Custom Hydroplane Gearset?

[hi0npsi]

Hey guys,
I've taken a non-traditional route with my Yamaha 30hp on a competition boat because I'm in it for the recreation. I wanted neutral, reverse, electric start, push/pull steering and have a long history of good luck with Yamaha powersports equipment. I've overcome all obstacles except the gearing so far. At present I'm topped out at ~50mph on the GPS even with my custom Hill Marine propeller. I need to change my lower unit and/or gear set for more speed. The boat would probably pull a water skier up its got so much hole shot right now! I've read that I am likely somewhere around a 1.8:1 ratio and need to be in the 1:1 neighborhood. Ideas of who can build me what I need?

Proof of said recreation

http://www.youtube.com/watch?v=EHoLuw7Sfvs





Tom

[Ron Hill]

More Pitch and Diameter on the Prop

I think you need more pitch and maybe more diameter.

Jimmy Johnson and Rick Hoffman ran over 90 MPH with 30 HP Yamaha's twenty five years ago with stock gears.

[ZUL8TR]

What?

I think you need more pitch and maybe more diameter.

Jimmy Johnson and Rick Hoffman ran over 90 MPH with 30 HP Yamaha's twenty five years ago with stock gears.

How on earth did they get 30hp to overcome water and air drag at 90mph. The numbers do not seem to jive.
Do you have specifics on their setup?
What type boat?
Was this an official record set where?

[Dave M]

Re-Check Your #'s

A stock 25XSH runs at or near 80MPH. That is a known fact. Happens everytime one pulls the rope today. Is it really hard to imagine 90MPH with a 30 ? Especially a Yamaha. I doubt 90 will be seen without some mods to the engine though.

[hi0npsi]

Hmmm. I'd be open to trying more propeller Ron if you think it'll help. When I saw 50mph I was disappointed that the motor was running so well. At least if it ran poorly there would be an easy solution. I'm just curious how I can overcome such a large gearing gap to a Merc 44XS for example with propeller alone. Then again, I am not the expert here. Could you look up my order Ron? Would be under Tom Hughes from last summer. I'm in Vancouver, WA or Portland, OR depending on whether I shipped it home or to work. Let me know if there's room to move up on the propeller if you wouldn't mind.

Where might I find engine upgrades for this motor? I'm not opposed to anything to get this thing to pick up a bit. I'd be VERY happy if I could get it to do 65-70mph bursts and wouldn't want for more at that point. Do I have a factory rev limit that is being reached and preventing more speed? Can I increase RPM somehow?

Thanks a ton for the help guys!

Tom

[ZUL8TR]

25ssh records from APBA,

Bob Wartinger holds 25ssh kilo at 76.242 mph in a special Karelsen that's near 80 but much less comp average. As I said 90 mph with a 30 hp Yame and no quicki seems not likely.

Selections taken from link that I recently received from APBA. Maybe they have more recent 25ssh records but not provided.

https://www.apba-racing.com/sites/al...;20Records.pdf

Based on dates I assume all these records are with the short tower 25XS looper.

STOCK
25SSH
KILO
A
76.242
3/9/1997
OROVILLE, CA
JUMBO COCONUTS
FARLEY STREET
EDMONDS WA
BOB WARTINGER
SEATTLE WA
KARELSON
MERCURY

STOCK
25SSH
3 MI/3 LAP
A
60.828
9/17/1995
YELM, WA
AFTERBURNER
MIKE BARTLETT
FOREST GROVE OR
MIKE BARTLETT
FOREST GROVE OR
BLACKWELL
MERCURY

STOCK
25SSH
3 MI/4 LAP
A
57.328
8/23/2003
DAYTON, OH
ZOLKAR
JOE ZOLKOSKE III
APPLETON WI
JOE ZOLKOSKE III
APPLETON WI
BURNER
MERCURY

STOCK
25SSH
5 MI/3 LAP
A
66.372
9/13/1986
YELM, WA
ULTRA DART
DEAN HOBART
DEAN HOBART
DART CRAFT
MERCURY

STOCK
25SSH
5 MI/4 LAP
A
63.575
9/18/1994
YELM, WA
AFTERBURNER
MIKE BARTLETT
MIKE BARTLETT
BLACKWELL
MERCURY

[Dave M]

Kilo

1997............. props have come a long ways since then. I think a kilo record attempt today, the way Bob W does his Kilos, the speeds would suprise you. Kilo records are a lot different than competition records.

With your set up on that boat, I think 60 - 65 should be your goal.

[3autility]

hydro

You need to wear a helmet.

[hi0npsi]

1997............. props have come a long ways since then. I think a kilo record attempt today, the way Bob W does his Kilos, the speeds would suprise you. Kilo records are a lot different than competition records.

With your set up on that boat, I think 60 - 65 should be your goal.

Ok, so maybe just try more propeller or what are you suggesting?

You need to wear a helmet.

It's hard to see in the picture where I'm far away, but when I'm not just checking to see if my adjustments will allow it to maintain idle under way (big picture), I wear a helmet, life jacket and lanyard. I appreciate your concern though. Would be pretty stupid not to wear a helmet at these speeds.

Tom

[Ron Hill]

Mini Boat Years

Bob Wartinger holds 25ssh kilo at 76.242 mph in a special Karelsen that's near 80 but much less comp average. As I said 90 mph with a 30 hp Yame and no quicki seems not likely.

Selections taken from link that I recently received from APBA. Maybe they have more recent 25ssh records but not provided.

https://www.apba-racing.com/sites/al...;20Records.pdf

Based on dates I assume all these records are with the short tower 25XS looper.

