"Stephen B." wrote in

I understand your resoning, but you are actualy not helping yourself much.
You are proposing to attatch the stress load of the boat on the cross bar
at the point that the beam stifness changes. The load would be slightly
higer where you are not stifening (added weight of the stifening). If you
look at http://www.classictruss.com/roof_truss_facts.asp their is a reson
all the trusses shown have both the uper and lower span coming to the
bearing point . For ease of manufacturing, you may want to consider a
Modified "2x4 roof truss". make to laders with only a couple of short
cross brases (at load locations). or if you have some small stell, make
thboth trusses like one side of
http://www.garrettsbridges.com/wp-co...ss-bridge5.jpg
heavy outer beams and thin stock stringers between them.

This will deliver the load from
the center I beam to the containers directly instead of just stiffening
the middle of the cross bars. Leaving the "boat hooks" mid span on your
cross bars should not be a problem. I am sure you would think of it, but
I would also weld 4 stops to the cross bars so they can not slide across
the roofs of the containers.


This will be used to lift items that are in the less than 250# range 99% of
the time. For the boat, it will be only to lift it long enough to get some
cribbing under it, and it will be lifted about two inches off the trailer.
I have no reservations that this will hold the front (empty) end of a 16'
aluminum boat.

Steve