Hello

I'm an armchair cruiser, daysailer, epoxy salesman and
thinker...

I've been reading a book about 40 or 50 'yachts lost at
sea' stories. Interesting reading. Made me start to
think...

Seems to me that watertight bulkheads forward of the mast,
aft of the forward cockpit, and watertight floorboards
(lots of stories of water rising up thru the floorboards)
would be life/boat saving design elements. Also, engine
and batteries in water tight compartments vented to the
deck (always - rising water kills the engine and or
electric pumps/radio).

Maybe even a watertight companionway hatch so that the
entire main cabin could become a giant air chamber....

If not watertight bulkheads, how about inflatable airbags
in the cabin to keep the hull afloat?

On more unconventional design considerations - bilge keels
would have keep many of the boats I read about from
pounding their topsides to death on reefs or beaches. I
know bilge keels have there faults (I've read about
everything I could find on bilge keel cruisers) but a boat
that reduces draft when not heeled over and sits upright
could be a real life saver.

Even more radical might be a A frame type mast (ie. sold
shrouds, no center mast) would keep the rigging in place
after a roll-over/broach much better then a stick with
wire rigging.


Anyway, I'm surprised more offshore boats aren't resigned
or retro-fitted for max survival. As I read this book it
made me realize these aren't just boats, often they are a
couple's home for decades (and lost in minutes). Surely a
few watertight bulkheads and watertight/airtight hatches,
while probably a pain to deal with on a day to day basis,
could keep you alive and your home/boat afloat.

Comments anyone?


Paul Oman
progressive epoxy polymers


"Living on Earth is expensive, but it does include
a free trip around the Sun every year."

Many modern catamarans incorporate these features already.

Paul Oman wrote:

Seems to me that watertight bulkheads forward of the mast,
aft of the forward cockpit, and watertight floorboards
(lots of stories of water rising up thru the floorboards)
would be life/boat saving design elements.

Most cats have collision bulkheads forward. Mine has 4 watertight
compartments forward, and two aft. Also, with no keel and foam
construction, its virtually unsinkable.


Also, engine
and batteries in water tight compartments vented to the
deck (always - rising water kills the engine and or
electric pumps/radio).

Many cats have this - and with two engines the odds are further improved.



Maybe even a watertight companionway hatch so that the
entire main cabin could become a giant air chamber....


A bit problematical ... a singlehander might want to seal himself in for
the southern ocean, but most folks want easy access to deck.



If not watertight bulkheads, how about inflatable airbags
in the cabin to keep the hull afloat?

This can be done for some boats, but ocean cruisers often chose very
heavy boats, making this difficult to implement. A 6000 pound keel
requires about 100 cubic feet of flotation - that's a 5 foot cube for a
fairly modest boat!



On more unconventional design considerations - bilge keels
would have keep many of the boats I read about from
pounding their topsides to death on reefs or beaches. I
know bilge keels have there faults (I've read about
everything I could find on bilge keel cruisers) but a boat
that reduces draft when not heeled over and sits upright
could be a real life saver.

Again, cats incorporate bilge keels. Many cats have "sacrificial keels"
and will "reduce their draft" from 3 feet to 2 automatically when
passing over a reef!



Even more radical might be a A frame type mast (ie. sold
shrouds, no center mast) would keep the rigging in place
after a roll-over/broach much better then a stick with
wire rigging.

I'm curious - is there any evidence for this?



Anyway, I'm surprised more offshore boats aren't resigned
or retro-fitted for max survival. As I read this book it
made me realize these aren't just boats, often they are a
couple's home for decades (and lost in minutes). Surely a
few watertight bulkheads and watertight/airtight hatches,
while probably a pain to deal with on a day to day basis,
could keep you alive and your home/boat afloat.

Some of the modern cruisers have some of these features. And the long
distance racers have many of them. But, a large number of world
cruisers are using boats built 30 years ago. Most new boats never leave
protected waters, and even the ambitious cruisers usually are actually
island hopping. Statistically, there's a rather small market for this.

"Jeff Morris" wrote in message
...
Many modern catamarans incorporate these features already.

Paul Oman wrote:

Seems to me that watertight bulkheads forward of the mast,
aft of the forward cockpit, and watertight floorboards
(lots of stories of water rising up thru the floorboards)
would be life/boat saving design elements.

Most cats have collision bulkheads forward. Mine has 4 watertight
compartments forward, and two aft. Also, with no keel and foam
construction, its virtually unsinkable.


Also, engine
and batteries in water tight compartments vented to the
deck (always - rising water kills the engine and or
electric pumps/radio).

