500: Lagoon 500 Nearly Sunk

[D&D]

At the risk of serious thread drift () this is just a courtesy 'heads up' that there are only a few days left in our CF October Giveaway thread (http://www.cruisersforum.com/forums/...ml#post1374774 ). Given that we (and all of our products) are for cat cruising, we suspect there may be a few (if not most!) of those on this thread who might find some items of interest, especially as potential 'freebies'...

Now back to the nearly sinking L500...

[Lagoon4us]

It may be of interest to some, i just did a volume calculation of the two bow and the two stern (engine room) void spaces on my LAGOON 440.

The total free space in them is as near as dammit 500 cubic feet.

Now 500 cubic feet gives you around 14 tonne of buoyancy.

A LAGOON 440 in cruising trim weighs in just under 13 tonne.

Provided you can keep the water out of those end spaces it will not sink.

Even with one space voided it will not sink as the 13 tonne comprises of a lot of lighter than water materials i.e. wood Which will give some buoyancy.

I feel a 50 foot LAGOON would calculate similarly.

Cheers Frank

[BigBoater917]

Originally Posted by Lagoon4us

It may be of interest to some, i just did a volume calculation of the two bow and the two stern (engine room) void spaces on my LAGOON 440.

The total free space in them is as near as dammit 500 cubic feet.

Now 500 cubic feet gives you around 14 tonne of buoyancy.

A LAGOON 440 in cruising trim weighs in just under 13 tonne.

Provided you can keep the water out of those end spaces it will not sink.

Even with one space voided it will not sink as the 13 tonne comprises of a lot of lighter than water materials i.e. wood Which will give some buoyancy.

I feel a 50 foot LAGOON would calculate similarly.

Cheers Frank

14 tons isn't much. 1 cubic meter of saltwater is a ton so 500 ft^3 offers ample space for more than enough water to overcome your buoyancy.

[Lagoon4us]

Originally Posted by BigBoater917

14 tons isn't much. 1 cubic meter of saltwater is a ton so 500 ft^3 offers ample space for more than enough water to overcome your buoyancy.

Without being pedantic about salinity or US weights and measures etc I'll try to make my point clearer.

The hull of a Lagoon 440 cannot sink provided that the four watertight compartments are just that....WATERTIGHT. Simply because those compartments can alone prevent a sinking.

There is more than enough extra buoyancy in the 600 litre water tanks if emptied immediately along with the timber fit-out and other 'trapped air'.

Cheers

[raphaella]

I totally agree with Capt. Bill. Had a cruiser once and realized that the whole .... thing was flooded with water only when we started the motor and heard a water fall instead of the motor, opened the hatch and ouch what a nightmare, thought we would sink but guess what it floated. Never thought the thing would stay afloat with all that water in it!!!

[Lagoon4us]

To have a boat flooded with water is an indescribable horror story, the surge as the boat rocks around, caused by the wave action outside, is totally destructive, now when we say FLOAT it's because the inherent bouyancy is larger than the boats actual weight it means it will float with some cabin sticking out. This is if the centre/keel sections are compromised.

Once the water is in the boat the waters weight is non-existent in the scheme of things unless you try to lift it because it's the bouyancy that you've lost, because it's likely the water will have transferred to the other side.

This thread is about whether the boat will sink and the calc's i've done say provided you don't compromise the 4 compartments it won't sink, with one of them gone as was this case you will still float PROVIDED the bulkheads are still watertight preventing the water from moving amidships.

We put valves on the lowest part of the bulkheads when we bought the boat.

Cheers

[neilpride]

Bulkheads atached with just plexus around, cracks around the plexus, no glass, poor fiberglass layup around joints and corners, good luck try to make it unsinkable....

[minaret]

Originally Posted by Lagoon4us

Why you people believe Catamarans are unsinkable confounds me, are you stupid or just pretending to be?

Being unsinkable is a requirement of a dinghy full of flotation for survey purposes, compartmentalisation to reduce risk is a survey requirement also to reduce risk.

