small engine speed boat

[andrew k]

i run a 20hp mercury. it does about42mph i run off the tiller. i now have a flat bottom 14ft plywood boat that weighs about100lbs . i'm looking for a pattern for a boat that will help the performance of my motor.

 

[Paul Moir]

Re: small engine speed boat

I'm certainly no expert on racing runabouts, but an old trick for flat bottoms was to narrow out the running surface a bit by introducing a step. You could also try running the stepped surface out past the transom and then trim it until you get optimum trim (you know, the other kind. ).<br />I take it you've got the engine jacked up all the way, etc? Any setback? <br />And for home built plywood boat aficionados, what's you're boat modeled after? Any hope of a pic?

 

[andrew k]

Re: small engine speed boat

yeah i got my motor jacked pretty good. i'm just trying to get some inquieries on advancing the timing. i built the boat myself along with about 20 other boats running on the river with me. there a good strong and handling boat. sorry got no scanner at the time to send pics but i'll keep in touch and see what i can do.

 

[tashasdaddy]

Re: small engine speed boat

take pics, have developed and put on cd.

 

[Colin Grant]

Re: small engine speed boat

just interested what type of boat design this is...i have a coupple homebuilt wooden flat bottom runabout/speedboat and hydroplanes...

 

[andrew k]

Re: small engine speed boat

yeahi'll do that may take a while... keep in touch<br />any chnces of seeing yours.

 

[Always Broke]

Re: small engine speed boat

I’ll tell ya, if I had a 14’ boat that would do 42 MPH with 20 HP I’d be doing cartwheels. I just got rid of a 11’ semi V that was flat in the back, it had a 35 HP and couldn’t get over 25 MPH of course it didn’t weigh a 100#s though. I once had a cat type hull on a old 15’ Custom Craft that ran the same motor, the boat was heaver and would do 35. It had steps along the haul to break the suction made by a flat haul. You want to get as much boat out of the water as possible and still be able to control it, they can get pretty squirmy when you just have the prop in the water

 

[Laddies]

Re: small engine speed boat

42 with a fishing lower unit is great, it must be a pretty good hull, a 25XS runabout is only capable of about 65 MPH with quicky lower unit thats with 5 more HP and alot better lower unit, with a SS racing prop

 

[andrew k]

Re: small engine speed boat

whoni'm going top speed only about 2feet of the boat is in the water. the right wind will send you on a trip. a friend of mine runs a 30hp with 40 carbs on the same make boat. he runs on only the prop. i saw him do a complete 360% inthe air once. we run very fast motor on very light boats and over the past few years there only getting faster. the fastest thing on the river(miramichi) here is a 50hp merc. completely stock on a 15ft flat bottom. he's running 60+. that thing really moves his boat is the same pattern as mine but a bit wider. it wouldn't weigh over 150lbs. you should see him go

 

[Laddies]

Re: small engine speed boat

atk, you might try to find a tuning pipe out of a 25HP or have a prop shop remove some blade area and double cup the prop. We race D stock runabout and run 70+ with a 12' flat bottom and 44cu. in. Mercury engine. We have built a few hulls, 2 have won National Championships if you were running 25XS engines I could put you in touch with some help. You might get some help on HydroRacer.net

 

[andrew k]

Re: small engine speed boat

thanks captain, i'll check out hydro racer.<br />atk81