engineering for weight transfer

[afrhydro]

on a hydroplane
how do you determine the amount of foot print the sponson would need to
hold the boat up and have the tail off the water
im stuck now
i went the other way to much stern lift and its bearing the sponsons and causing a steering issue

[Jango]

I would think a "Slight" change in motor angle and/or moving weight to stern would help? You might need to make sponsons wider (10 - 20%) - probably trial and error? I would think it has to do with amount of Speed. Do you have a Fin on one or Both sponsons?

[afrhydro]

no fin on either one
my problem starts at about 60 65
its running about up to the fl number that area under there the foot print if you will is only 6 inches wide
but i dont know how deep
just from eye witnesses
my theroy is to go about 12/14 inches wide
i had this problem with my first design and the fatter i made it the better it got
and the step made some good lift
now i lost that lift some how with more power and moving weight forward
now im out of balance again
so theres no real rule of thumb so to speak as to how much foot print is best

[Jango]

Is it posible (practical) to bolt on a "Ski Like" shape on the inside of the sponsons? If posible, might save alot of time determining optimum width.

John G.

[afrhydro]

im scaping it and building a new one

[afrhydro]

i found the problem and i might be able to save part of the design
one we know my foot print on the sponsons is to narrow
and the amount of aero lift has to match bow to stern

a real easy boat to build but the most complicated for synchronizing and balancing all the lift and drag
the sponsons are going to have some major shape changes