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Old 21-08-2012, 07:48   #46
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Location: Eastern Ontario
Boat: Ta Chiao CT 35 Jack, CS27 Christina, Ranger 23 Strider, I14 Aggie
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Re: Seacocks, what material?

"If you are worried about lightning strikes and /or have bonded your seacocks, then the safest route for fiberglass boats is to remove them and replace with a marelon through hull with a marelon seacock."

Obviously, if you are using Marelon for the seacock and thru hull, you should not try to bond to them. Your ground is in order of preference, an exterior grounding plate, prop shaft, or keel.

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Old 21-08-2012, 08:49   #47
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Location: In Mexico, working on the boat
Boat: Hallberg Rassy 35. and 14ft.Whitehall pulling skiff.
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Re: Seacocks, what material?

Originally Posted by bobconnie View Post
Ive seen 5 yr old marelon so fragile from heat in the engine room they were installed in you Could break them with a small ball peen hammer !! I know I could have kicked it and done the same thing !! maybe on a Aluminum boat where they need to be used, ok but I don't own a aluminum boat so it is and will be Bronze for me !! just my 2 cents

Inconclusive. You did not kick it and you did not hit it with a hammer. It just "looked" bad.
My gripe with Marelon is they jam with time. Oh sure...'just exercise them every 6 months. Sorry...with most owners...out of sight, out of mind.
...oh...almost forgot...

"Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: Wow - what a ride!"
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Old 01-10-2012, 14:55   #48
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Re: Seacocks, what material?

Originally Posted by S/V Illusion View Post
Do any high end boat manufacturers use marelon valves?
My name is Chad Goodwin, I am a rep for Forespar in the SE and carribbean. Forespar is installing over 70% of the valves installed in power and sailboats in the US now. The '93' series valves have really taken off over the past 10 years.
Wally, Morris, Hylas, Tartan, Volvo 70's, Hinckley, Sabre, Swan, Baltic, Island Packet(just converted from Bronze), and Gunboats to name a few
If you have any questions please don't hesitate to ask. you can message me or email
I hope that helped.
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Old 02-10-2012, 12:14   #49
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Re: Seacocks - What Material ?

Hi. For the 93 series valves that get installed, do the installers typically drill through the base of the flange to add fasteners to the backing plates? Or are the valves held manually to the backing plate and hull? And are the backing plates typically made of fiberglass, or another material (marine plywood, maybe)? Any other instructions you want to add are welcome.
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Old 02-10-2012, 12:25   #50
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Re: Seacocks - What Material ?

You basically install a marelon valve the same way you stall a bronze valve except you don't need to ground it. I have copied and pasted the marelon installation guide sans pictures. If you want I could forward you the pdf if you send me an email. Hope this helps.

This marine seavalve is made of MARELON®, a glass reinforced nylon composite. It exceeds standards for
use set by the U.L. (Underwriters Laboratory) and the American Boat and Yacht Council (A.B.Y.C.). It is a
complete system including thru-hull fitting, valve body, and hose connector.
HULL OPENINGS: Prepare a clean round hole in the desired location and of the appropriate diameter
for the chosen thru-hull fitting per the requirements below. For flush head thru-hull fittings only, make an
external 45 deg. chamfer ¼” deep. If the recommended backing block is used, a uniform hole diameter
must extend through the backing block.
½” and ¾” Thru-hull/seavalves – 1-1/8” hole
1” and 1-1/4” Thru-hull/seavalves – 1-1/2” hole
1-1/2” and 2” Thru-hull/seavalves – 2-1/8” hole
BACKING BLOCKS: A backing block or an equivalent structure molded integrally into the resin/glass
hull lay-up is required for installations on all non-flat hull surfaces. This is also recommended procedure
for flat surfaces as well. For wood backing blocks, white oak is a commonly used wood. There may be
other suitable materials as well.
THRU-HULL FITTING LENGTH: The thru-hull fitting, when fully installed, should project beyond the
internal hull/backing block surface no less than ½” and no more than 1-1/4”. Engagement of five (5) full
threads will generate the full loading strength of the thru-hull/seavalve assembly, which is well in excess of
the 500 pounds, required by the U.L. and A.B.Y.C. standards.
BEDDING: The thru-hull fitting’s external flange should be properly bedded when the fitting is inserted
into the hull. The exposed male threads protruding from the inside of the hull should be applied with
bedding material as well. The surface of the female threaded round king-nut portion of the valve, which
interfaces with the internal hull surface, may well be bedded also, but it is not an absolute requirement and
the loading strength will not be impaired if it is not done. Bedding compounds such as 3M’s #5200, Sikaflex
or Boatlife are to be recommended as well as others that are equally suitable.
“93” SERIES THREAD FORM; The thread form used on these thru-hull fittings and king-nuts is
a non-tapered buttress type of thread design. This thread form has a higher load carrying capacity,
particularly for polymeric materials. Warning, a standard pipe threaded thru-hull fitting
will not fit with the king-nut on these valves. For a standard pipe threaded thru-hull fitting, use
our valves that have standard female pipe thread outlets instead of a king-nut base. A buttress
thread design with the same amount of clearance as for a conventional pipe thread will give the
impression of greater looseness. However, when the joint is taken up tight, there is a greater area
of surface between threads with the buttress thread form. As with any threaded pipe assembly,
Teflon® tape should be applied to the thru-hull threads for a watertight connection.
KING-NUT INSTALLATION; The fully assembled valve is threaded onto the bedding coated thruhull
fitting and tightened down by turning either the thru-hull fitting or the king-nut/valve assembly.
A firm, hand-tight mount is sufficient, but if preferred, the nut can be torqued to a maximum of 12
foot-pounds. If it is desired to additionally fasten the king-nut to the backing block with screws,
there is provision for such, but it is completely unnecessary. On the backside of the king-nut there
are four (4) blind ¼” holes. These may be drilled through to the front side before installation t o
allow for round-headed screw fasteners.
VALVE CONNECTIONS: It is recommended that all hose barb connections be made using two
(2) all stainless steel hose clamps. For ½” and ¾” barbs, use 3/8” wide hose clamps. For 1” and
larger connections, use ½” wide hose clamps. If the valve configuration being used has a female
pipe threaded inlet, use care in the installation of the pipe nipple or elbow. Use a Teflon® pipe
sealant. Be sure you are not cross threading by improper alignment and do not torque more than
12 foot-pounds.
MAINTENANCE: FORESPAR® MARELON® Thru-hull/seacocks are corrosion free and provide
great peace of mind in that regard. They are relatively maintenance free. Generally,
lubrication is not required. What is required is to open and close them on a regular basis
(4 times a year minimum). The frequency this is required is determined by two (2) things,
whether the valves are routinely kept open or closed, and the rate of sea growth (weed
and barnacles) in your area. If the rate of fouling is high and the valves are not actuated
regularly, this build up of growth can cause any valve to turn hard or not at all. If the valve
becomes stiff due to lack of use and sea growth build-up, it must be cleaned. The restriction
of flow into the valve may cause harm to the machinery it serves and the valve may
EXTREME EMERGENCIES. All valves are factory pressure tested before shipping. Any
adjustments to the bolts will void this testing and may void warranties.
All MARELON® integrated valves have a removable plug in the handle (white cap with
loop). This plug is made to fit into the external thru-hull (non-screened style only). In an
emergency, this plug can be placed in the thru-hull (water pressure will keep it in) and the
valve disassembled while the boat is in the water. Someone must get wet, but the boat
does not need to be hauled for valve repairs. By tying a lanyard to the cap, you need only
get wet once.

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