Marelon Seacock

I have a question for those of you who have Marelon seacocks on main raw water intake.

I'm trying to determine if any Marelon seacocks retain water within the housing of the seacock when in a closed position. I realize there will be raw water both upstream and downstream of the closed ball valve - but what about within the seacock? For example, my bronze seacocks have a "bulge" that will retain a little water when you close them. They also have a small drain that allows you to drain that water out if desired and inject grease.

I've never seen anything that looks like a drain in the Marelon - so it seems logical that no water is retained once you close it, but I'm looking for confirmation.

Thanks.

i Would think anything with a "ball" or cylinder type valve will retain water. There is a hole in the ball or cylinder that is lined up with the thru hull when open and will still be full of water when closed.

Ken

You know, I like to think I'm a fairly intelligent and logical guy - but I totally missed the fact that the hole in the cylinder must have water in it when it's closed. That's obviously why good quality bronze seacocks have a drain that is lined up with that.

Now I fell stupid for wondering if water was retained when closed. I guess my question should be "is there enough water retained to damage the seacock when it freezes?"

The answer I got from Marelon was "it needs to be -40 degrees for an extended period of time before the seacock is damaged" - but I think they are just talking about the material its self, not damaged from expanding water.

Thanks for the reply, Ken.

I never noticed they didn’t have a drain. Maybe Marlon is flexible enough that the expanding ice won’t damage it. I’ve lived in South Florida all my life so I have no experience with water freezing outside of my refrigerator.

HopCar said:

Maybe Marlon is flexible enough that the expanding ice won’t damage it.

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That's what I'm wondering. I understand water expands around 9% when frozen - so that seems like a lot of expansion if the water takes up all of the available space BEFORE freezing.

"Good" marine ball valves have a small screw that drains the ball cavity when closed for the winter if stored in the water. I think that this is limited to 1" and larger valves. For smaller 3/4" valves I have blown through a piece of hose attached while open and quickly closed it.

These "good" ball valves are made by Perko or Groco. I don't think Apollo/Conbraco valves have a drain port.


I generally like Maralon valves, but I don't think that they have a drain port either.


David

djmarchand said:

"Good" marine ball valves have a small screw that drains the ball cavity when closed for the winter if stored in the water. I think that this is limited to 1" and larger valves. For smaller 3/4" valves I have blown through a piece of hose attached while open and quickly closed it.

These "good" ball valves are made by Perko or Groco. I don't think Apollo/Conbraco valves have a drain port.


I generally like Maralon valves, but I don't think that they have a drain port either.


David

Click to expand...

The Apollo/Conbraco flanged seacocks do have drain plugs on all sizes as do the Groco seacocks.

I would highly doubt that merelon can take freezing without specific information to the contrary.

Holding water is irrelevant to David's point if the boat is stored on land. I know some are on the coast but everything around here is hauled then the vales drain when opened. If in fact my boat wintered in the water I would want valves with drains.

According to Forespar "I have never had a valve fail due to having water left inside or the boat kept in the water during an east coast winter."

Which is not the same as saying it can handle the freeze. I think I have a solution in spite of that ringing endorsement.

As noted elsewhere, winterization is always geographic. If I were in Canada I wouldn't leave my boat in the water in the winter either. Here in VA we are borderline - every year there are a number days that dip into freezing temps and only a few days where the high temp doesn't climb above salt water freezing temp.

I'm using Marelon because I'm building an aluminum boat and don't want to contend with bronze. Otherwise I'd stick with a quality bronze unit.

OK, that makes sense. Marelon is a good choice for an aluminum boat. But lets talk about thru hull valves freezing, mostly from a theoretical perspective but with a bit of practical experience thrown in:


Thruhull valves with a ball pocket full of water can only freeze and burst if they get cold enough, duh!! They can get cold enough if the inside temp of the boat surrounding the thru hull is low enough or the water below it is frozen.


In Virginia it is very unlikely that the water will freeze 1-2" thick. The outer thru hull mushroom will always be in liquid water which will be above he freezing point of the water in the ball pocket. In my experience in Oriental, NC the air temp inside the bilge will be above the freezing point. In Virginia to be safe I would keep a small bilge heater going in the coldest of days to be sure that it doesn't get down to freezing.


David

David, that's exactly my thoughts. My intake is ~30" below the surface and won't freeze here. The ER MIGHT drop into the range to freeze salt water from time to time, but a small heater will help keep temps up.

Additionally, I'm looking at a way to weld a water intake standpipe that would allow the seacock to be just a hair above the resting waterline. If we can engineer that to be strong enough and resist vibration - it's the best solution for a metal boat. All the major problems with Marelon are mitigated if it is not submerged all the time.

If I can create the standpipe, then my issue becomes prevention of freezing in the standpipe - which is easier than dealing with the Marelon.