400: Lagoon 400 Technical Notice - Nacelle Drainage

[tuskie]

It seems to me that the Lagoon Notice requires that there are two sets of holes to drill in order to drain the area under the shelf that supports the water tank. One set internally to allow water to exit from under the water tank shelf and a second set to allow drainage externally via the lower bridge deck area.

The water tank shelf is not a structurally important part of the hull. It would serve some small part in enhancing rigidity in the horizontal plane. The big issue is that the shelf is attached to the main bulkhead. Water trapped under the shelf may cause rot in this bulkhead. It is very difficult to detect rot in this area without removing the water tank shelf.

I have not yet cut into my nacelle area, so can only speculate on the reasons for this rot. Lagoon has confirmed the first reason; poor drainage in the area. This traps fresh water, the first requisite for rot. The other ingredient is timber; especially softwoods.

I have performed the "cut out rotten timber and rebuild" job on several boats, from transoms of small runabouts to engine beds and stringers in motor launches. I'm guessing the L400 nacelle will follow a similiar theme as to its cause.

Usually the timber is glassed in, glassed over and painted with flow coat. All good and sealed water tight, so no rot. No! Eventually, unerringly and sometimes quickly, water finds its way in through breaches in the fibreglass. Perhaps it's an air bubble in the glass, perhaps a hairline crack, damage from a dropped anchor, maybe an unsealed fitting. The glassed in timber "breathes", expanding and expelling air in hot weather through these breaches. Cooling down and sucking in moisture in the form of water vapour. This is all that is required to start wood rot. Fungal spores will germinate and produce microscopic root like "hyphae" which penetrate the wood and chemically dissolve it, allowing more water vapour to enter. Finally, when the fungal structure is advanced enough, "fruiting bodies" are produced. These are in the form of mushroom or bracket structures, designed to release spores for wind or water distribution. The fungal rot is well developed when these appear. The fibreglass that was sealing the water out, now is sealing it in, preventing the timber from drying out and expediting the rot. It's my experience that there is usually a lot more rot than first thought, once you start cutting and probing.

How to prevent this happening again? Very complicated! A few options; avoiding timber, is my favourite. "No wood, no rot" is my motto. Replace with high density foam and use more layers of glass to regain the strength of the original timber layup. If you're dead keen on using dead trees, cut out to shape then seal all round with a preservative/sealer such as "Everdure" before glassing in. Glass in well, roll meticulously using resin rich lay ups. Make sure freshwater drains and doesn't lay against the structure. Don't screw in ply, skimp on glass and paint on flow coat to hide your sins. Stick your head into the nacelle locker of your L400 and decide how well the job was performed.

[peterp]

Originally Posted by tuskie

Very interesting, Peterp. I have recently spoken to the technical guy at the new Lagoon dealership in Sydney regarding getting Lagoon to pay for a warranty fix on what I believe to be an inherent fault. He denied any knowledge of the Technical Notice and said he would ask Lagoon about it.

Was your kit supplied by the current or previous Lagoon dealer?

It's good to see that some owners have been informed about this issue and possible rectification, but many haven't. My boat may be growing mushrooms due to rot, but I don't like being treated like a mushroom. You know, kept in the dark and fed BS.

The bottom line is that one way or another, my boat will get the whole area ripped our, checked for rot and repaired to a level far superior to the original. Drainage will be addressed from the inside out rather than the way Lagoon suggest. That way I'll know the drain holes are properly positioned.

Hello Tuskie, I received my 'kit' from Vic Sail in Sydney the original Lagoon distributors who I purchased my L400 from brand new, not the new distributors 'TMG', they only took over late last year, so makes sense they would not be aware of any warranty issues not on their watch so to speak. I have been talking to them recently re possibly purchasing the new 42S, they seem to be OK folk but time will tell of course. Tuskie did you buy your L400 new or used I just wonder if the warranty covers both the first owner and subsequent owners in the event of asking Lagoon to pay for replacing the water tank support floor, the other thing to consider is I think the Lagoon hull warranty is five years, my L400 is now about 5.5 years old.

