Thru hulls and sea cocks

[rmbrown]

I know this question has been discussed at length but I couldn't really find anu common consensus...

I found a couple of leaky under water thru hulls and decided to replace all.  They are flush, except for the galley raw water intake, all marelon, and include a conglomeration of sea cocks and ball valves, some marelon, some bronze or brass... Not sure how to tell... But all standing very high of the hull.

I went to catalina direct and saw the one piece marelon valve and thru hull and liked what I saw, then read some scary stuff here.

What's the current common wisdom?

[Jon W]

My boat had ball valves on all thru hulls. I changed all thru hulls to Marelon flanged seacocks with backing plates. I chose Marelon instead of bronze because no grounding required, good test results, and an old friend of mine told me that sometimes bronze is overtightened and can damage the fiberglass.

By scary stuff on this website do you mean the guy who took the handle off and water flooded into his boat?

[Fred Koehlmann]

Our MKII from 2002 has all Marlon thru-hull valves (http://www.forespar.com/OEM-Valves.shtml). Don't know their life expectancy, but these all appear to be original. So at least 15 years so far. We haven't had an issue with any of them other than sometimes they have stuck. Never a leak. I hear that I should be using a specific lubricant on them before I launch the boat to ensure a smooth motion. If anything I have found that its been more difficult for me to know sometimes which way to turn the lever when i want to close it? I must be mildly dyslexic when trying to close them. 

[MarcZ]

Mine appear to be original as well, that makes them 23 ....

I must be mildly dyslexic when trying to close them. 

You are not alone in my short experience with forespar I had same issue - On the other hand trudesign handle is not symmetric and easy to identify turn direction

I have already made a decision on replacing seacocks  ,  still unsure about thruhulls. Can't find any information on how these age to push me over the edge.

Some say "When in doubt , rip it out" 

[Fred Koehlmann]

Are yours leaking? Other than being 23 years old, is there an issue with them? The saying that I like is: "If its not broken, leave it alone."

If you are concerned about an unexpected break, you should always have a plug or two on board, that fit your thru-hulls. i keep a "TruPlug" in our cockpit lock at all times, and hope to never use it.

[MarcZ]

- no leaks
- no clear issues other then age / unknown deterioration of the material

"If its not broken, leave it alone."

point taken

I have always kept a set of wood plugs on my boats -   your  "TruPlug" suggestion looks superior. I'm definitely getting these on board.

[rmbrown]

Jon W. - Yep... the handling falling off or breaking off, although it sounds like they can break off without flooding the boat?

MarcZ - I'd suggest we pool our data if I had any to offer.  I have to do something, though, 'cause I removed all mine last weekend. :O

Fred - I'm leaning toward going back with the marelon ones from Catalina Direct on the assumption that they can't be sinking boats left and right or surely they wouldn't still be selling them, right?!

[rmbrown]

For what it's worth, of the 5 size/configuration combos they carry, they have 1 or 2 of three of them in stock but they are typically special order and take 1-2 weeks.

I have all mine in my car, so I'll take inventory tonight and see where I stand.

[rmbrown]

Marc, I love the look of that Truedesign but I think you are right... that wouldn't work with our flush mount.  Filling and redrilling doesn't sound like any fun.

[MarcZ]

I'm planning to use trudesign seacock with existing or new forespar thruhull to avoid any modification of the hull
I already have one dry fitted and it looked and felt solid.
Will report more once it stops snowing and temp gets north of 32 

[rmbrown]

If you've got any pictures of those together, I'd love to see it.  Sounds like a promising combo.

[Jon W]

My apologies if this is obvious to everyone, but before dismissing Marelon it might be worth clarifying definitions -

"Sea cock is the term for a type of valve used to control intake or discharge of water through the hull. It is operated by a lever type handle usually operating through a 90° arc, giving a clear indication of whether it is open or shut, and is typically of the two following types:

Flanged Sea Valve – A Seacock with an integral flange used to individually and securely mount the device directly to the boat hull structure.

In Line Ball Valve – A Seacock designed to be supported entirely by the through-hull fitting"

I had all "In Line Ball Valve" types (see example 1st photo) when I bought the boat. I'd guess most of you do as well. I changed to all "Flanged Sea Valve" types with backing plates (see example 2nd photo) shortly after buying the boat. Lower profile and much more robust since the valve attaches at the hull. I would not use an "In Line Ball Valve" type regardless of composite or bronze if I can avoid it.

Marelon has both types available. I believe Catalina Direct only sells the "In Line Ball Valve" type.

[rmbrown]

Paralysis by analysis... maybe I'll just sit this season out and sail next year!

[Noah]

Another thing to consider is the type of tailpiece that connects to the valves and seacock and that it is the "correct" material, Marrlon-type material, not nylon, brass or PVC and that it has enough length to be DOUBLE CLAMPED, as is required for hoses under the waterline.

I am going through this exercise myself right now, as my boat has some PVC Tee fittings and some single clamped hose barbs. Trying to "clean-up" that stituation is a PIA as well as the knees. All very tight under the cabinetry in head and galley sink. I currently have OEM Marelon thru-hulls and vavles that work fine but plan to go the route Jon went with flanged seacocks, replacing my existing old flush mount Marelon thru-hulls (same as I have now) but replace the seacocks with flange mounted ones with backing plates. I like the added strength of the flange. Will do at next hullout in Oct.

[MarcZ]

John W - CD does sells both types
When you were installing backing plates was your hull relatively flat or did you have to deal with a bump like I have  ?