500: Lagoon 500 Nearly Sunk

[colemj]

Actually, the pressure could be somewhat high if the compartment was filled with water and was below water. But the silicon plug is on the pressure end of the conduit, and I would expect the water pressure to distort it as it tried to push it through the pipe - with the result that it plugs in tighter. I think water will still come through, but it will be a slow and small leak.

Mark

[ArtM]

Originally Posted by meyermm

I have been told numeros times this cannot happen and I believe everything I am told

I've heard that if you attach a few tons of lead to the bottoms of the hulls, then poke a few holes in them, then a multihull might sink.

The same is true of monohulls, which typically come preconfigured with a few tons of lead attached to the bottom and holes poked through the hulls.

[Palarran]

Originally Posted by colemj

Actually, the pressure could be somewhat high if the compartment was filled with water and was below water.
Mark

I really wasn't very good at math but if memory is right you would be dealing in inches of water pressure. We use that for measuring gas pressure on furnaces. One square inch of water pressure is .036 psi. If the tube was 12 inches under water it would have .036 psi x 12 exerted on it, or about 1/2 pound of pressure. If 2' under, it's still less than 1 pound of pressure. Maybe I'm wrong with the math? I do know that I can put my finger over the end of a hose with 40psi on it and stop the water flow so I'd guess it wouldn't be too hard to stop 1 psi.

The issue isn't what you would plug the tubes with because a rag would do just fine. It's actually doing it when your engine compartment is already flooded. Or even figuring it out that is where the water is coming from.

Some of the comments about cats sinking - are right. I wouldn't doubt mine would with all the weight it has on board. I'd guess more would than wouldn't. That's really not the point - who cares. Don't get put in the situation in the first place.

[Sand crab]

Yeah, don't hire a captain that has already run over the dinghy painter a couple of times.

[Wraith_Mac]

Originally Posted by minaret

Read it again, both hulls were lying on the bottom. And they specifically state repeatedly that there was no reserve buoyancy left above the point to which she filled, only rigging. This boat sank. The skipper who brought the boat out from France, and who salvaged her, stated repeatedly that the boat would have sunk to the bottom if it hadn't been beached.


There are plenty of monos with positive floatation. The FD12 comes to mind (50' cruiser, not a dinghy). And guess what, since people tend to have a healthy skepticism about monos with PF, the builders actually tested it, took pictures and video, and published all the relevant tables and info. So you know that it is indeed the case. In fact they give you a table that shows how low the boat will float at various loads when compromised. Never ever seen a multi builder do that, because it would challenge the propaganda line they've tried so hard to develop, ie all multis float when compromised and float high enough that we don't need to discuss that.

Try looking up Ian Farrier's site.
Banning ALL propaganda and a having a rigorous testing standard with published results would be ideal but then I'm a hopeless idealist.
Cheers,
Mac

[cll2]

Thanks to all for the welcome to the forum. I came upon the link to the L500 situation while researching Lagoons and other brands in general as I'm currently considering purchasing a used cat in the next year or so. At this point my interest is centered around the L440, though my research continues. Thanks for all the great info that can be found here on the forum.

[Lagoon4us]

Originally Posted by Emmalina

At this point I think everybody with a lagoon should buy some expanding sealant and get busy ........ I think anybody who has cruised enough will admit to chomping thier painter..... Didn't know saildrives were so flimsy though.. Stick with my shaft drive thanks

Ask around any Marina, this year i was having a beer with a guy in Gouvia Marina, Corfu, Greek Islands he had just relaunched his boat after a sheet rope had gone over the side wrapped around the prop and pulled the shaft out of the hull. THIS WAS A CONVENTIONAL ENGINE/GEARBOX/SHAFT/PROP SET-UP. ie NOT a sail drive.

This kind of incident can occur no matter the configuration of drive.

The wayward rope is the issue not the drive,

With regard to the Incident that this thread is all about, are we to believe that after such an incident it was that impossible to block a 40mm diameter hole from the other side and contain the waters ingress to the offending engine room????????

Where were the tapered timber plugs?

BAD seamanship but that's just my opinion was the cause of this and bad legal advice followed from someone wanting to blame someone else!!!!!


Cheers

[Oliver L.]

Parallan,

I am a metric guy, so I'll do it the easy way for me. I think the largest opening is about 100 mm (4") in diameter. Makes a surface of 76 square centimeters. Let's assume that 1 m (3' and a bit) is the lowest you can put this opening under water without opening other avenues for the water to get into the main cabin (flooded cockpit etc). That makes 0.1 kg of pressure per square centimeter. So the total force on the plug would be around 8 kg or 17 lbs.

When I tried to stick a few more cables and hoses through the hole, I certainly used a lot more force than that, and none of the other hoses budged. So in my mind it is clear that - whether it is silicone or foam - any halfway decent filler will stay in place and allow you to get things fixed.

Now I am venturing into the realm of speculation. So the saildrive was lifted up forcefully together with the engine. Wouldn't cutting the goddamn painter have resulted in both reseating at least close to their original position - which would then have opened up the possibility of reducing the water ingress further by plugging the gap with towels, clothes - whatever comes handy? Admitted, I would not have gone swimming out there, but after beaching the boat I think I would have checked whether I can plug it better from below.

