Thunderboat Setup

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Mike Hughes

Well-Known Member
Vendor
Joined
Feb 23, 2003
Messages
4,382
So I have my T boat rigged and ready to go in the water. Just with a seal coat. Want to run it first, before I go ahead and paint it up as the 69 notre dame. Just incase I need to make changes. Looking for a good start point on pipe length and prop choice. It is a scratch built boat. Not sure what a stock PUM is going to pull. I have some prop choices that I need to S/B. 6717/3, 6719/3, 6520, 7016. Would be nice not having to do all them by saturday. Also have a few others that I doubt it will pull. 2818, 2916/3, 3016.

The pipe is the 2" gizmo ALU pipe w/internal stinger. What is a good length?

Any other props I should try?

Thanks

Mike
 
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So I have my T boat rigged and ready to go in the water. Just with a seal coat. Want to run it first, before I go ahead and paint it. Just incase I need to make changes. Looking for a good start point on pipe length and prop choice. It is a scratch built boat. Not sure what a stock PUM is going to pull. I have some prop choices that I need to S/B. 6717/3, 6719/3, 6520, 7016. Would be nice not having to do all them by saturday. Also have a few others that I doubt it will pull. 2818, 2916/3, 3016.

The pipe is the 2" gizmo ALU pipe w/internal stinger. What is a good length?

Any other props I should try?

Thanks

Mike
Mike, S/B the 6717/3 first and give it a try.
 
I started out with the 7016 back cut props we once ran on cats. That was a good start for top end, but smaller props race better. I've been running a cut down 6717 the last few years. I think it's about 61 mm diameter. Both are three blades, but I have a selection of 70 mm two blades and some smaller 3 blades. Brian is bringing his Thunderboat Saturday. I'll bring my prop collection as well so you can try some props before you spend a lot of time.

I have no experience with your pipe. A reasonable starting point would be 12 to 12 1/2 inches from the engine flange to the start of the band. The final length will depend on the prop. Break in makes a difference. We put around 50 dyno runs on my engine before we put it in the boat. Some people have reported problems with piston seizing, but I haven't had any issues.

Lohring Miller
 
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I did have the piston stick after the first couple of runs in the hydro. Left a nice mark at the top of the piston on the exhaust side. Guess I will work on the 7016 and 6717. I have a bunch of 1667 that would probably work well too.

Mike
 
I did have the piston stick after the first couple of runs in the hydro. Left a nice mark at the top of the piston on the exhaust side. Guess I will work on the 7016 and 6717. I have a bunch of 1667 that would probably work well too.

Mike
Not sure about this Mike but I think I did read something on Jim's about removing .002" from the top of the piston.
 
Yeah I know about that. Problem is, not legal for T boat then. No mods allowed to internal of motor.

Mike

PS Went crazy and sharpen the whole bunch. Figure I did not want to do them later. Even found a few more to do. 6 total. Only ruined one. It was the 6520. I think it was so out of balance to begin with. I cant thin the blade any more and it is still too heavy.
 
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Yeah I know about that. Problem is, not legal for T boat then. No mods allowed to internal of motor.

Mike

PS Went crazy and sharpen the whole bunch. Figure I did not want to do them later. Even found a few more to do. 6 total. Only ruined one. It was the 6520. I think it was so out of balance to begin with. I cant thin the blade any more and it is still too heavy.
Try a 2716 and pull the pipe out to 13 inches. Pulling off the corner is key with these boats,bog the motor and go to the rear fast.. :p
 
Yeah I know about that. Problem is, not legal for T boat then. No mods allowed to internal of motor.

Mike

PS Went crazy and sharpen the whole bunch. Figure I did not want to do them later. Even found a few more to do. 6 total. Only ruined one. It was the 6520. I think it was so out of balance to begin with. I cant thin the blade any more and it is still too heavy.
Try a 2716 and pull the pipe out to 13 inches. Pulling off the corner is key with these boats,bog the motor and go to the rear fast.. :p
Yep, 2716 is a good all around prop with good corner speed.
 
