Dumping keel and mast to make boat "unsinkable"

[Wellydeckhand]

Originally Posted by SeaSpark

The keel box for the lifting keel will provide a "well" so water can't enter the boat.

I have been looking in to airbag like systems, the material of the bag will have to be very strong so it will not get punctured when it meets something sharp when beeing blown up.

As an alternative i have been thinking about a thin bag that fills with a 2 component foam. You need quite a large amount of foam for this and i wonder if it will cure fast enough. You would be able to carve out the foam to reach supplies needed for survival.

Kelvar Airbag..............................

WDH

[solrac]

mmmm... have anyone seen the National Geographics videos of "re-floating" some sinked ships? they use some kind of inflatable really big "bags"
Don't think it would be so difficult to find.
alas, the inflatable poles used for regatta signalization?
the kind of zodiac inflatable boats material?
even a couple rubber truck tires can do the job, lets check:
a standard truck tire camera 760/14 full inflated @ 1 bar holds about 1.10 / 1.20m3, at 5 bar it holds about 2.5m3 (do not try this, apart from risk of exploding, the external pressure force of about 5kg/cm2 may harm a lot of your cabin) you wouldn't need more than 4.... (just tell me, haven't you ever played at beach or river when you were a kid with one of this?)

[DanishBagger]

What about mylar? That is what they use for wine-bags amongst other things as far as I know.

[solrac]

Originally Posted by DanishBagger

What about mylar? That is what they use for wine-bags amongst other things as far as I know.

filling it with wine? not bad.... thought it has a 0.88 density respect water, can be a lot of fun, but don't think it will help as floating device...

[yokebutt]

Once upon a time, there was a Danish engineer who raised a sunken ship by blowing in styrofoam beads. Unfortunately, he was denied a patent because he got the idea from an old Donald Duck comic magazine.

Yoke.

[DanishBagger]

Originally Posted by solrac

filling it with wine? not bad.... thought it has a 0.88 density respect water, can be a lot of fun, but don't think it will help as floating device...

Hehe, I thought I'd put it there, because if it can hold an acidic fluid, it must be pretty tough

[SamSam]

Originally Posted by SeaSpark

While thinking about safety i came up with the following idea:

A wood epoxy hull with foam sandwich interior and deck is very light and will float when holed (or even split in two) by for example a collision. If it were not for weight of the keel. My design has a lifting keel so it is easy to dump. To keep some sort of stability the mast will also have to go. It has no stays so is easy to dump also. Then the idea came to dump the mast using the weight of the keel, see illustration. The weight of engine, water and fuel tanks have to provide stabilily in this condition.
Any comments welcome.

SeaSpark,
The following is a quote...

"On boats, it has been well proven that the very distribution of weights athwartships and into the rig are in fact favorable to stability in a 'dynamic' environment. We have observed that boats that have been dismasted are much more likely to be rolled over. This is due to the lack of inertia (lesser roll moment of inertia) and the relative ease with which a heavy roll can be suddenly induced. This cannot be demonstrated by static analysis as one would normally expect, since the dismasted boat obviously has 'more' static stability without a mast - in the actual ocean though, it is the opposite."

from this page about a third of the way down under 'ROLL MOMENT'
http://www.kastenmarine.com/beam_vs_ballast.htm
The site was posted by someone in another thread. The guy seems to know a few things and according to this it would seem you might be accomplishing the exact opposite of what you want as far as safety. Sam

[SeaSpark]

The guy seems to know a few things and according to this it would seem you might be accomplishing the exact opposite of what you want as far as safety.

This guy should also know it is more safe to stay on your boat for as long as possible before stepping in your liferaft.

[Omeron]

SeaSpark, i love novel ideas as yours, it lubricates the brain cells and practices mind. But since you are taking all this trouble to save yourself
in a rather unlikely occurance, i would think that you would test it a few times to make sure it works.
I am just curious, how many times would you eject your mast and drop your keel, to make sure it works ok!
Ofcourse doing this on a sunny summer day, on flat water is one thing, and trying it in the dark of the night, with breaking seas, and water rushing in is another.

[TeddyDiver]

Didn't read the whole thread throw, and so don't know if this has been mentioned before.
Had a thought about your idea, and In think distributing the ballast partly, from 50/50 to 70/30, btw hull (or long keel) and lifting keel would give you the chance to keep your mast.

[SeaSpark]

think distributing the ballast partly, from 50/50 to 70/30, btw hull (or long keel) and lifting keel would give you the chance to keep your mast.

Very good idea, with a weighted centerboard/long keel configuration like this it should be possible:



My initial plan was to have a boat that could go faster than the speed determined by its waterline length with added headsails in fully crewed conditions. This is not possible with the hull shape shown above.

I can have impractical ideas.

[Brent Swain]

Check the photo on steel boat construction. Looks like a much simpler solution. Build in steel and forget about it.
Brent

[SeaSpark]

Guess who posted the picture:

Steel yacht construction

At the moment i am thinking steel yacht with a fast sailing proa for dinghy to satisfy my need for speed. A single long narrow hull should be able find a place on the front deck of a 50ft yacht. The "outrigger hull" can fit in the main one.

If budget was not a concern i would fully investigate any other option, ehhh..... i am doing that anyway.

[SeaSpark]

http://kitefilm.com/video/canoetrailer_256.wmv