Fresh water plumbing on Grand Banks

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JESSEDIVER49

JESSEDIVER49

Senior Member
Joined
May 2, 2013
Messages
187
Location
USA
Vessel Name
Good Vibrations
Vessel Make
Grand Banks Classic 42
I discovered a small, spray leak at a 90-el on the pressurized fresh water line on my GB trawler. It's in the engine room in a very inaccessible location. Will require removal of a bunch of electrical just to get to it. The piping (really tubing) is ~3/8" grey PVC line at a white nylon 90-el. There appears to be a specialty-type SS clamp around PVC line for securing line to fitting.

Can anyone tell me best way to repair this and where to get the fittings and specialty clamps?
 
Can you abandon that section of line? If so, intercept it several feet on either side of the leaky L and splice in a new section. Once abandoned you can then figure out how to remove it if you so choose.
 
We have had a similar problem over the years with the fresh water pipes in our GB. In some instances the "pigeon band" got just loose enough to result in a leak around a joint. I cut it out and replaced with PEX tubing from Lowes. Really blew some joints when I replaced the fresh water pump, more pressure. Was able to dial it back a bit but more joints needed replacing. I carry some extra tubing and PEX connectors and elbows for future leaks.
 
It may be an "oetiker" clamp, often used in fuel systems. It takes a special tool to install but is easy to use in tight quarters. Slice it with a Dremel or cut-off wheel. Stainless Pex clamps are similar but the installation tool is more expensive.
A heavy-duty basin wrench might let you remove the fitting from where the pic was taken.
 
I've done what sunchaser (post #2) has done in the past. Bypass the elbow in unacceptable areas of the fresh water run with soft line with an id that fits over the existing tubing's od. Use hose clamps as needed. The soft line can be inserted into 3/4 hard pvc to get it where it needs to go.
 
I carry 1/2 inch reinforced clear PVC tubing, white nylon hose to hose connectors, clamps and a heat gun. I have a 1974 32 with black tubing and compression fittings. I cut the original tubing with a razor blade and heat it a little, jam the connector into it and replace with clear PVC tubing. Hope that helps you out.
 
On my previous GB I cut the plastic pipe on either side of the leak with a tin snip then installed fresh water hose over both ends of the plastic pipe and secured with hose clamps. An easy fix.
 
Pex is the solution. You can buy the commercial grade, or the HD grade. either way it is better than the old gray stuff originally installed.

There are several DIY 'snap on' connectors. HD has 'sharkbite. There are a couple other brands that work well also. You remove the entire section, and fabricate the equivalent 'ell' piece and fit into place, without having to 'get into' the cramped areas. The great thing about sharkbite is you can push them onto an end of a pipe that you cant touch, but can see in long holes or out of normal reach areas.

PEX is so cheap that replacing 50' is easier than fighting with cramped spaces and difficult runs by just snaking a new long piece in it's place.

There is an equivalent gray push on connection system at most boat supply places. BUT that is continuing using expensive boat supplies.
 
I have a 1990 Grand Banks with the grey freshwater piping. This is Polybutylene, more commonly known as Quest. There was a class action lawsuit in the early 90's involving homes piped with Quest. I have had several leaks over the years and each leak has been at a fitting or connector, not the actual pipe itself. Of course it is always in a terrible spot to get to. My system is mostly 1/2". A 5/8" braided soft nylon hose will slip over the 1/2" Quest pipe and with double clamps will hold for some time. I am slowly replacing all the grey Quest, especially the fittings, with PEX. Crimping PEX in many places is almost impossible in a tight bilge area. I have found that the Sharkbite fittings, while expensive, will work very well if used on the Quest pipe, even though they do not say they will work on polybutylene. They are great for impossible spots as they push on, and come in ell's, Tee's, and straight couplings. Just make sure there are no nicks, cuts, or rough edges on the pipe before the fittings are pushed on. You can then convert bad sections of the Quest to PEX as the needs arise. We are about half way there in converting our freshwater system to PEX.
 
With a boat that gets intermittant use , I have found flaired copper tubing to be the easiest to live with.

Easy to install, no leaks and "stuff" doesn't grow in the copper, as it seems to do in many rubber or plastic piping systems.

That strange smell or taste might not be from the tank..
 
Pex piping on boat

bnoft said:
We have had a similar problem over the years with the fresh water pipes in our GB. In some instances the "pigeon band" got just loose enough to result in a leak around a joint. I cut it out and replaced with PEX tubing from Lowes. Really blew some joints when I replaced the fresh water pump, more pressure. Was able to dial it back a bit but more joints needed replacing. I carry some extra tubing and PEX connectors and elbows for future leaks.
Click to expand...

I have done a lot of piping repairs at the house but never worked with PEX. Do you use the special clamp and tool for securing joints or the fittings that press on with O-ring seal and lock under pressure? Wondering about vibration on boat and integrity of connection with different type fastener designs.
 
PEX to Repair Qest

Seaisleman said:
I have a 1990 Grand Banks with the grey freshwater piping. This is Polybutylene, more commonly known as Quest. There was a class action lawsuit in the early 90's involving homes piped with Quest. I have had several leaks over the years and each leak has been at a fitting or connector, not the actual pipe itself. Of course it is always in a terrible spot to get to. My system is mostly 1/2". A 5/8" braided soft nylon hose will slip over the 1/2" Quest pipe and with double clamps will hold for some time. I am slowly replacing all the grey Quest, especially the fittings, with PEX. Crimping PEX in many places is almost impossible in a tight bilge area. I have found that the Sharkbite fittings, while expensive, will work very well if used on the Quest pipe, even though they do not say they will work on polybutylene. They are great for impossible spots as they push on, and come in ell's, Tee's, and straight couplings. Just make sure there are no nicks, cuts, or rough edges on the pipe before the fittings are pushed on. You can then convert bad sections of the Quest to PEX as the needs arise. We are about half way there in converting our freshwater system to PEX.
Click to expand...

Thanks a lot for your post! And thanks for mention of the "sharkbite" fittings. Are they different than the "P2C" fittings? I just got back from Home Depot are saw the P2C type that slip on without a clamp. They have an O-ring and a design that tightens with water pressure. Appreciate any other tips. I've done a bunch of plumbing using other materials but this will be a first using PEX.
 
Video on Pex
| The Home Depot

When I used PEX, I used the gray plastic screw together fittings. PEX can freeze and not crack.

My boat uses copper for fresh water lines and I like it a lot. It uses flare type nuts with those slide on ring sleeves and brass screw type connectors. Copper is naturally biocidal, and the water on the boat is always good, clean, nice tasting water.
 
Last edited:
Pex requires a crimping tool, about $30 at HD, or you can borrow/rent it for the weekend for $5.
 
PEX has , I believe, 2 types of couplings (connections), one requires a special tool the other is a "shark-bite" threaded connection that can be done by hand.
 
pex also has that screw type connection.

If the tool can be rented, the bands are nicer. Are the bands copper or steel?
 

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