boat hull design

[riveramunizaga]

Hello, my name is Cristian,this is my firth time here, and i would like to know somebody hellp me.

I have a powerboa 16´ vee fiverglass 22º 140hp looper, and i like to put in it a pad but i don´t know the dimensions (size), and how it comport in the boat, i have very much time driving boat, but never with pad, and i need the pad for more speed and woul like to know about the size of a box of water that the people do for blow off in final of transon and bow.

what is the difference between pad wide and one thin one, as it affects hull, how?

with this motor and 13.5 x 21 stanly steel propeller i got 51 mph

thank you.

[riveramunizaga]

nobary home

[marshmat]

140hp, 16-feet vee and you're running 51 mph? And you want yet more speed?
I'm guessing your boat's something like 750-900 kg in running trim? At 51 mph you probably don't have a whole lot of boat in the water there. A small pad could give you a bit more lift at the stern, yes.... but it seems like you're running so high out of the water anyway that the pad might cause it to pound on waves.
I'm not familiar with the calculations for retrofitting an existing hull with a pad; most boats I see with one have it built in from the start. Do be careful if you are going to modify the hull bottom as fibreglass boats have an integrated bottom structure that may fail if altered without careful planning.
Good luck, rivera.

[riveramunizaga]

thanks matt, bu i like to know what is small size in inchs. plese

[xxxscimitarxxx]

have a question regards pads......looking to fit pad to my 1970 21ft..deeeeeep v avenger hull.....200hp yam outboard......will use timber profile glue and screw for trials.....thinking along lines l have heard......pad width = prop diameter rule of thumb......however.....lm considering a taper longitudinally......my question is.....if as rule of thumb above applies for pad width.......is there rule of thumb for length.....

have attached simple autocad file for what lm thinking......

[chandler]

English

[xxxscimitarxxx]

yes....lm from england

[riveramunizaga]

who belive ? about pad width = prop diameter rule of thumb

[marshmat]

there isn't really a working rule of thumb for pad sizing.... i take it you're swinging a 14" dia. prop (approx), antivent plate is probably about 4-6" wide. Pad should end up somewhere between those dimensions. Where in there is trial-and-error or patience-and-computer-simulation.

[yipster]

article from jimboat

[Jimboat]

Pad design can be a tricky undertaking. hope the article helps. you can get download the full article at my web site.