Sailing Visitors Blown Away By Help

[Seaslug Caravan]

Is this level of Flotation acceptable in a modern cruising catamaran.



See...https://www.news-mail.com.au/news/sa...-help/3266181/

[ozsailer]

OK Seaslug, question - what is the actual damage before you go posting this type of thread. Also what is the level of designed flotation for this vessel (Lagoon 440) Is it a small hole, several holes, is the whole underside of one or more of the pontoons gone. One cannot make an assessment of your question without a lot more factual evidence. What other factual evidence can you supply. Are we prepared to ask the same question of a modern mono or for that matter any boat. .


Greg H
Lake Macquarie

[Wotname]

Originally Posted by catsketcher

Let's say she weighs 10 tonnes so we need 5 cubic metres of well sealed voids in each hull to stop her sinking. That is going to be hard to do for most people to accept - a 44 gallon is only 200 litres - so you need the equivalent of 25 in each hull, down lowish to get it to float at say 2 feet down on lines. A little void fore and aft won't really cut it. Easier to carry a liferaft or big RIB.
.........
Phil

I think you have forgotten to consider the effect of the specific gravity of the hull's principle material...

[Ozbullwinkle]

Oh Seaslug here we go again, it's a never ending vendetta! [emoji42][emoji42][emoji42]

[Sailmonkey]

So you want a boat filled with foam or empty tanks?

What do you hope to accomplish with these posts?

[Factor]

I love the royal "we" as if the OP speaks on behalf of all multi sailors, builders, and owners despite being none of the former.

[Tetepare]

Actually, it's a good question.

Aside from Amel (if I'm correct), monohulls have no effective floatation mechanism.

I don't know why cats seem to need floatation and monohulls don't, but I can believe from design that cats may be easier to keep floating.

Of course, space is the big issue. I'm sure I'm not the first to suggest it, but why not deflated bags attached to scuba tanks?

[transmitterdan]

Flotation is a crew safety feature. It seems in this case it saved the crew so what's not to like about it. It's a boat not a submarine.

[smj]

Originally Posted by Seaslug Caravan

Is this level of Flotation acceptable in a modern cruising catamaran.







See...https://www.news-mail.com.au/news/sa...-help/3266181/

Yes,,

[Pete7]

I have changed the title to reflect the subject of the thread, ie the hospitality shown to someone less fortunate than themselves.

Pete

[Matt Johnson]

Originally Posted by Tetepare

Actually, it's a good question.

Aside from Amel (if I'm correct), monohulls have no effective floatation mechanism.

I don't know why cats seem to need floatation and monohulls don't, but I can believe from design that cats may be easier to keep floating.

Of course, space is the big issue. I'm sure I'm not the first to suggest it, but why not deflated bags attached to scuba tanks?

Etap is the only company I know that built boats using flotation foam in their hulls. The watertight bulkheads of the Amel and others will keep the boat from sinking if you hole the ends, but not if the main cabin gets holed.

Matt

[sailjumanji]

Originally Posted by Ozbullwinkle

Oh Seaslug here we go again, it's a never ending vendetta! [emoji42][emoji42][emoji42]

Yep. If I see a post with pic of a partially submerged cat, you know it's from sluggo. So what's the story. Crew left him for a cat? Don't feel bad, it happens a lot!

[CatNewBee]

Well after all it floats - doesn't it? I am so sorry for them. Hope they can fix it soon and continue their journey.

[David M]

Reminds me of Intel vs AMD or Ford vs Chevy. It never ends and it is immature.

[catsketcher]

Originally Posted by Wotname

I think you have forgotten to consider the effect of the specific gravity of the hull's principle material...

It is interesting to calculate the effect of foam core on a submerged cat. Let's make a few assumptions. Foam weighs nothing. Distance from keel to gunwale - average 2.5m. LOA 12.0m, foam thickness 0.012m. Volume = 2.5x12x0.012 = 0.36 m^3. Multiply by 4 and we get 1.44 m^3. Add in a bit for a bridgedeck floor and you get some reasonable flotation, say enough to float 2 tonnes. For this boat we have 8 tonnes deficit so she sinks very low. I have only calculated flotation till the gunwale goes under but the cabin and interior should provide more flotation.

I don't want to come across as a Polyanna about this thread but cats that don't float well after catastrophic failure are pretty new to the cruising cat arena. The thought used to be that a cat with its bottom ripped out would usually float high enough to provide safety for the crew. So for some lighter, thicker core cats this is probably still the case. Hence why many cats don't have a liferaft, but it seems that the heavier cats don't provide enough flotation to keep the crew safe when the hull is ruptured. So a raft would be an important consideration for these cats. There have been more than a few racing cats that have had large holes made during racing that have gotten themselves home - XL2 once got T boned with a large hole, and they made it to a beach under their own steam.

I like learning more about the boats we sail but maybe there could be a private thread where we could discuss these things without causing owners of sisterships to feel annoyed.

cheers

Phil