"Short Wave Sportfishing" wrote in message


The wider the surface, the more surface area for grip and vice versa.


But the wider the surface the less weight is on each square inch...so my
understanding
is the overall friction is the same. But I'm not sure.



If you have four lifting points, why not use tow straps and use the
winch to pull the boat forward until it's sound against the bow stop?

Nope, just two lifting points. Pulling from the stern one is not practicle
cause the windsheld is between. We can pull a bit on the bow lifting
ring, but it's really made for...uh...lifting. I don't think it should be
pulled
with more than a few hundred pounds pressure.



Or get a crane for a tow vehicle. :)


Hmmmmmm..........


Later,

Tom

Thanks for the ideas, Tom.

Gary

Gary wrote:

"Short Wave Sportfishing" wrote in message

The wider the surface, the more surface area for grip and vice versa.



But the wider the surface the less weight is on each square inch...so my
understanding
is the overall friction is the same. But I'm not sure.



If you have four lifting points, why not use tow straps and use the
winch to pull the boat forward until it's sound against the bow stop?


Nope, just two lifting points. Pulling from the stern one is not practicle
cause the windsheld is between. We can pull a bit on the bow lifting
ring, but it's really made for...uh...lifting. I don't think it should be
pulled
with more than a few hundred pounds pressure.



Or get a crane for a tow vehicle. :)



Hmmmmmm..........



Later,

Tom


Thanks for the ideas, Tom.

Gary


Put in a bow eye, with a cable run to the transom, to share the load.
You can remove or install it at will

On Tue, 15 Mar 2005 17:09:24 -0500, "Gary"
wrote:


"Short Wave Sportfishing" wrote in message


The wider the surface, the more surface area for grip and vice versa.

But the wider the surface the less weight is on each square inch...so my
understanding is the overall friction is the same. But I'm not sure.

That is true, but less pressure per square inch is compensated for by
the area. What has more friction - 4k psi on a half inch square or 4k
psi on ten square feet? The answer is it depends.

The problem with figuring friction is that there are any number of
variables which enter into any mathematical construct for existing
materials. To develop the COF, you have to develop two points - the
breaking force (described as the weight, acceleration or energy
required to make one material slide against another) and the sustained
force (that which allows one material to continue to slide against
another).

You could certainly develop the COF from some simple experiments, but
I'm afraid you might damage your boat. :)

I think what you are really looking for is how to configure the bunks
such that the boat is properly supported and how to keep it from
moving which, admittedly, has something to do with friction, it really
has more to do with configuration.

You could so something that I saw once and that's make the front of
the bunks lower that the rear of the bunks - that way the weight is
forward and with proper application of wax, it would probably stay
that way.

Later,

Tom