In his book, "Boat Strength" Dave Gerr calls for 1/8 aluminum to have
framing or stiffeners every 6" or so (IIRC). This maybe overkill in most
small boats, but sounds like you could use some more. The lifting strakes
(spray rails?) sound like a good idea, if you can't easily access the
inside. Probably just a piece of angle iron welded on, use self-tapping
screws to pull the panel back closer to shape.

You definitely want a welder experienced with light-gauge aluminum; you can
get a lot of weld distortion.

Sal's Dad

-- "Don Backous" wrote in message
...
Looking for "words from the wise" here.
I have owned a 17', full-welded, aluminum hull boat for 11 years.
Over that time I have occasionally heard oil-canning coming from the bow
when going through moderate to severe chop (usually on the Columbia
River -
some excursions to the bays along the Oregon coast)
Recently, it seems the problem is becoming more evident and in fact I can
now see where the hull has "flattened" out between the chine and the keel
in
a short section between internal hull supporting members at the bow.
FYI..hull thickness is .125
The boat doesn't owe me a penny....really used it for these 11 years and
many a pacific Salmon has taken it's final nap in the fish box
;-)......however, no one makes a boat to match that I can find (the maker
of
my boat discontinued the model 10 year ago) so, while buying a shiny new
boat is appealing, I am looking to fix the problem rather than replace
the
boat.
The area of the hull that is affected is under a sealed compartment. Would
filling that compartment with 2-part expanding foam give me any relief or
would it just "mush" out when the hull deflects at wave impact?
I have also considered having a couple of lifting strakes welded to the
hull
across the offending area.
Any thoughts?
Thanks in advance!

Don
Vancouver, WA