Any opinions out there on the use of coring on a power boat hull? balsa or
foam ? I am looking at purchasing a 33 ft Carver that has a baltec cored
hull , the boat is mint but I am concerned about this type of construction.
Any advise or stories appreciated.....

Get a moisture meter. Worth every penny.


"gltlwlelilslslsl" wrote in message
news:I2cTb.363845$X%5.110854@pd7tw2no...
Any opinions out there on the use of coring on a power boat hull? balsa
or
foam ? I am looking at purchasing a 33 ft Carver that has a baltec cored
hull , the boat is mint but I am concerned about this type of
construction.
Any advise or stories appreciated.....

i don't have an opinion, but the guy at
http://www.yachtsurvey.com/structuralissues.htm does.

i'm sure others have other opinions.

hugh


"gltlwlelilslslsl" wrote in message
news:I2cTb.363845$X%5.110854@pd7tw2no...
Any opinions out there on the use of coring on a power boat hull? balsa
or
foam ? I am looking at purchasing a 33 ft Carver that has a baltec cored
hull , the boat is mint but I am concerned about this type of
construction.
Any advise or stories appreciated.....

"gltlwlelilslslsl" writes:

Any opinions out there on the use of coring on a power boat hull?
snip

Airex yes, anything else, especially balsa. forget it.

--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: http://home.earthlink.net/~lewhodgett for Pictures

Lets compare the foams with balsa at equivalent densities. Boat builders may
use balsa at 8-12lb per cubic foot density while they use foams at aound 5-6 lb
density. If the builders used the same density foam as balsa, it would be no
contest, such foams as PVC would win hands down as they would be more than
twice as strong as what is normally used by boat builders, as it has a leg up
in being much tougher.

My sevs use 4.5 lb urethane foam, fragile, for the homebuilders, but certainly
very workable. While a planing boat is trying to break itself in half at the
spray root when it pitty pats along or hits a bump, the surface skimmer
actually sees a mellow down load on the center of the hull as the bump forces
are delivered through the air cushion to the entire underside of the craft.

I also use 5.5 lb PVC, much stronger. The fiberglass skinned foam is ideal for
surface skimmers, especially when considering they don't have to live in the
water, but need to haul themselves out, a necessity to avoid marine growth on
the hull and skirt.

Why the boat builders do not seem to use higher density foams, in the area of
balsa, I do not know. A web site this thread directed me to was very
interesting, but the surveyor who wrote it failed to realize that "composite"
structures are not loaded so that "peel" forces are exerted if they are
properly designed.



Subject: cored hulls
From: "Lew Hodgett"
Date: Mon, Feb 2, 2004 4:29 PM
Message-id: . net


"gltlwlelilslslsl" writes:

Any opinions out there on the use of coring on a power boat hull?
snip

Airex yes, anything else, especially balsa. forget it.

--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: http://home.earthlink.net/~lewhodgett for Pictures

BRBR

Barry Palmer, for A
HREF="http://members.aol.com/sevtec/sev/skmr.html"Sevtec/A

Look carefully at the construction. There is a world of difference in
how the cores are used. I am no fan of balsa. Won't use it anymore,
but in some cases it is adequate.
Hard to beat an experienced surveyor when buying a used boat.

I would say that there is some truth to all of the above comments,
however there seems to be one fact missing here. When building a
cored boat one has to use construction methods that are appropriate
for this type of laminate schedule. If you look at core failures, be
it delamination or water absorbtion, the most common link is poor
construction quality and misapplied use of the technology. There is
nothing wrong with Balsa, Airex, Core Cell, Divinicell, Nomex etc, so
long as the designers and builders are careful to use thes
technologies properly. Not coring in way of the keel or heavily
loaded deck structures is one good, easy to spot for the average
consumer, misuse of cores. Make sure that the cored hull was AT LEAST
vacum bagged. DO NOT purchase a cored hull that was laid up by hand
without vacum bagging, plain and simple. These days Scrimp and other
resin infusion technologies make trusting a cored hull far easier.
The structural/weight advantages of using a cored hull are quite
dramatic, so one should not be scared into thinking that they are
unreliable...this is quie simply false. The comment about about
hiring a good surveyor is right on. Even then though, keeping what I
have said in mind can go a long way despite having a surveyor....the
vacum bagging for example. Even if the surveyor finds the hull
essentially sound, I would err on the side of safety and insist that
the hull you purchase was vacum bagged or resin-infused. Certainly
these days a surveyor can go a lot further with non-invasive laminate
testing, but ultimately the one buying the bboat should educate
him/herself as much as possible. Also, the moisture meter comment is
right on too. These are relatively inexpensive and easy to use. One
caveat, make sure the boat you are testing has been out of the water
for some time before you go sticking the meter into the hull. You'll
get misleading results if you try using it on a boat that has just
been pulled from the water (I've seen unscrupulous brokers/ yard
people trying to lure potential buyers of one boat to antother using
this technique).
-Eli





(hankh) wrote in message . com...
Look carefully at the construction. There is a world of difference in
how the cores are used. I am no fan of balsa. Won't use it anymore,
but in some cases it is adequate.
Hard to beat an experienced surveyor when buying a used boat.

I would say that there is some truth to all of the above comments,
however there seems to be one fact missing here. When building a
cored boat one has to use construction methods that are appropriate
for this type of laminate schedule. If you look at core failures, be
it delamination or water absorbtion, the most common link is poor
construction quality and misapplied use of the technology. There is
nothing wrong with Balsa, Airex, Core Cell, Divinicell, Nomex etc, so
long as the designers and builders are careful to use thes
technologies properly. Not coring in way of the keel or heavily
loaded deck structures is one good, easy to spot for the average
consumer, misuse of cores. Make sure that the cored hull was AT LEAST
vacum bagged. DO NOT purchase a cored hull that was laid up by hand
without vacum bagging, plain and simple. These days Scrimp and other
resin infusion technologies make trusting a cored hull far easier.
The structural/weight advantages of using a cored hull are quite
dramatic, so one should not be scared into thinking that they are
unreliable...this is quie simply false. The comment about about
hiring a good surveyor is right on. Even then though, keeping what I
have said in mind can go a long way despite having a surveyor....the
vacum bagging for example. Even if the surveyor finds the hull
essentially sound, I would err on the side of safety and insist that
the hull you purchase was vacum bagged or resin-infused. Certainly
these days a surveyor can go a lot further with non-invasive laminate
testing, but ultimately the one buying the bboat should educate
him/herself as much as possible. Also, the moisture meter comment is
right on too. These are relatively inexpensive and easy to use. One
caveat, make sure the boat you are testing has been out of the water
for some time before you go sticking the meter into the hull. You'll
get misleading results if you try using it on a boat that has just
been pulled from the water (I've seen unscrupulous brokers/ yard
people trying to lure potential buyers of one boat to antother using
this technique).
-Eli





(hankh) wrote in message . com...
Look carefully at the construction. There is a world of difference in
how the cores are used. I am no fan of balsa. Won't use it anymore,
but in some cases it is adequate.
Hard to beat an experienced surveyor when buying a used boat.