Thanks everyone for your help. I was able to set the NAMBA 2 lap record for T boat yesterday with all your suggestion.

Mike
 
Ok Mikey, here is what I did. First time on the water, needles where off so brought it back in and adjusted. Threw it back out and try to run a time. Just was not handling very well. I kind of guessed on the strut and turn fin locations because there was no room on the work bench at home to do the setup. In it came and we passed on the rest of our time. So back to the pits and raised the strut a 1/4, pushed the pipe in 3/4" and tweaked the fin. Next turn round, threw it in and ran a 27.81. New record. This was with the 6717/3. So now the record was in the bag, tried a few other props. 7016 was too much. Then went with a 6520/3 that Brian Buaas suggested. Bingo. Ran a 27.31. It bogged coming out of the left turn on the second lap and could of turned the right turn better as well. I was thinking we could shave another .5 sec off of the 27.31. So for the rest of the afternoon, the duck where out in force. I had to hurd them out of the way and drive around them. I can not turn left at all at full speed and blew it off 4 times in multiply attempts avoiding ducks. Finally said that was it and put it away. I got tired of rowing. The boat needs 3 changes that I will work on. More weight in the left. I have 14oz in it so far. Also I think I will work on a gifferent version of my new Tboat fin. I believe it needs more rake in the leading edge. It has been run on 3 different boats with the same results. Also go to try and set up the rudder some so it does not effect the boat as much in left trim. I think the pipe ended up being at 11.75 or so when we where done.

Now for the biggest secrect of all. Boat was designed by my good friend Russ Nachtweih. The boat runs awesome down the shute and in the corners. Like it is on rails. Without the ride of the boat it would of not been possible. Thanks Russ. Cant wait till the fall 2 laps to come so we can push the boat more. Should have a good handle of it by that time.

Mike
 
Ok Mikey, here is what I did. First time on the water, needles where off so brought it back in and adjusted. Threw it back out and try to run a time. Just was not handling very well. I kind of guessed on the strut and turn fin locations because there was no room on the work bench at home to do the setup. In it came and we passed on the rest of our time. So back to the pits and raised the strut a 1/4, pushed the pipe in 3/4" and tweaked the fin. Next turn round, threw it in and ran a 27.81. New record. This was with the 6717/3. So now the record was in the bag, tried a few other props. 7016 was too much. Then went with a 6520/3 that Brian Buaas suggested. Bingo. Ran a 27.31. It bogged coming out of the left turn on the second lap and could of turned the right turn better as well. I was thinking we could shave another .5 sec off of the 27.31. So for the rest of the afternoon, the duck where out in force. I had to hurd them out of the way and drive around them. I can not turn left at all at full speed and blew it off 4 times in multiply attempts avoiding ducks. Finally said that was it and put it away. I got tired of rowing. The boat needs 3 changes that I will work on. More weight in the left. I have 14oz in it so far. Also I think I will work on a gifferent version of my new Tboat fin. I believe it needs more rake in the leading edge. It has been run on 3 different boats with the same results. Also go to try and set up the rudder some so it does not effect the boat as much in left trim. I think the pipe ended up being at 11.75 or so when we where done.

Now for the biggest secrect of all. Boat was designed by my good friend Russ Nachtweih. The boat runs awesome down the shute and in the corners. Like it is on rails. Without the ride of the boat it would of not been possible. Thanks Russ. Cant wait till the fall 2 laps to come so we can push the boat more. Should have a good handle of it by that time.

Mike
Good run Mike .... few of us are in the hunt for the 2 lap and 6 lap TB records this year.
 
Mike,

How much center of blade pitch was in the 6520/3?

Reduce the blade area a little more and that will

Help the boat pull off the corners better.

Keep Testing,

Mark Sholund
 
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2614/2 is a good prop.Also a H 31 will work.I ran my Lauterbach it liked the 2614/2 ran in the 50 mph range handled great.Stock zenoah
 

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