GB 42 Seacocks

GBNI · 10-08-2021, 06:43 PM

Looking at buying a 1998 GB42 MY but am concerned at the state of nearly all the thru hull seacocks.
Any advice?

There are two which are an unfamiliar type to me both marked “out” They are cylindrical with valve at base.
What are these for?

Blissboat · 10-08-2021, 06:51 PM

Quote:

Originally Posted by GBNI

Looking at buying a 1998 GB42 MY but am concerned at the state of nearly all the thru hull seacocks.
Any advice?

A qualified marine surveyor will answer that question and many more. Don't buy a twenty-three year old boat without making a satisfactory survey one of the contingencies in your purchase agreement.

GBNI · 10-08-2021, 06:54 PM

Should have said that I will be getting a full survey prior to agreeing anything

Jc180 · 10-09-2021, 04:38 PM

Looked at a number of Grand Banks recently; ended up buying another brand boat. But all of the GBs we looked at had the original Groco rubber valves that have a tee handle to loosen, tighten (loosen to rotate valve, tighten after opening or closing). Typically, the valves were left in the open position. Tried to close a few, were frozen place. Obsolete, Groco does not offer replacement parts. We also had these valves in our motorsailer. They were open when we bought the boat. We were able to close when we hauled for the winter, but had a h*ll of a time getting them to reopen in the Spring. We opted to replace with bronze ball valves (bronze body, stainless steel balls). The failure mechanism is swelling rubber over time. The cylindrical shaped devices you saw are strainers with valves below (suspect label outlet was the outlet flow direction for strainer, also suspect they were engine and gen set cooling water inlets).

Hopefully not the case for the boat you are looking (and I’m probably going to draw fire from GBs owners), but GBs can be pristine above the cabin sole, but a rusty mess in the engine room. Especially boats advertised as professionally maintained.

Good luck in your search. We have been disappointed in Surveyors. Use of your own eyes and ears and continuing to ask questions are well advised!

Jc180 · 10-09-2021, 04:59 PM

Oh and I should mention, being able to close seacocks is a big safety deal. Imagine a leak in a hose, etc and not being able to close seacock to isolate! Have witnessed boats sinking, sunk. We always close seacocks if we intend to be away from boat for more than a week or two.

Cigatoo · 10-09-2021, 05:06 PM

It probably has the GROCO SV Series seacocks as JC mentioned above. Ours are all SV Series seacocks. Parts are no longer available. However the ones that I have pulled apart to service have been easily serviced as outlined in the attached pdf from GROCO. Be sure to use silicone grease.

Jc180 · 10-09-2021, 05:27 PM

Quote:

Originally Posted by Cigatoo

It probably has the GROCO SV Series seacocks as JC mentioned above. Ours are all SV Series seacocks. Parts are no longer available. However the ones that I have pulled apart to service have been easily serviced as outlined in the attached pdf from GROCO. Be sure to use silicone grease.

Thanks, you are to be commended for maintaining valves. Note though that Groco recommends replacing if rubber deformed. No replacements available. In my own experience, deformation was significant. Thought about chocking up in lathe and turning off bumps. Opted to replace, but agree could be refurbished if boat owner took initiative.

JDonald · 11-09-2021, 07:02 PM

We bought our boat a few years ago. It had the SV series seacocks. I have had a few reworked but mostly I plan to replace them all. Every time I haul out I replace 2-3. It's not something to tackle all at once unless you have to. Were were able to rebuild a few but like one of the post stated those rubber pieces are no longer available. I have seen them on EBAY once. I thought the SV series was discontinued by 1998. I may be wrong.

HopCar · 11-09-2021, 08:12 PM

Ask the surveyor about the seacocks. If they are a problem, use that to negotiate a lower price. It’s probably not a reason not to buy the boat.

DennisB1 · 11-09-2021, 09:15 PM

I have theSV series strainers in my 1990 GB. Worry is will end retainer plate screws come out with out breakage. If you can remove the rubber plug you can gently sand the rubber cylinder to some rough areas. I would also clean up the interior bore by hand sanding. Reinstall using a silicone grease which will not cause the rubber to swell. The housing to be in a acceptable condition with no corrosion. I saw this process in another thread.recently. My plan for the next bailout.