I spoke to a fellow that has used it, and he
told me that sanding kevlar leaves fibers poking
out of the surface. He recommended either
fairing it, or laying it up with one layer of glass
on the outer layer for fairing.

Have you used it?


"DSK" wrote

Well, Kevlar isn't that expensive. Actually a heavy gage Dynel laid up w
epoxy would probably be effective at lower cost. You could put it over
key parts of the boat... I'm thinkin about the forefoot, keep those
shipping container worries to a minimum.

Bart Senior wrote:
I spoke to a fellow that has used it, and he
told me that sanding kevlar leaves fibers poking
out of the surface. He recommended either
fairing it, or laying it up with one layer of glass
on the outer layer for fairing.

Have you used it?


Yes, and your friend was right. There is no way to sand a Kevlar lay-up
smooth. I helped a friend put a layer of Kevlar on the bow of his
catamaran, we used a layer of medium density fairing compound over it
and ther are a few spots that show stubble... you have to look real
close, and after painting on anti-foul it's not visible. I hope no
future owners sands the forefoot(s) (forefeet?) too agressively.

A better method might be to lay a layer of very fine FG cloth over the
Kevlar, or a light type of scrim. Or, if you're building the whole thing
from scratch, put the Kevlar in the middle of the laminate.

I was thinking of using a mix of Kevlar and carbon fiber on the dinghy,
but have decided to go with just CF.

DSK

What do you think it will weigh we completed?

"DSK" wrote

I was thinking of using a mix of Kevlar and carbon fiber on the dinghy,
but have decided to go with just CF.

Again, this has wandered far from the original subject, please excuse
the title switch.


I was thinking of using a mix of Kevlar and carbon fiber on the dinghy,
but have decided to go with just CF.


Bart Senior wrote:
What do you think it will weigh we completed?


The bare hull should (if my math is right) weight around 12 pounds.
That's without vacuum bagging, which I may experiment with but it looks
like too much of a PITA to save only 2 ~ 3 lbs max. Adding seats, gun'l,
etc etc will probably bring it up to 25 ~ 30 lbs.

This is for a 9' Whitehall style boat, so I'm won't be disappointed if
it comes out at the high end of this range, that's still less than half
what a Walker Bay 8 is (and IMHO they are tippy, ugly, junk... hey at
least they're inexpensive).

Fresh Breezes- Doug King

I agree on the Walker Bay boats. Something
about them makes be cringe.

So you don't think your's will be tippy? It is
light, even if wide and with a flat bottom I'd
think it would still be tippy.

"DSK" wrote in message
.. .
Again, this has wandered far from the original subject, please excuse
the title switch.


I was thinking of using a mix of Kevlar and carbon fiber on the dinghy,
but have decided to go with just CF.


Bart Senior wrote:
What do you think it will weigh we completed?


The bare hull should (if my math is right) weight around 12 pounds.
That's without vacuum bagging, which I may experiment with but it looks
like too much of a PITA to save only 2 ~ 3 lbs max. Adding seats, gun'l,
etc etc will probably bring it up to 25 ~ 30 lbs.

This is for a 9' Whitehall style boat, so I'm won't be disappointed if
it comes out at the high end of this range, that's still less than half
what a Walker Bay 8 is (and IMHO they are tippy, ugly, junk... hey at
least they're inexpensive).

Fresh Breezes- Doug King

Bart Senior wrote:
I agree on the Walker Bay boats. Something
about them makes be cringe.


The bow is too pointy, they don't have the right sheer, and the stern is
ugly. However, the little wheel in the skeg is a nice touch.


So you don't think your's will be tippy? It is
light, even if wide and with a flat bottom I'd
think it would still be tippy.

Well, tippy is relative. The design does not have a flat bottom, but
rather an elliptical arc that is shallow enough to just let the bilge
ride above the waterline when lightly loaded, or when making waves. The
bilge is relatively wide & firm, not such a great shape for rowing
(rowing shells tend to have narrow hulls & slack bilges, which is why
they are so tippy) but better than a flat bottom & hard chine, and not
noticably worse for rowing (I hope) than the traditional slack-bilge
rowing dinghy because of the reduced wetted surface.

I monkeyed around with a hull plan program for about 6 months, looking
at the various numbers. I got to where the lines plotted to about 90% of
the stability of an inflatable (whereas a Fatty Knees is about 65%) and
the drag pretty much the same as the rowing dink.

The cost will be less than a brand new fiberglass rowing dink, too; but
it will still be a lot more than a Walker Bay or a plywood pram. In all,
I'm pretty eager to see what it comes out like.

Fresh Breezes- Doug King

I like the wheel too. But one friend told me
it was not particularly helpful, but he could not
give me a good reason why not. I saw him use
it once and it seems to work well.

So when are you building this dink? Over the
winter for a winter project?
..
"DSK" wrote
Well, tippy is relative. The design does not have a flat bottom, but
rather an elliptical arc that is shallow enough to just let the bilge
ride above the waterline when lightly loaded, or when making waves. The
bilge is relatively wide & firm, not such a great shape for rowing
(rowing shells tend to have narrow hulls & slack bilges, which is why
they are so tippy) but better than a flat bottom & hard chine, and not
noticably worse for rowing (I hope) than the traditional slack-bilge
rowing dinghy because of the reduced wetted surface.

I monkeyed around with a hull plan program for about 6 months, looking
at the various numbers. I got to where the lines plotted to about 90% of
the stability of an inflatable (whereas a Fatty Knees is about 65%) and
the drag pretty much the same as the rowing dink.

The cost will be less than a brand new fiberglass rowing dink, too; but
it will still be a lot more than a Walker Bay or a plywood pram. In all,
I'm pretty eager to see what it comes out like.