To High Fill Or Not?

[Harry Kosta]

Hello every body,long time since my last post.
I have a Question that I need some feedback on.
While building my big boat out of 6mm Alloy plate naturally did not get or very
little distortion.
On the small boat that I'm building at the moment 3mm plate.
The bottom of the hull looks like the bloody sand dunes.
Ripples every where(mostly from the centre back).
The boat has got to to close to 50mph when finished(hoping)
Would this concave some as deep as 10mm (450mmx450mm) affect performance?(looks crap) or should I high fill them with microballoons(bog/filler)
Would this filler crack when loading the boat on it's trailer?
Will be painting the bottom sides with polyurethane 2pack.
Any Ideas ?

Hazza

[Brent Swain]

It has no effect below the waterline. The German boat that raced in the one ton cup in Auckland in the 70s looked like a bucket that survived a buffalo stampede, but the designers believed that the weight of fillers would cost more in performance than the humps and hollows, as long as they were smooth humps and hollows.. Hollows can be jacked out from the inside with a hydraluic jack on a post and held there by welding a short stringer under it. Humps can be similarly done from the outside. These short stringers will be covered in sprayfoam and will never be seen again, so it doesn't matte rwhat they look like.This is a far better option than filler ,as it will never fall off.
Brent

[Harry Kosta]

Thanks for the reply Brent.
As it's been awhile since I asked the Q, I when ahead with straighting as much as possible ,then epoxied undercoated the underside.
I used Q-cell as afiller upto 5-7mm thick in some areas 1mm in majority.
I sealed it with 2 coats of undercoat than I used a co-polymer paint.
It looks and fills like ceramic very strong and hard to apply smoothly.
It's supposed to be 40% stronger than Polyurethane and it adhesives to 8000psi compared
to 1800psi .
See what happens

Hazza