"Watertight" Engine Room Compartment leaks.

[YPSILANTI]

Greetings folks,
The engine room My 50 ft Cat has a fiberglass wall which separates the engine room from the rest of the vessel, as does the bow compartment. The two engine room have their own bilge pumps. My fuel pipes run through the wall by means of a 50mm PVC sleeve pipe towards the main fuel tanks situated mid-ship in each hull.

However, I put a hose into the engine room to wash it and discovered that the watertight compartment "isnt so watertight" and water flowed through the 50 mm pipe to the main bilge pumps mid-ship.

1. How do I best seal the three smaller fuel lines situated in the larger PVC sleeve. What product / system should I use.
2. Is this method of having a sleeve through a watertight compartment O.K or should I be re routing the lines?

Thank you.
Regards
Mike

[Jeannius]

3M 5200 will do it very nicely. Flows easily enough to get everywhere you want, and usually places you don't want as well so have acetone and cloths ready. Remains flexible and very strong when set so seal won't be broken if your hull flexes a bit.

[cal40john]

Originally Posted by Jeannius

3M 5200 will do it very nicely. Flows easily enough to get everywhere you want, and usually places you don't want as well so have acetone and cloths ready. Remains flexible and very strong when set so seal won't be broken if your hull flexes a bit.

5200 seems like overkill to me. It will be a real pain when maintenance time comes.

4200

expanding foam

slitted rubber plug with hole for hose drilled in it

[Kokanee]

I would suggest running the lines through a 3 hole grommet of the correct size such as this: Echo 3 Hole Fuel Tank Grommet | eBay

Or make your own by drilling out a blank rubber plug.


Another option is glassing over the big hole and installing individual barb to barb bulkhead fittings for each line.

[2Hulls]

Originally Posted by YPSILANTI

2. Is this method of having a sleeve through a watertight compartment O.K or should I be re routing the lines?

As you've already discovered, it's not OK in your case. However, it might be OK if the elevation of the bulkhead penetration sleeves was such that water could not get that high without the boat being already swamped. One could easily argue that it's a poor design to have flow-through sleeves situated too low to allow a single flooded compartment to flood an adjacent compartment. Boat building 101. Even if flow-through capable sleeves were sufficiently high, common sense dictates that sealants be utilized for those unforeseen circumstances. It would be interesting to see what the various boat building standards - CE, ABYC, etc. - say about this (if anything).

Dave

[Tiemates]

Or try Sugru https://sugru.com

It's easy to use, waterproof, doesn't get all over everything and can be fairly easily removed, if required

[Rough Magic]

The fuel lines will heat and cool, expand and contract every time you start the engine. The return fuel line, which carries the fuel used to cool the injectors, will get very warm. What ever method you use, the sealant has to cope with vibration, expansion, and heat.

I'd look at Sikaflex 292i, approved for marine construction.

[jldunn86]

Originally Posted by Kokanee

I would suggest running the lines through a 3 hole grommet of the correct size such as this: Echo 3 Hole Fuel Tank Grommet | eBay

Or make your own by drilling out a blank rubber plug.


Another option is glassing over the big hole and installing individual barb to barb bulkhead fittings for each line.

X2

or the bulkhead fitting...

[TheThunderbird]

That water is passing through... ok

But where is it coming from ?????

[YPSILANTI]

I intentionally put water into the engine room with a hose pipe . The sleeve is situated lower than the engine mountings so I was able to fill above the sleeve to test it.

Thanks so much for all the replies. The various options are an education on what can be done. Ill give the Sikaflex a try as its readily available here in South Africa.

Much appreciated.

[hellosailor]

I'd take a can of urethane foam (sold as insulation and caulking), sold under the name "Great Stuff" here in the US, and just shoot the foam into the outer 50mm pipe, using the longest nozzle to get it down a bit. The foam will expand to fill, seal, and block the pipe without crushing it or your fuel lines, and you'll have a solid plug in there, which will be adhered so well that it would take a LOT of water pressure to move it out.


You can dig it out, or mash it up, using a dowel or screwdriver at a later date if you need to get it out again. But it sounds like you need a semi-permanent plug that will remain in place until the fuel lines need to be changed.


The "proper" way to penetrate a bulkhead would be to have a metal shop fabricate a plate with three pipe nipples welded into it. Fuel lines to be attached (screwed on, banjo clamps, whatever) on either side, after the plate was welded into the engine room bulkhead. Fiberglass...no welding, but the same idea.


Not a terribly difficult long-term fix to "do it right".

[Palarran]

For what it's worth, I filled mine with silicone sealant and their fine. There is NO WAY water is going through the pipes in enough amount to make a difference to the main cabin. Don't over think this as it's an easy fix and there is no pressure on the pipe.

[Charles G]

Hi Mike,
Would "Great Stuff" foam help. It's closed cell so it will not absorb water and can easily be removed.
Charles