Red wrote:
I hear ya on the flotation!


A lot of people seem to think it isn't practical. It would indeed mean
giving up some interior space, but IMHO many production boats could
have positive flotation installed and give up maybe 15~20% of useable
stowage. A lot of space could be used for flotation that is up in
tight angles & inaccessible spots.

The reason I asked is that I read an article somewhere way back on some
boatbuilding site that kevlar wouldn't bond adequately to old poly
resin.

Can't think why that would be. It's just fancy cloth. More would
depend on the surface prep & type of resin.


.... I'm curious though, why would it be better for the kevlar to be
on the inside? Wouldn't that make it less effective in a collision due
to the layer being in tension so it wants to seperate? I would have
thought that being on the outside would be better to provide a barrier
to the forced entry. Could you explain further? Thanks


I can try. A laminated structure almost always fails in compression...
same as a mast BTW. As force applied increases and the structure
bends, at some point the strength of the bond between layers starts to
fail and the inner face of the bend, the skin that is under
compression, starts to buckle. This is where local tears in the skin
form. After this point failure occurs, the whole thing comes apart
like a zipper until the strain is relieved.

Kevlar is very very strong in tension, and along the tension face or
skin will distribute load over a much wider area than conventional
fiberglass cloth, thus avoiding critical point loading in the opposite
compression face.

OTOH if you're thinking of an object piercing the hull like an ice
pick, having the Kevlar layer on the outside might not make much
difference. In any event, having it on the outside is better than
nothing.

Fresh Breezes- Doug King

OTOH if you're thinking of an object piercing the hull like an ice
pick, having the Kevlar layer on the outside might not make much
difference. In any event, having it on the outside is better than
nothing.

Fresh Breezes- Doug King

------


Actually I was just pondering this as there are frequent stories about
the various partially submerged objects such as shipping containers
sinking boats. Since I am getting closer to buying a boat, I wondered if
there wasn't something that could be done to at least reasonably
increase protection from said objects. I realize you aren't going to
make it bullet proof, but any amount of improvement without too much
tradeoff in weight, etc, may be worth it. Peace of mind sort of thing.
Thanks.

Red

Red wrote:
OTOH if you're thinking of an object piercing the hull like an ice
pick, having the Kevlar layer on the outside might not make much
difference. In any event, having it on the outside is better than
nothing.

Fresh Breezes- Doug King

------


Actually I was just pondering this as there are frequent stories about
the various partially submerged objects such as shipping containers
sinking boats. Since I am getting closer to buying a boat, I wondered if
there wasn't something that could be done to at least reasonably
increase protection from said objects. I realize you aren't going to
make it bullet proof, but any amount of improvement without too much
tradeoff in weight, etc, may be worth it. Peace of mind sort of thing.
Thanks.

Red

Had a friend that put in many, many thousands of miles with at least
7 round trips between New Zealand and Victoria BC.
In that time he hit one container and one sleeping whale. This was in a
homebuilt 33' steel cutter. Both hits in the South Pacific.
The container left a good dent in the bow and the whale bent the rudder.
I guess what I'm trying to say is the chances of hitting something
large enough to cause serious damage is very slight and then probably
wouldn't be catastropic
G

On Tue, 11 Mar 2008 04:43:42 +0000, Gordon wrote:

Red wrote:
OTOH if you're thinking of an object piercing the hull like an ice
pick, having the Kevlar layer on the outside might not make much
difference. In any event, having it on the outside is better than
nothing.

Fresh Breezes- Doug King

------


Actually I was just pondering this as there are frequent stories about
the various partially submerged objects such as shipping containers
sinking boats. Since I am getting closer to buying a boat, I wondered if
there wasn't something that could be done to at least reasonably
increase protection from said objects. I realize you aren't going to
make it bullet proof, but any amount of improvement without too much
tradeoff in weight, etc, may be worth it. Peace of mind sort of thing.
Thanks.

Red

Had a friend that put in many, many thousands of miles with at least
7 round trips between New Zealand and Victoria BC.
In that time he hit one container and one sleeping whale. This was in a
homebuilt 33' steel cutter. Both hits in the South Pacific.
The container left a good dent in the bow and the whale bent the rudder.
I guess what I'm trying to say is the chances of hitting something
large enough to cause serious damage is very slight and then probably
wouldn't be catastropic
G


That is somewhere around 45,000 N.M. so if he hit two objects in that
distance it averages one object every 22,000 miles. How many people
will cruise that distance in their whole life.


Bruce-in-Bangkok
(correct email address for reply)

Gordon wrote:
Had a friend that put in many, many thousands of miles with at least
7 round trips between New Zealand and Victoria BC.
In that time he hit one container and one sleeping whale. This was in a
homebuilt 33' steel cutter. Both hits in the South Pacific.

I wonder what time frame this was? I think shipping losses of
containers is much higher in the late 1990s ~early 2000s although they
say it's tapering off now.

I also wonder what happened to the whale.

The container left a good dent in the bow and the whale bent the rudder.
I guess what I'm trying to say is the chances of hitting something
large enough to cause serious damage is very slight and then probably
wouldn't be catastropic


In a steel boat

Bruce in Bangkok wrote:
That is somewhere around 45,000 N.M. so if he hit two objects in that
distance it averages one object every 22,000 miles. How many people
will cruise that distance in their whole life.


Lots and lots and lots. Not so many do that many open-sea miles. But
look at the odds another way... if you had a revolver with 1,000
chambers, and "only" one chamber had a live round.... would you spin
the chamber, put it to your head, and pull the trigger? Just for fun?

