Frozen Seacocks

[Barnacle Bob]

How to unfreeze tapered seacocks while the boat is in the water?

Heat? Penetrating oil? Sledge hammer? Blow torch... heat gun? I know the boat should be hauled out, but in Japan they want $4,000.00 just to haul a 60 foot boat out of the water.

Maybe I should just replace the seacock... but there seems to be bolts that go through the pad and the hull and the base of the seacock.

Fortunately this boat was built in 1973 when they made boat hulls with solid laminate... the hull is one inch thick fiberglass.

I'd like to replace the bronze seacocks with marlon... but Forspar says don't attach a marlon seacock to a bronze thruhull, but they don't say why...

[cyclops]

Call them and ask for technical assistance.

[PowerTech]

if they are stuck open and you need to shut them put a pipe on the handel and push on them.but watch the hull and sea cock for to mutch flexing it could break off.It will take a good feel to know when to give up or when to push some more.having a stuck open sea cock is not the end of the world a stuck closed one is more of a bitch.you can take care of it at your next haul out.i put them in a few times in the water but that way sucks and you usualy cant do it that way.If you are being inspected or something they wont like that but if not you can work around a stupid stuck sea cock and wait until your next haul out to tackel it.if you have to service the engine or pump or whatever the sea cock is for and it requiers shuting the sea cock you can just plug the hose with some thing,I do that all the time i do that some times when the sea cock is in a pain in the ass spot to get to.If you had to change the hose for some reason before you can change the sea cock just do it fast i have done that plenty of times and there all still floating.And the Sea cocks i allways buy are just big brass or bronze i dont know ball valves with stainless and teflon guts and handel.nothing fancy and work very well.

[Barnacle Bob]

Understand... but I want the boat to be safe and in the event of a hose rupturing, etc. while underway out at sea, I want to be able to quickly close the seacocks. The ones for cooling water for the engines and airconditioning systems,etc... they are working and seem to have a different teflon ball or something that doesn't corrode. But there are still some tapered ones that are below the waterline that connect to the large muffliers, etc. and they are frozen open... but if I ever need to close them... they won't budge. I was thinking to plug them from the outside and change the seacocks with more modern types if I can't unfreeze them. I heard that heat will free them... maybe from a heat gun... As mentioned... the hull is 1 inch thick solid laminate fiberglass. When the portholes were cut out of the hull during manufacturing, the original owner took the cut outs to a firing range on a Navy base and used them for target practice. The bullets were unable to go through and only marked the gel coat. So, the hull is very strong.

Also, I don't know how the thruhulls are fixed in place... if I unscrew the seacock of the thread... I don't want the thruhull to come out... Is it bonded in? I suspect not or maybe just bonded in with some bedding compound.

I'm also wondering why in a fiberglass boat they used a wood backing block for the flange base of the seacock...I would rather use a high density plastic foam... synthetic wood... so there would never be a concern about the wood block rotting.

Sometimes, I wonder why manufactures cut corners in such important areas. I also noticed that instead of putting in metal backing plates in the inside for the deck stantions, they just used plywood that is now rotting. I will replace them all with stainless steel backing plates. I guess cause they are out of sight... they can get away with it.

[trawlercatbuild]

Loosen the nut at the end of the taper, slightly, and tap end of threaded shaft with small sledge, careful not to damager threads. Then tap around entire body. As pressure on taper is relieved you may break loose. I have also had luck with removing 1/8" NPT plugs, generally found on all seacocks as drains, and spraying in lubricant or packing in grease. Marelon fittings use there own proprietary thread so you must stick with the Marelon in any given assembly. Good Luck

[Barnacle Bob]

Thanks for the info.

I found the following tech tip from Forspar that should be of interests to many:

Tech Tip



Marelon® Valves on Bronze Thru-Hulls, (It can be done!)


For years, boat builders, boat yards and repair facilities have installed replacement valves on existing thru-hulls. This is a common practice as it is less labor intensive than removing and replacing a thru-hull that has been in a boat for years. As long as the old bronze thru-hull is sound (no electrolysis or corrosion damage) then why go through the trouble, added labor and expense of replacing it.

Marelon® Ball Valves (MF 850 & 849 series) can and have been installed on bronze thru-hulls for years. Even some new production boat builders are installing our Marelon Integrated valves on bronze and stainless steel thru-hulls as standard equipment. High quality blue-water fishing boat builders such as Grady-White Boats are using Forespar® Marelon® "93" series Integrated valve systems on bronze thru-hulls without any trouble.

Tips:

Be sure the bronze thru-hull is sound
Be sure the threads are clean and all old sealant is removed
Do not cross-thread! Bronze will "cut" threads if forced onto Marelon®
Use adequate Teflon® pipe tape or plumber’s dope for thread sealant
Be sure you do not "violate" the sealant on the thru-hull by twisting in the hull
Do not over-tighten the valve. "Hand tight" is all that is needed
Properly bond or ground the bronze thru-hull. It is still subject to electrolysis and corrosion, even with the Marelon® valve installed
For the "Ultimate" in corrosion control and weight savings, change all thru-hulls to Marelon® as well as the valves!
Note: There are a number of foreign-made bronze thru-hulls on the market. Forespar® cannot guarantee thread compatibility on these inferior thru-hulls.

[Willallison]

If all else fails, you could always install a second, in line valve immediately after the seacock until your next haul-out. The change-over can be a bit frightening - it's amazing how much water can come thru such a small hole!... but it can certainly be done.... just be ready with a hammer and a wooden bung to stem the flow!

[mackid068]

You really ought to take it out, it's not worth damaging a boat worth thousands just over a matter of $4,000, despite that $4k is a lot of money.

[Willallison]

just another thought... jump over the side and bang in a wooden bung from the outside. That way you can pull the sea-coack apart without fear of sinking

[Barnacle Bob]

Looks like some good news from Forspar. I'm pasting their reply as follows:

you can attach Marelon to bronze. The only caveat is to be sure you do not cross thread! The bronze will win every time. Use Teflon tape or pipe dope (plumber’s putty) to seal the threads. When removing the old bronze valves, be sure you do not allow the thru-hull to turn. This will cause a leak around the thru-hull as the sealant will be torn and compromised if the thru hull moves. Install the Marelon valves HAND TIGHT, no tools should be required or used on the Marelon valves.

As to the thread form-

We offer the MF 849 1.5” flanged sea-cocks and 850 1” thru 2” series ball valves in BSP parallel or NPT parallel threads. The ½” and ¾” sizes are NPP only as these sizes are almost identical to BSP threads. There are no other thread-forms available.

I do not have a way of verifying your thread-form. You will need to confirm what you have.

We sell our fittings in Japan thru Industrial Suppliers Company in Tokyo. By way of this email I am asking ISCO to contact you concerning your requirements.

Best regards,

Art Bandy

Forespar