hydro turning

[thunderstruck]

hi
I'm in Australia so l don't know many of the classes you guys run over there.
i am wondering how a 18 hp tohatsu/nissan would go on a hydro?
the class the we run has no weight rules so it could be built super light
how sharp can a hydro corner as we run single bouy turns.
has any one ever ran a sit down hydro ?
thunderstruck
happy

[johnsonm50]

hi
I'm in Australia so l don't know many of the classes you guys run over there.
i am wondering how a 18 hp tohatsu/nissan would go on a hydro?
the class the we run has no weight rules so it could be built super light
how sharp can a hydro corner as we run single bouy turns.
has any one ever ran a sit down hydro ?
thunderstruck
happy

From messing around with a few hydro's in play with fish motors & racers Id say you can get it to handle fairly well in a sharp turn. Since the motor you state probably has right hand prop spin that can be used to power slide it around some, thing is straightening up smoothly where you want it. Sitting will limit handling as opposed to kneeling but Ive done it & seen it done fairly well. Problems being you want to be free of obstruction & not be trapped if you go over [no legs under frame, deck or cable] & in 'the right place' while being able to reach the wheel & throttle ok. With the added height of a fish motor stability in sharp turning can be an issue. While the upper weight wants to pull the boat over the outside of the turn, the prop thrust counters that by pushing the bottom under. It will be important for your set up to have traction thru the turn. That would probably mean a fair amount of depth & tuck which can effect speed in the straight. To consider how much straightaway you run compared to turn distance might help find the sweet spot. Only way to know how it will be is try it & the only way to overcome what it is is practice. A poor handling rig can 'look good' in the right hands LoLs & Good Luck. sounds like fun.

[johnsonm50]

From messing around with a few hydro's in play with fish motors & racers Id say you can get it to handle fairly well in a sharp turn. Since the motor you state probably has right hand prop spin that can be used to power slide it around some, thing is straightening up smoothly where you want it. Sitting will limit handling as opposed to kneeling but Ive done it & seen it done fairly well. Problems being you want to be free of obstruction & not be trapped if you go over [no legs under frame, deck or cable] & in 'the right place' while being able to reach the wheel & throttle ok. With the added height of a fish motor stability in sharp turning can be an issue. While the upper weight wants to pull the boat over the outside of the turn, the prop thrust counters that by pushing the bottom under. It will be important for your set up to have traction thru the turn. That would probably mean a fair amount of depth & tuck which can effect speed in the straight. To consider how much straightaway you run compared to turn distance might help find the sweet spot. Only way to know how it will be is try it & the only way to overcome what it is is practice. A poor handling rig can 'look good' in the right hands LoLs & Good Luck. sounds like fun.

I wrote all that just assuming you'd be turning 'left' -hope that's right.

[STEVE FRENCH]

We tested the 18hp tohatsu a few years back with the OMC-A foot....I ran it several times in BSH as a proto type....It peformed well (Approx 55-58MPH) but lacked 2-3 MPH on the Hot-Rods so it never was accepted.....I like it and would think it would perform decent "as is"/fish'n gearfoot, on a hydro.....take a look at the B-1 Bomber AOF class.. https://hydroracer.net/forums/showthread.php?t=20674 ..you could be on to something fun and CHEEP ta run.....KEEP IT SIMPLE/FUN!!!!
......100N

Sit down might work with a larger boat....but might need ta keep seat movable ta git on plane then slide back ta git lift in front end......corners will be were your v-bottoms/tunnels/runabouts....... will perform better?......especially on a single bouy turn.............

http://www.boatracingfacts.com/forum...ad.php?t=11843

[johnsonm50]

My pal Reeves sits in this & handles it very well, I dont feel comfortable driving it but have to say it handles good considering.

[AZ Outlaw]

A stock hydro (15hp OMC) heat with a tight two buoy turn from Parker, AZ. Lottsa fun!

<iframe width="480" height="390" src="http://www.youtube.com/embed/KtuxlAqr4VI" frameborder="0" allowfullscreen></iframe>

[thunderstruck]

thanks for the reply guys
yes i will be turning left i think i would prefer to be seated because i am used to it.
i would also prefer the boat to be around 11-13 ft long
and weigh under 40kgs {88lbs}
also could someone please post some pics of the boats being run in the b1 bomer class.
thunderstruck

[jeff55v]

How smooth are the water conditions you plan to race in?

[thunderstruck]

How smooth are the water conditions you plan to race in?

from glass to a small chop <1ft

[jeff55v]

from glass to a small chop <1ft

If that is the case then, you will need an "A" class hydro. Around 8.5 to 9 feet long. That should be pretty close to optimal for a 18hp Tohatsu.
(11 to 13 feet long is huge for that motor)
Boats this small work best when the driver is kneeling, because the driver is such a large percentage of the weight of the entire package. Being able to move around in the boat for various situations will give a big advantage over sitting in a fixed position.
Just my opinion. Have fun with this.

http://www.boatracingr11.com/sorense...lane__kits.htm

[thunderstruck]

weight isn't an issue as l am sponsored by a company that builds ultra light foam panels that are fireproof,waterproof rot proof 70%lighter than marine ply and 80%stronger.
so the boat will be made out of this ,carbon fibre and vacuum infused
l also weigh 165 lbs race ready and l'm not going to get any lighter.
the tohatsu should be producing around 19-20 HP
thunderstruck

[johnsonm50]

weight isn't an issue as l am sponsored by a company that builds ultra light foam panels that are fireproof,waterproof rot proof 70%lighter than marine ply and 80%stronger.
so the boat will be made out of this ,carbon fibre and vacuum infused
l also weigh 165 lbs race ready and l'm not going to get any lighter.
the tohatsu should be producing around 19-20 HP
thunderstruck

Its good you can get that done as large & still be light, in a way the larger the boat [to a point] the better. If its big enough you could throw the wheel to the stop & be ok.
Jeff's still right about size tho because you still have to consider drag across the water & thru the air. C boats are 10', for a motor of A to B size I think B size to be best, a little bigger than A & real light as composite.

[sam]

Even with the most advanced panels, weight will still be an issue. You have to use some kind of glue or resin and that will be the majority of the weight, not the panels themselves.

[Aussie Steve]

I would say "A" size to mate but defiantly kneeling through the one bouy turns your going to want to move forward back and lean ,with the whole class trying to get around a sharpe turn it will get lumpy .

[jeff55v]

A 20hp motor on an "A" hydro should top out at 40mph with a stock lower unit. 55mph with a racing lower unit.
Do you plan to build this boat using your own design, or a design of somebody else's?