club’s dock, discovered a small leak, worked on it for 1.5 hours, reduced to trickle before calling my mechanic, he worked on it for a hour and could not reduced it further and advised me not to put her on her mooring (and probably spend the night on board), plug battery charger to shore power to keep the bilge pump float switch operational. Diagnosed problem as possible cracked Marelon thru hull. He could haul us out Monday if I got the parts, recommended Bronze. After rigging the boat checked on leak, now 10 times worse and auto float switch not working (Murphy’s Law). Someone suggested diving on it and forcing a wood plug in opening. Instead I called the new Marina in town for an emergency travel lift haul out, finally out by 6:00 PM… The Marelon did not fail, instead was spinning in the opening and may have loosened when the attached hose was replaced over the winter. Boat back in water Tuesday, cost of this adventure, around $1000. Considering replacing all thru hulls with bronze over the coming year. BTW, even if you wanted to you cannot drive a plug into the opening, opening is covered with a grate, at least it is on my boat.
Bob U, Wharf Rat, NS 30, #203, 1983
When I am working on my boat I find “opening” old parts and repairing fixtures often causes more failures. Paint is a wonderful sealant as is time undisturbed.
I think I’d be biased to Marlon if only for the fact the corrosion is less of an issue. I guess in a fire they could be less sturdy than bronze but then I’d maybe have other more pressing issues 
Got to believe George Hinterhoeller thought long and hard about using Marelon valves on his boats.
Is that a Marelon failure or the failure of its original installer to properly cement/seal the interior tightening nut to the Marelon thro-hull? Wouldn’t the same thing potentially happen to an uncemented bronze thro-hull?
Chris Inniss
30U 324 Peace on Earth
Chicago
What expenses did the $1000 cover? That seems like a lot.
FYI Haul and launch $512, labor $315, balance is parts and taxes. Bob U, Wharf Rat, NSC #203 Scituate, MA
That price, One Boat Unit, is not bad. When I broke one through hull, I had the boat hauled and replaced all but the engine and watermaker through hulls at the same time.
Phil LeVIne,MeSays