[peterp]

I haven't removed my water tanks to do a thorough check of the problem as yet but on a general look over I cannot see any sign of the problem, mine is hull 93, but thinking about it I cant see how water can get in on my L400, for example when I fill the water tanks I fill from the deck filler which has a pipe connection to the first tank then when that fills the water then overflows to the second then a final over flow pipe allows the water to flow out the top to the sea, no water escapes to the tank floor at all. In front of my starboard tank I store two foldaway bikes which are both housed in a canvas bag as well as other stuff, I regularly check for moisture particularly after washing as I don't want those bags to get wet as then the bikes would get rusty, I have never found any moisture and the bikes aren't rusty, the lid seals are as new I know that as I regularly clean the locker lid and check the seals, must say we only sail around the bay in mostly good weather so my L400 has been used very lightly, engine hours about 270, so maybe a craft with high use and sailed in rough ocean stuff may well have water in the locker, I don't know.

[monte]

We had the bulletin forwarded by our dealer a few months ago. We arranged for the local dealer in Martinique to do the fix. I helped the technician drill the holes and fit the covers to the lower holes. Simple enough job, about an hour to complete. Lagoon covered the cost. I'd guess around 60l of water flowed out of the holes once drilled. Hard to be exact but a a fairly good flow for 10 minutes or so.

[peterp]

Originally Posted by monte

We had the bulletin forwarded by our dealer a few months ago. We arranged for the local dealer in Martinique to do the fix. I helped the technician drill the holes and fit the covers to the lower holes. Simple enough job, about an hour to complete. Lagoon covered the cost. I'd guess around 60l of water flowed out of the holes once drilled. Hard to be exact but a a fairly good flow for 10 minutes or so.

Hello Monty, tell me did you see any signs of rot prior to fitting the mod, also just to help my understanding where was the 60 ltr sitting prior to drilling.
Regards Peter

[peterp]

Monty, meant to ask could you provide any photo's of your finished job, which would be helpful for my understanding and others I would imagine.

[tuskie]

Originally Posted by peterp

Hello Tuskie, I received my 'kit' from Vic Sail in Sydney the original Lagoon distributors who I purchased my L400 from brand new, not the new distributors 'TMG', they only took over late last year, so makes sense they would not be aware of any warranty issues not on their watch so to speak. I have been talking to them recently re possibly purchasing the new 42S, they seem to be OK folk but time will tell of course. Tuskie did you buy your L400 new or used I just wonder if the warranty covers both the first owner and subsequent owners in the event of asking Lagoon to pay for replacing the water tank support floor, the other thing to consider is I think the Lagoon hull warranty is five years, my L400 is now about 5.5 years old.

You'll understand if I don't wish to discuss too much about warranty at this stage, as negotiations are (hopefully) proceeding.

My boat is hull #141, bought by me 2.5 years old. It was originally purchased in France and shipped to Australia. Rot appeared well inside the 5 year period. TMG were the Lagoon dealership in Australia at the time the Technical Bulletin was released. Is the water tank shelf and main bulkhead part of the hull? I think so, but opinions apparently differ. Are dealers who have not sold a boat obliged to undertake warranty repairs on boats of that brand? Who knows?, but it's not the first time that ducking and buck passing between Lagoon and their dealers has featured in this forum.

Thanks Monte. You have substantiated that, (a) water is pooling, unseen, in this area, and (b) dealers that have not actually sold the boat are willing or obliged to fix the problem, through Lagoon, as they are that brand's local representative.

In view of point (a), I would caution owners who look in the nacelle hatch area and decide that all is sound and dry to think again. My boat looked fine until the rot produced soft areas and evidence of fungus. I hope that the "Lagoon fix", actually works to prevent rot in this area. I'd strongly suggest that any Lagoon 400 owners undertake the drainage procedure, AND pay a competent surveyor to climb in there with a moisture meter. Then access the rear of the main bulkhead via the inspection hatches next to the Nav station and in the port forward cabin. If high moisture levels are detected in the timber get it replaced. If the boat is under 5 years old, knock on the dealer's door.

[AZ_Zoner]

Originally Posted by monte

We had the bulletin forwarded by our dealer a few months ago. We arranged for the local dealer in Martinique to do the fix. I helped the technician drill the holes and fit the covers to the lower holes. Simple enough job, about an hour to complete. Lagoon covered the cost. I'd guess around 60l of water flowed out of the holes once drilled. Hard to be exact but a a fairly good flow for 10 minutes or so.