Many cats have this - and with two engines the odds are further improved.



Maybe even a watertight companionway hatch so that the
entire main cabin could become a giant air chamber....


A bit problematical ... a singlehander might want to seal himself in for
the southern ocean, but most folks want easy access to deck.



If not watertight bulkheads, how about inflatable airbags
in the cabin to keep the hull afloat?

This can be done for some boats, but ocean cruisers often chose very heavy
boats, making this difficult to implement. A 6000 pound keel requires
about 100 cubic feet of flotation - that's a 5 foot cube for a fairly
modest boat!



On more unconventional design considerations - bilge keels
would have keep many of the boats I read about from
pounding their topsides to death on reefs or beaches. I
know bilge keels have there faults (I've read about
everything I could find on bilge keel cruisers) but a boat
that reduces draft when not heeled over and sits upright
could be a real life saver.

Again, cats incorporate bilge keels. Many cats have "sacrificial keels"
and will "reduce their draft" from 3 feet to 2 automatically when passing
over a reef!



Even more radical might be a A frame type mast (ie. sold
shrouds, no center mast) would keep the rigging in place
after a roll-over/broach much better then a stick with
wire rigging.

I'm curious - is there any evidence for this?



Anyway, I'm surprised more offshore boats aren't resigned
or retro-fitted for max survival. As I read this book it
made me realize these aren't just boats, often they are a
couple's home for decades (and lost in minutes). Surely a
few watertight bulkheads and watertight/airtight hatches,
while probably a pain to deal with on a day to day basis,
could keep you alive and your home/boat afloat.

Some of the modern cruisers have some of these features. And the long
distance racers have many of them. But, a large number of world cruisers
are using boats built 30 years ago. Most new boats never leave protected
waters, and even the ambitious cruisers usually are actually island
hopping. Statistically, there's a rather small market for this.

First off the sea can and will, on occasion, destroy anything made by man.
So you always need to understand that you can only increase the probability
of survival...you cannot guarantee it. So this all is a game of
statistics...how may dollars are you willing to pay to double the
probability of surviving the next storm you hit? Remember that your
survival is a pretty good bet to start...Maybe 99.5% or more for a
reasonably equipped fibreglass boat conseratively operated. So how many
dollars would you pay to go from 99.5% to 99.75%?

In a bad sea people abandon boats that survive. Many of the existing boats
can easily survive a knockdown or even a roll...though with some damage.
But if caught in a really bad storm that lasts for any significant time
survival becomes difficult whether the boat sinks or not. Life inside a
washing machine is difficult.

Hitting a bad reef is not likely to be survived by bilge keels. Once hung
you best get off quickly or the boat is gone. A reef simply grinds the
bilge keel off. On the other hand a bilge keel is not going to be nearly as
good keeping the top side up as a conventional keel. Bilge keels certainly
have their place in drying harbors and thin water but don't really have
much charm when in the deep blue sea.

Practically you need not be water tight to survive a roll. Normal boat
structures will take some water but not enough to sink them in a roll. You
can set them up so engine and batteries survive most anything. Water tight
is probably overkill.

Water killing the engine generally indicates a bad hole. Sometimes you can
get a huge amout of water into a boat by a simple plumbing failure. In any
case a rip in the hull can still get the engine compartment or some other
required system. You are in big trouble if your fuel tank vents are under
water or your main electrical panel goes.

Jim Donohue

Also, engine
and batteries in water tight compartments vented to the
deck (always - rising water kills the engine and or
electric pumps/radio).

Batteries should ideally be in watertight boxes but should also drain
(in case of charging gas escaping) to prevent danger of explosion. So
this is paradoxical to start with. And second, if the engine is not
sealed off, you can divert the raw water intake to pump out incoming
water in the engine compartment. This can off course also be done with
other means but an engine sure is a powerful and reliable pump!
As long as you make sure electrical boards are higher than the engine's
air intake, both will continue working untill it's really too late. But
by that time buoancy will be so diminished, you won't be using power or
engine anymore.

And always remember: the best means of getting water out is a scared
person with a bucket :-)

Victor (currently installing the 4th pump in the bilge - 1 engine, 2
electrical, 1 manual)

"Paul Oman" wrote in message
...
Hello

I'm an armchair cruiser, daysailer, epoxy salesman and
thinker...

Seems to me that watertight bulkheads forward of the mast,
aft of the forward cockpit, and watertight floorboards
(lots of stories of water rising up thru the floorboards)
would be life/boat saving design elements.