Oliver

[monte]

If you read the survey report you will see pictures of the bulkhead in question. The owner had air conditioning fitted after the factory. They drilled holes to run pipes from the engine bay into the hull. They didn't seal the holes at all. It's hard to understand how the owner can argue that the bulkheads should be watertight, yet installs equipment and doesn't make them watertight.
Not trying to bag the owner, just trying to look at things in perspective. It's a shitty deal and I feel for the guy.

[Lagoon4us]

Something to consider, the top of a Lagoon's engine room has sound deadened foam glued to a timber flap/door, once the water get's over this level it can flow to the opposite engine room.

Also once it gets to that level it can flow forward under the cockpit floor into the saloon.

The only remedy is in prior action i.e. fit a pump in engine room and seal all potential leaks through the bulkhead.

The water WILL follow the path i described above regardless IF allowed to reach the height.

ONLY a water tight hatch above the engine space (not the deck level but the ply doors above) will make it a 'secure' flooded area and these boats along with most others DO NOT LEND their way to achieving this easily.

Solution? Watchout for ropes/sheets over the side ie SEAMANSHIP!

[Matt Johnson]

Originally Posted by Lagoon4us

Something to consider, the top of a Lagoon's engine room has sound deadened foam glued to a timber flap/door, once the water get's over this level it can flow to the opposite engine room.

Also once it gets to that level it can flow forward under the cockpit floor into the saloon.

The only remedy is in prior action i.e. fit a pump in engine room and seal all potential leaks through the bulkhead.

The water WILL follow the path i described above regardless IF allowed to reach the height.

ONLY a water tight hatch above the engine space (not the deck level but the ply doors above) will make it a 'secure' flooded area and these boats along with most others DO NOT LEND their way to achieving this easily.

Solution? Watchout for ropes/sheets over the side ie SEAMANSHIP!

If water got into the engine bay, would it equalize before it reached the top of the bulkhead? I would imagine that the rest of the hull, without any water in it, would have enough buoyancy to overcome the weight of the water in the engine bay and prevent it from reaching the top of the bulkhead.

[Matt Johnson]

I closed off the area below my v-berth to the rest of the boat creating a waterproof bulkhead. Based on weight, where the water line is, and angle this weight would make us float, this area can be punctured and still keep the boat floating without overflowing this bulkhead. Its like how the Titanic's bulkheads were made...we know how well that worked

[DotDun]

Originally Posted by funjohnson

If water got into the engine bay, would it equalize before it reached the top of the bulkhead? I would imagine that the rest of the hull, without any water in it, would have enough buoyancy to overcome the weight of the water in the engine bay and prevent it from reaching the top of the bulkhead.

That is true. With a solid bulkhead fore and aft of the engine, the small amount of water that would enter probably wouldn't lower the water line more than 1/4". Unless of course the water leak was from a positive source like a ruptured raw water line where the pump kept running until the engine dies.

On my boat, the waterline is about the bottom of the crankcase/top of the oil pan. Hence a hull breach in the engine room would probably not be operationally noticed until one physically checked the space. Of course, I would hope that whatever caused the breach would be noticed at that time raising concern enough to check out everything.

[Palarran]

Originally Posted by Lagoon4us

Something to consider, the top of a Lagoon's engine room has sound deadened foam glued to a timber flap/door, once the water get's over this level it can flow to (the main hull) the opposite engine room.

Also once it gets to that level it can flow forward under the cockpit floor into the saloon.

The only remedy is in prior action i.e. fit a pump in engine room and seal all potential leaks through the bulkhead.

The water WILL follow the path i described above regardless IF allowed to reach the height.

ONLY a water tight hatch above the engine space (not the deck level but the ply doors above) will make it a 'secure' flooded area and these boats along with most others DO NOT LEND their way to achieving this easily.

Solution? Watchout for ropes/sheets over the side ie SEAMANSHIP!

I don't know about all Fountaine Pajot's but mine is the same. That is why in an earlier post I used a max depth of 2'. Above that and there will be a remake of "All is Lost". The max diameter of the holes put through my bulkhead was 2" not 4" so the total pressure would still be negligible. Also, as has been discussed, I have a water tight stern compartment, then the engine compartment, then the main cabin, then the forward v-compartment. If any single one flooded except the main cabin, it would make a very small difference in my buoyancy.

The reason I'm continuing to beat this dead horse is that this Lagoon isn't the only Cat lost due to water flowing from one compartment to another. I think it was a French guy with a newly purchased Lavezzi or Belize who had both hulls flood due to water crossing over through electrical raceways. I remember it because they had a good video of the rescue. If you own a cat, or any boat for that matter, you should pay attention to what's been drilled through your bulkheads.

[djtopper]

I've been following this thread since it popped back up and must say it's chilling. I've also read tons about how unsinkable catamarans are by sheer virtue of the construction material. Makes sense, however, that a fully loaded cruising cat with all the comforts of home might in fact be way too heavy.

Makes me wonder, why don't they put some kind of water alarm in the engine bay? Seems like it would be a simple solution. EG., if the waterline goes above a certain mark, sound the alarm! Seems like it would be better than waiting until you notice one hull sagging.

Granted, it might have been useless in the case this thread is about. I honestly can't believe that an engine compartment isn't water tight though. I mean, it's where the boat quite literally transfers energy and force against the water.

It would be half as bad if the boats only sank when "pierced" as such. Having it happen as a result of the saildrive snapping seems like a dangerous design flaw.