If the odds are low, but consequences very serious, then it's worth a
little work and study to avoid that BANG. Of course, YMMV

DSK

On Tue, 11 Mar 2008 05:55:28 -0700 (PDT), wrote:

Gordon wrote:
Had a friend that put in many, many thousands of miles with at least
7 round trips between New Zealand and Victoria BC.
In that time he hit one container and one sleeping whale. This was in a
homebuilt 33' steel cutter. Both hits in the South Pacific.

I wonder what time frame this was? I think shipping losses of
containers is much higher in the late 1990s ~early 2000s although they
say it's tapering off now.

I also wonder what happened to the whale.

The container left a good dent in the bow and the whale bent the rudder.
I guess what I'm trying to say is the chances of hitting something
large enough to cause serious damage is very slight and then probably
wouldn't be catastropic


In a steel boat

Bruce in Bangkok wrote:
That is somewhere around 45,000 N.M. so if he hit two objects in that
distance it averages one object every 22,000 miles. How many people
will cruise that distance in their whole life.


Lots and lots and lots. Not so many do that many open-sea miles. But
look at the odds another way... if you had a revolver with 1,000
chambers, and "only" one chamber had a live round.... would you spin
the chamber, put it to your head, and pull the trigger? Just for fun?

If the odds are low, but consequences very serious, then it's worth a
little work and study to avoid that BANG. Of course, YMMV

DSK

Without researching it I suspect that the number of boats lost to
hitting floating objects is less then the number of aircraft lost
during the same period. Do you carry a parachute when you fly?





Bruce-in-Bangkok
(correct email address for reply)

wrote:
Gordon wrote:
Had a friend that put in many, many thousands of miles with at least
7 round trips between New Zealand and Victoria BC.
In that time he hit one container and one sleeping whale. This was in a
homebuilt 33' steel cutter. Both hits in the South Pacific.

I wonder what time frame this was? I think shipping losses of
containers is much higher in the late 1990s ~early 2000s although they
say it's tapering off now.

I also wonder what happened to the whale.

The container left a good dent in the bow and the whale bent the rudder.
I guess what I'm trying to say is the chances of hitting something
large enough to cause serious damage is very slight and then probably
wouldn't be catastropic


In a steel boat

Bruce in Bangkok wrote:
That is somewhere around 45,000 N.M. so if he hit two objects in that
distance it averages one object every 22,000 miles. How many people
will cruise that distance in their whole life.


Lots and lots and lots. Not so many do that many open-sea miles. But
look at the odds another way... if you had a revolver with 1,000
chambers, and "only" one chamber had a live round.... would you spin
the chamber, put it to your head, and pull the trigger? Just for fun?

If the odds are low, but consequences very serious, then it's worth a
little work and study to avoid that BANG. Of course, YMMV

DSK



Edward retired in San Diego and built a wood cat and sailed it all
over the S Pac sans engine.
He returned to San Diego, sold the cat and built the cutter.
He went to New Zealand and then to either Pt Angeles Wa or Victoria BC
or even farther north where he would spend the summer or maybe a year.
Edward left NZ last spring in poor health and was reported overdue in
the summer. His boat was finally found washed up on an atoll.
Edward was a very safety oriented person. High welded water pipe for
rails with no gates and sissy bars around the mast.
It is thought Edward probably walked off the stern if he thought his
time had come. He was that type of person.
So you can figure the time frame from this narrative.
Gordon
BTW Edward was 82 years old.

"Bruce in Bangkok" wrote in message
...
That is somewhere around 45,000 N.M. so if he hit two objects in that
distance it averages one object every 22,000 miles. How many people
will cruise that distance in their whole life.


Certainly not you, sir! Pretty hard to get that kind of mileage under your
keel sitting at the Bangkok dock.

Wilbur Hubbard

On Tue, 11 Mar 2008 11:48:14 -0400, "Wilbur Hubbard"
wrote:


"Bruce in Bangkok" wrote in message
.. .
That is somewhere around 45,000 N.M. so if he hit two objects in that
distance it averages one object every 22,000 miles. How many people
will cruise that distance in their whole life.


Certainly not you, sir! Pretty hard to get that kind of mileage under your
keel sitting at the Bangkok dock.

Wilbur Hubbard

And also difficult sitting there with the yellow rubber duck in the
bathtub.

Bruce-in-Bangkok
(correct email address for reply)

On Mon, 10 Mar 2008 22:27:50 -0500, Red wrote:

OTOH if you're thinking of an object piercing the hull like an ice
pick, having the Kevlar layer on the outside might not make much
difference. In any event, having it on the outside is better than
nothing.

Fresh Breezes- Doug King

------


Actually I was just pondering this as there are frequent stories about
the various partially submerged objects such as shipping containers
sinking boats. Since I am getting closer to buying a boat, I wondered if
there wasn't something that could be done to at least reasonably
increase protection from said objects. I realize you aren't going to
make it bullet proof, but any amount of improvement without too much
tradeoff in weight, etc, may be worth it. Peace of mind sort of thing.
Thanks.

Red

Perhaps the first thing wold be to research the subject to determine
how many fiberglass/steel/aluminum/wooden yachts are sunk annually.
Once the frequency is determined it should be easy to assess the
appropriate action.

as an example, airplanes crash nearly every year but few passengers
carry a parachute as part of their carry-on luggage...


Bruce-in-Bangkok
(correct email address for reply)