View Single Post
  #2   Report Post  
DSK
 
Posts: n/a
Default

Gary wrote:
Background then Question:

We have a problem where our trailered boat does not set properly on the
trailer.


You need a set of bunks conformed to the hull shape.


On most boat there is, of course, a bow-eye and you just pull the boat
forward with a winch. But this boat is an older wooden boat. It does not
have a bow-eye and we can not install one -- it would just pull the bow out
of the boat.


I hope that's not true, if so your boat is seriously underbuilt. A
wooden boat will have stem & keel members, they should be strong enough
to lift the boat much less pull it onto a trailer.

It would be worth your while to install a bow eye, and if it needs some
backup structural work, so be it.


So...my QUESTION:

The boat weight about 4000 lbs. I've done a little googeling and read about
coefficient of friction.

#1: Am I right in thinking the Coefficient of Friction can not be more than
1.0
In other words, the MAX force needed to pull the boat forward is 4000
lbs.


No. Max CFr can be far greater than 1, in theory it can reach infinity.
In normal circumstances, sliding friction ranges from about .2 to .7 but
it can be reduced with substances called "lubricants" and increased with
substances called "glue." Dazzling new technology


#2: The boat (painted wood) sets on four carpeted bunks. Am I right in
understanding
that the amount of surface area between the boat & bunks does not matter as
far as
increasing or decreasing the friction?


That's pretty much correct, for most surfaces the decrease in load
bearing matches the increase in friction due to surface area.

My suggestions- check the weight distribution on the bunks, try to get
more of the weight onto the trailer rollers... try changing the carpet
surface... add a set of transverse bunks conformed to the hull shape...
use slippery bottom paint...

Fair Skies
Doug King