Stupidty is hard to design around as is bad seamanship, monohull/trimaran/catamaran it matters not, put a big enough hole in it and it's going down, the secret is not to do that in the first place... SheeeesssssssshhhHHHHH!

Nice 180* from this post! Went from "why you people think catamarans are unsinkable confounds me" to "my catamaran is unsinkable" in one page!

[Lagoon4us]

The end bulkheads are totally glassed to the hull standard by Lagoon, what you are referring to is the floors they are bonded with a gumbo.
Luck is not needed.

Cheers

[Lagoon4us]

They are not unsinkable, if you read the post i bothered to measure the volumes instead of waffling on like some do.

If you bother to read my post i said it depends where the damage is.

You of all people should understand how a hull is compartmentalised HOWEVER Lagoon don't watertight there bulkheads they allow the water to flow through a 1 inch hole at the bilge apex. You need to put a valve their or block that hole to get integrity.

Cheers

[minaret]

Originally Posted by Lagoon4us

It may be of interest to some, i just did a volume calculation of the two bow and the two stern (engine room) void spaces on my LAGOON 440.

The total free space in them is as near as dammit 500 cubic feet.

Now 500 cubic feet gives you around 14 tonne of buoyancy.

A LAGOON 440 in cruising trim weighs in just under 13 tonne.

Provided you can keep the water out of those end spaces it will not sink.

Even with one space voided it will not sink as the 13 tonne comprises of a lot of lighter than water materials i.e. wood Which will give some buoyancy.

I feel a 50 foot LAGOON would calculate similarly.

Cheers Frank

Are you a naval architect? No? Lets leave the buoyancy calcs to those who are. You're "feeling" about the calcs of the boat in question are not relevant data.

[Lagoon4us]

And you are not relevant, my qualifications suffice for me to do a bouyancy calc.

[minaret]

Originally Posted by Lagoon4us

And you are not relevant, my qualifications suffice for me to do a bouyancy calc.

Your qualification suffice for you to determine the buoyancy of a boat by taking measurements on a different boat!? What kind of qualifications are those, super mans school of naval architecture? I gotta get me one of those diplomas!

[Lagoon4us]

Did you read what i said or are you sniffing thinners? A bouyancy calculation is the most simple calc you can do, i.e. weight of vessel from the Architects schedule in wet trim and a simple void space calculation ie VOLUME.

I'm acreddited as a Shipbuilder under the AMSA requirements using the USL Code.

I'm presently sitting in our 440, a Lagoon 50 is 6 feet bigger ie 50-44=6. You still follow?

As i said i suspect the 50 is constructed in very similar fashion.

Another point for you to ponder between sniffs, it may not be coincidental that the free volume of the watertight (almost but for a dumb limber hole) compartments at the ends of a Lagoon 440 (in this instance) just happens to match the wet weight of the boat????

Instead of shooting at a contributer to a thread that bothers to do a volume check on a similar boat maybe you should consider what is being said.

Cheers

[minaret]

Originally Posted by Lagoon4us

Did you read what i said or are you sniffing thinners? A bouyancy calculation is the most simple calc you can do, i.e. weight of vessel from the Architects schedule in wet trim and a simple void space calculation ie VOLUME.

I'm acreddited as a Shipbuilder under the AMSA requirements using the USL Code.

I'm presently sitting in our 440, a Lagoon 50 is 6 feet bigger ie 50-44=6. You still follow?

As i said i suspect the 50 is constructed in very similar fashion.

Another point for you to ponder between sniffs, it may not be coincidental that the free volume of the watertight (almost but for a dumb limber hole) compartments at the ends of a Lagoon 440 (in this instance) just happens to match the wet weight of the boat????

Instead of shooting at a contributer to a thread that bothers to do a volume check on a similar boat maybe you should consider what is being said.

Cheers

Well as long as you suspect the 50 is the same as your 440, that's good enough for me! We'll just assume everything posted earlier was a lie based on that. That 500 couldn't have sunk! Because of the calcs on your 440, obviously...