Re: Cores and composites, etc why on a Bolger?
Since the boxes really don't in my view lend themselves all that well
to either lightening, or high budgets, why use core? There aren't a
slew of reasons why I would, and other than transoms no projects
where it has come up. But here are some places.
- Charter boats. Core decks are the easiest to lay, and strongest
surfaces for a charter boat for the cost or weight. Thinking of the
ply, balsa, biax decks.
- Multihulls. Double eagle is a charter cat, and it isn't the only
one he has drawn. I don't know the design well enough, but often cats
have large deck areas, and weight is an issue, so is maintenance, and
you have to use a level of materials that will allow certification,
so core becomes attractice.
- Where there are deck beams core allows one to eliminate them, and
get more room, this may be of particular merit if the space is
cramped, or you are just the wrong side of standing head room. If
one compares the 3/8- 3/4" materials (3/8" ply vs 1/8" skins over
1/2" core, you should pick up a little over 8x the stiffness for the
same weight, so you don't need to be a PE to make substitutions where
the usual span increase will probably be only 2-3 times, anyway the
transverse distance may rule.
-Where there aren't deck beams, some Bolger boxes have been
criticised for having weak decks, understandable since the walkees
can be of all sorts of weight, so again core might be an easy sell.
-Transoms. On the smaller boats, these kind of details are often
quite a lot of the weight, if you prefer the look or performance of a
solid rather than a framed transom, core could have a role.
to either lightening, or high budgets, why use core? There aren't a
slew of reasons why I would, and other than transoms no projects
where it has come up. But here are some places.
- Charter boats. Core decks are the easiest to lay, and strongest
surfaces for a charter boat for the cost or weight. Thinking of the
ply, balsa, biax decks.
- Multihulls. Double eagle is a charter cat, and it isn't the only
one he has drawn. I don't know the design well enough, but often cats
have large deck areas, and weight is an issue, so is maintenance, and
you have to use a level of materials that will allow certification,
so core becomes attractice.
- Where there are deck beams core allows one to eliminate them, and
get more room, this may be of particular merit if the space is
cramped, or you are just the wrong side of standing head room. If
one compares the 3/8- 3/4" materials (3/8" ply vs 1/8" skins over
1/2" core, you should pick up a little over 8x the stiffness for the
same weight, so you don't need to be a PE to make substitutions where
the usual span increase will probably be only 2-3 times, anyway the
transverse distance may rule.
-Where there aren't deck beams, some Bolger boxes have been
criticised for having weak decks, understandable since the walkees
can be of all sorts of weight, so again core might be an easy sell.
-Transoms. On the smaller boats, these kind of details are often
quite a lot of the weight, if you prefer the look or performance of a
solid rather than a framed transom, core could have a role.
--- In bolger@y..., "pauldayau" <wattleweedooseeds@b...> wrote:
little tricky, but there is better availability of sealed core for
epoxy use these days.
I had the
> has anyone looked at end grain balsa for coring. ive seen it usedThis is a great material along with ply and epoxy, see my other post.
> for bulkheads and hull skins .
> Apparently it sticks better to polyester resin, than epoxy.wprks great with epoxy, I have used mostly raw core which is just a
> You could buy it as thin as 1/4 ".
little tricky, but there is better availability of sealed core for
epoxy use these days.
> A 3/4 thick piece with 10 oz cloth on each side was used on aThat is a stiff but not terribly strong composition.
> record breaking car as a firewall behind 2 merlin v12's.
I had the
> job of sanding the car It aws only 40' long.
> Cheers paul
End grain balsa has been used aboard boats almost as long as there have been
FG boats. Most often used to core curved areas on decks. Used some what less
as coring for hull. Big problem is letting water soak into it. You must
religiously seal all exposed core openings and mounting holes. My Columbia
deck has a mix of 3/8" plywood squares in the flat deck areas and end grain
balsa where there is more curvature.
ps: My Columbia was designed by Alan Payne, from down your way...
Paul W. Esterle
Capt'n Pauley Video Productions
423.989.3159
S/V Bryn Awel, Columbia 10.7
Bristol, Tenn. USA
http://www.captnpauley.bigstep.com
http://pages.preferred.com/~pesterle/
FG boats. Most often used to core curved areas on decks. Used some what less
as coring for hull. Big problem is letting water soak into it. You must
religiously seal all exposed core openings and mounting holes. My Columbia
deck has a mix of 3/8" plywood squares in the flat deck areas and end grain
balsa where there is more curvature.
ps: My Columbia was designed by Alan Payne, from down your way...
Paul W. Esterle
Capt'n Pauley Video Productions
423.989.3159
S/V Bryn Awel, Columbia 10.7
Bristol, Tenn. USA
http://www.captnpauley.bigstep.com
http://pages.preferred.com/~pesterle/
----- Original Message -----
From: "pauldayau" <wattleweedooseeds@...>
To: <bolger@yahoogroups.com>
Sent: Friday, August 30, 2002 8:19 AM
Subject: [bolger] Cores and composites, etc
> has anyone looked at end grain balsa for coring. ive seen it used
> for bulkheads and hull skins .
> Apparently it sticks better to polyester resin, than epoxy.
> You could buy it as thin as 1/4 ".
> A 3/4 thick piece with 10 oz cloth on each side was used on a
> record breaking car as a firewall behind 2 merlin v12's. I had the
> job of sanding the car It aws only 40' long.
> Cheers paul
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - add your comments at the TOP and SIGN your posts and <snip> away
> - To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
01930, Fax: (978) 282-1349
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> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
>
> Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/
>
>
has anyone looked at end grain balsa for coring. ive seen it used
for bulkheads and hull skins .
Apparently it sticks better to polyester resin, than epoxy.
You could buy it as thin as 1/4 ".
A 3/4 thick piece with 10 oz cloth on each side was used on a
record breaking car as a firewall behind 2 merlin v12's. I had the
job of sanding the car It aws only 40' long.
Cheers paul
for bulkheads and hull skins .
Apparently it sticks better to polyester resin, than epoxy.
You could buy it as thin as 1/4 ".
A 3/4 thick piece with 10 oz cloth on each side was used on a
record breaking car as a firewall behind 2 merlin v12's. I had the
job of sanding the car It aws only 40' long.
Cheers paul