STOCK
25SSH
KILO
A
76.242
3/9/1997
OROVILLE, CA
JUMBO COCONUTS
FARLEY STREET
EDMONDS WA
BOB WARTINGER
SEATTLE WA
KARELSON
MERCURY

STOCK
25SSH
3 MI/3 LAP
A
60.828
9/17/1995
YELM, WA
AFTERBURNER
MIKE BARTLETT
FOREST GROVE OR
MIKE BARTLETT
FOREST GROVE OR
BLACKWELL
MERCURY

STOCK
25SSH
3 MI/4 LAP
A
57.328
8/23/2003
DAYTON, OH
ZOLKAR
JOE ZOLKOSKE III
APPLETON WI
JOE ZOLKOSKE III
APPLETON WI
BURNER
MERCURY

STOCK
25SSH
5 MI/3 LAP
A
66.372
9/13/1986
YELM, WA
ULTRA DART
DEAN HOBART
DEAN HOBART
DART CRAFT
MERCURY

STOCK
25SSH
5 MI/4 LAP
A
63.575
9/18/1994
YELM, WA
AFTERBURNER
MIKE BARTLETT
MIKE BARTLETT
BLACKWELL
MERCURY

Check this link:

http://www.boatracingfacts.com/forum...+jimmy+johnson

When we started the Mini Boat Craze, my goal was a 40-42 MPH boat that we could race in the ocean. Ernie Dawe approved C-NOD as a APBA LOCAL class when he was APBA STOCK VP.

C was for 30 HP which had been C class, and NOD was National One Design.

We raced the class for about a year, then had the first Parker Mini Enduro.

We established O-Nod and U-Nod. O-Nod was a 40 tohatsu and U-Nod was anything under 32 cubic inches, as I didn't want Mercury's 44 running against Tohatsu's when Tohatsu was paying the bills.

Rich Hoffman, who later build V-8 Formula One Boats worked for Gran Prix and Jim Johnson worked for Ed Lane.

Hoffman and Johnson built three cylinder Yamhams using LA. Sleeves that were 32 Cubes. They made their own nose cones, welded on big skegs, use a water pick up for the cavitation plate. They ran 10 X 19 cleavers, and could curse at 90. This was pre capsule days. Hoffman broke his arm in a blow over, Blank Easau broke both shoulders at Parker.

OMC built the 45 to beat these Yamaha's but failed, so they ruled them out.

This is a copy of Jimmy's U-NOD prop, I sell them today with 10 spline and 13 splines.

C-NOD became C Production . O-Nod became Sport C. And U-Nod became Mod C. I think Jimmy had an official MOD C record of 90 something.

[hi0npsi]

That propeller appears to be the same one you sent and that I'm running. That said, any ideas?

[Ron Hill]

Sit The Prop Shaft

Two things, get a good life jacket and helmet, that one....Set the bottom of the gearcase even with the bottom of the boat. Plug the water pick ups on each side of the case, and make a water scoop that hooks to the cavitation plate....Be prepared to gain 10-15 MPH..

Three, run one in the boat for speed runs!...AND FOUR NEVER TEST A FAST BOAT WITHOUT A CHASE BOAT IN THE WATER WITH THE MOTOR RUNNING AND SOMEONE DRIVING THAT HAS SEEN BLOW OVERS BEFORE.


THESE GUYYS RACE ALL THE TIME : https://www.apba-racing.com/sites/al...;20Records.pdf

[ZUL8TR]

90 mph speed of Johnson and Hoffman

Check this link:

http://www.boatracingfacts.com/forum...+jimmy+johnson

When we started the Mini Boat Craze, my goal was a 40-42 MPH boat that we could race in the ocean. Ernie Dawe approved C-NOD as a APBA LOCAL class when he was APBA STOCK VP.

C was for 30 HP which had been C class, and NOD was National One Design.

We raced the class for about a year, then had the first Parker Mini Enduro.

We established O-Nod and U-Nod. O-Nod was a 40 tohatsu and U-Nod was anything under 32 cubic inches, as I didn't want Mercury's 44 running against Tohatsu's when Tohatsu was paying the bills.

Rich Hoffman, who later build V-8 Formula One Boats worked for Gran Prix and Jim Johnson worked for Ed Lane.

Hoffman and Johnson built three cylinder Yamhams using LA. Sleeves that were 32 Cubes. They made their own nose cones, welded on big skegs, use a water pick up for the cavitation plate. They ran 10 X 19 cleavers, and could curse at 90. This was pre capsule days. Hoffman broke his arm in a blow over, Blank Easau broke both shoulders at Parker.

OMC built the 45 to beat these Yamaha's but failed, so they ruled them out.

This is a copy of Jimmy's U-NOD prop, I sell them today with 10 spline and 13 splines.

C-NOD became C Production . O-Nod became Sport C. And U-Nod became Mod C. I think Jimmy had an official MOD C record of 90 something.

Ron from what I read in the link you post above it looks like they had a modded engine that was more than 30 hp if so the speed is possible not knowing what exactly was modded.

[ZUL8TR]

records

1997............. props have come a long ways since then. I think a kilo record attempt today, the way Bob W does his Kilos, the speeds would suprise you. Kilo records are a lot different than competition records.

With your set up on that boat, I think 60 - 65 should be your goal.

I do not doubt that props are improved but as I said this is what APBA sent me.

[johnsonm50]

Looks to be running deep, set up is as key to speed as the right stuff. You are also heavy & worse yet, top heavy with a full fishing motor. There is potential for a good amount more than 50 just that it will be harder to find as you improve & more of a handful to drive.