Monte,
This sounds like something I should take care of before I leave Martinique.
Can you give me the details of who you used and there location?
We've got a haul out on the 19th so maybe I can talk the ship yard in Le Marin to take care of this for me.

Craig

[monte]

Craig, have a chat to Hubert, the local lagoon rep. net-boat@wanadoo.fr It will be a bit easier to do while the boat is hauled. Lagoon supply a kit but it's basically just two covers for the holes, probably just a few dollars from the chandler.
The water that drained was fresh and mostly clean so I assume it's rainwater coming in from deck joins and window seals that has no way to escape. We drilled the front locker hole right through the ply rather than removing the small ply panel forward of the water tanks.

[monte]

Peter, I assume the bridgedeck is fitted to the face of the hulls and most of the water was at that junction, as well as in the central nacelle. I will probably remove some panels and take a look as well.

[arsenelupiga]

Originally Posted by monte

Craig, have a chat to Hubert, the local lagoon rep. net-boat@wanadoo.fr It will be a bit easier to do while the boat is hauled. Lagoon supply a kit but it's basically just two covers for the holes, probably just a few dollars from the chandler.
The water that drained was fresh and mostly clean so I assume it's rainwater coming in from deck joins and window seals that has no way to escape. We drilled the front locker hole right through the ply rather than removing the small ply panel forward of the water tanks.

that makes sense. I have discovered water leak from one starboard window. Water trace was visible under main bathroom sink, left bottom opening. Always wondered where this water ended up as it was nothing in bilge. Little water trace established itself when raining, before we fixed window leak. Now I knw where this water likely ended up.

Looks to me it is required fix.

[peterp]

Originally Posted by monte

Peter, I assume the bridgedeck is fitted to the face of the hulls and most of the water was at that junction, as well as in the central nacelle. I will probably remove some panels and take a look as well.

Thanks Monty very much indeed, I must confess I am completely lost on this one, I can't grasp where this water is coming from or where it is pooling out of view. kindly nominate me as drongo of the year. I will be visiting my craft next weekend I will have another thorough look and poke everything with a screwdriver to try and find this problem which at this point I don't think I have, stand by for an update. Regards Peter

[mayanman]

does anyone think this would work... if you have NO rot.... couldn't you drill hole in top under water tank and bottom ....fill with this expanding foam and seal hole in top and bottom ...

RDL 909 - Foam & Fill Expanding Polyurethane Sealant - 12oz - Champagne ( 909 ) by Red Devil

Fill in the gaps and cracks with this unique, expands-as-it-cures polyurethane sealant. Indoor/outdoor insulating foam forms an airtight, waterproof bond, sealing out drafts, moisture and pests. Aerosol delivery system ensures quick and easy application. For use on aluminum, clay, concrete, fiberglass and stone, as well as finished/painted and unfinished/unpainted wood. Color(s): Champagne; Capacity (Weight): 12 oz; Packing Type: Aerosol Can

[mayanman]

RDL 909 - Foam & Fill Expanding Polyurethane Sealant - 12oz - Champagne ( 909 ) by Red Devil

I would only do if there was no rot....

would this work ?......drill hole under water tank...and below and fill with expanding foam until you see it coming out bottom..

[tuskie]

Originally Posted by mayanman

RDL 909 - Foam & Fill Expanding Polyurethane Sealant - 12oz - Champagne ( 909 ) by Red Devil

I would only do if there was no rot....

would this work ?......drill hole under water tank...and below and fill with expanding foam until you see it coming out bottom..

How do you know that there is no rot? The drain holes will allow water to escape and air flow to dry out the space. This is the best solution provided that rot has not already started from years of trapped water in contact with poor quality timber ply.

Expanding polyurethane foam may exacerbate any problem by further sealing in water. As well, great care needs to be taken when applying it to confined spaces. When it has a large surface to act upon the expansion forces can cause damage.
I once saw a speedboat that it's deck completely detached and lifted from the hull because someone had poured this foam into the subfloor area. The boat in question had a "soft " deck due to rot in the subfloor stringers and I'm told the owner tried a "cheap fix" before selling. There's a moral to this story.