I think this would make most boats a lot safer, and it's really
not that hard to do. I'm not so sure about the floorboards -
they'd probably have to be about as stout as the bottom of the
hull, and most people like to use the space for storage. My
thoughts are that if you have the watertight subdivision you should
be in good enough shape to not need the floorboard seals.

The nice thing about subdividing the way you describe is
it keeps the boat from getting too far out of trim, even if
one compartment is full. Titanic rips along the hull side and
across two compartments might be a problem though.

Also, engine
and batteries in water tight compartments vented to the
deck (always - rising water kills the engine and or
electric pumps/radio).

Why not make the engine compartment watertight so
you didn't have to worry about rising water? A side
benefit is that it will be more soundproof as well. Also,
a lot of diesels will keep running without electricity.
Batteries ought to be gel type, just to eliminate the
possibility of a sulphuric acid spill which can make
belowdecks uninhabitable.

If not watertight bulkheads, how about inflatable airbags
in the cabin to keep the hull afloat?

There actually used to e a product like this - but the
company went out of business. One rumor I heard
is that the company got sued because the airbags
weren't tied to the hull, but rested against the bottom
of the deck when inflated. The hull/deck joint typically
doesn't have the strength to take this additional load,
and the boat sank.

One of the other posts suggested using the engine raw
water pump as additional dewatering capacity. Good
in theory, but the reality is they only pump three or four
gallons a minute. Better to get something like an Ericson
safety pump that throws maybe 750 gallons a minute.
That'll keep up with most holes.
http://bestmarineimports.com/ERICSON.html

So that leaves us with the other major thing that
can ruin your sailing day - fire. Paul, you're the
resin guy, what can we do to keep the galley fire
from turning the resin into a runaway ball of orange
flame and black choking smoke?

"Paul Oman" wrote in message
...
Hello

I'm an armchair cruiser, daysailer, epoxy salesman and
thinker...

I've been reading a book about 40 or 50 'yachts lost at
sea' stories. Interesting reading. Made me start to
think...

I love these kinds of books. If you have not read John Rousmaniere's books
on the subject I highly reccomend them.

Seems to me that watertight bulkheads forward of the mast,
aft of the forward cockpit, and watertight floorboards
(lots of stories of water rising up thru the floorboards)

Remember that water almost always appears to rise through the floorboards
because it goes to the bottom of the boat first. So if your leak is through
the side of the hull behind a cabinet or storage space the water will go
down the side of the hull (inside) and then "rise up through the floor
boards."

would be life/boat saving design elements. Also, engine
and batteries in water tight compartments vented to the
deck (always - rising water kills the engine and or
electric pumps/radio).

In addition to bulkheads you could have a double bottom, but in each case
you are adding cost to the boat, increasing wieght and decreasing comfort.
For a smaller crusing boat these penalties can become quite serious.

Maybe even a watertight companionway hatch so that the
entire main cabin could become a giant air chamber....

If not watertight bulkheads, how about inflatable airbags
in the cabin to keep the hull afloat?

On more unconventional design considerations - bilge keels
would have keep many of the boats I read about from
pounding their topsides to death on reefs or beaches. I
know bilge keels have there faults (I've read about
everything I could find on bilge keel cruisers) but a boat
that reduces draft when not heeled over and sits upright
could be a real life saver.

Even more radical might be a A frame type mast (ie. sold
shrouds, no center mast) would keep the rigging in place
after a roll-over/broach much better then a stick with
wire rigging.


Anyway, I'm surprised more offshore boats aren't resigned
or retro-fitted for max survival.

I'm not, because the purpose of going sailing is not simply survival, its
all sorts of things. Obviously going sailing in a boat that will never
survive makes no sense, but (because of design tradeoffs) going in a boat
that will always survive makes no sense either. Ever taken a good look at
the escape pod type lifeboats that are carried on the backs of some ships
and North Sea oil rigs? They will survive anything but who would want to go
cruising in one? It would be a nightmare of discomfort.


As I read this book it
made me realize these aren't just boats, often they are a
couple's home for decades (and lost in minutes).

So is my house and it has a number of defects that make it vunerable to fire
(for example its wood, and its full of furniture that burns, stoves that use
gas and so on) and its got no earthquake protection at all.

Surely a
few watertight bulkheads and watertight/airtight hatches,
while probably a pain to deal with on a day to day basis,
could keep you alive and your home/boat afloat.

Comments anyone?

As you can guess survival is not the only issue, like everything else in
life its all trade offs. If I lived in a cinderblock house with concrete
furniture it would never burn down, not ever. But I make my trade off of
fire risk in exchange for comfort just like everyone else.


Paul Oman
progressive epoxy polymers


"Living on Earth is expensive, but it does include
a free trip around the Sun every year."