The Question is

[JamesM]

I use a 22 small hub laser 2 but its been worked to a 22.5 with some cupping and thinning.

I would have ago at re-bleeing the steering you should be able to get the play down to about 1mm. If you using a front mount cylinder attached to the tiller arm then the play at the prop will be about twice as much as at the cylinder. So thats 6mm down to 2mm.

[Ciao]

Originally posted by Johnny Boat Dude
I use a 22 small hub laser 2 but its been worked to a 22.5 with some cupping and thinning.

I would have ago at re-bleeing the steering you should be able to get the play down to about 1mm. If you using a front mount cylinder attached to the tiller arm then the play at the prop will be about twice as much as at the cylinder. So thats 6mm down to 2mm.

May be interesting to tell him what revs you pull with your Laser and top speed

[JamesM]

I've seen 6750RPM down a nice flat river. But out at sea 6600 is typical. thats with 1.87:1 gears. 5.5" of set back with the prop shaft about 2 1/2 inches below the bottom of the boat. I reckon thats about 70mph.

[Jon Fuller]

it's a long time since I played with this type of setup, but I would have thought that when the motor is flat out, on flat water (as with this case) a bit of slop here and there' wouldn't make any difference, coz the whole thing will be well & truly 'wound up', that is, motor and all components will be pushed fkkn hard 'one way' with the paddle wheel effect, and there wouldn't be any chance for it to wobble about, way too much pre-load to st/bd.

Now running offshore would be a different case entirely, but he aint.

So I reckon it's a set-up ussue rather than a fault like sloppy bushes, or steering.

Just MHO tho'.

jf

[Jon Fuller]

Originally posted by Johnny Boat Dude
I've seen 6750RPM down a nice flat river. But out at sea 6600 is typical. thats with 1.87:1 gears. 5.5" of set back with the prop shaft about 2 1/2 inches below the bottom of the boat. I reckon thats about 70mph.

The Yamie's a lower revving motor tho', innit, and I don't know what the gear ratio is.

My initial reaction is, a P20 with a 200, set up nice, with the motor bolted straight on the transom, would get pretty close to 70, mebbe more, so yet again, what's all the fascination with set back?....all a bit 'Gucci' I reckon, mebbe less so with this case, as he's using it purely on flat water, but with our boys in the salt.??

[JamesM]

Whilst on the subject of bushes and steering play, you should check out the motor on the back of Cyes Bernico, its like the sword in the feckin stone. The only person that can move it is the man in the drivers seat

[Jon Fuller]

Originally posted by Johnny Boat Dude
Whilst on the subject of bushes and steering play, you should check out the motor on the back of Cyes Bernico, its like the sword in the feckin stone. The only person that can move it is the man in the drivers seat

Quite scarey that, given the person who sometimes occupies that seat

[JamesM]

Originally posted by Johnny Boat Dude
Whilst on the subject of bushes and steering play, you should check out the motor on the back of Cyes Bernico, its like the sword in the feckin stone. The only person that can move it is the man in the drivers seat

I have set back on my white P20 cause its a hydraulic stainless CMC jobbie and its a bit tasty

And on the Red one cause it was on there when I bought it and taking it off would mean the steering cables would be to long and come out in the wrong place. Also it goes well with it on there and I can easily play about with the engine height (manual CMC lift).

[JamesM]

oops seems I quoted the wrong person!!!

[Phantom20]

...my Yammie doesn't have a rev limiter.... :o)
the gearratio is 1,85:1
I reached befor restauration at 6000rpm 70mph with 400mm setback for some seconds due to chinewalking....

now the engine is on middle of transom same setback much better steering and solid mounts I can only reach 65mph due to chine walking....

there must be a way to run these setup fast....

[JamesM]

Originally posted by Johnson
The Yamie's a lower revving motor tho', innit, and I don't know what the gear ratio is.

My initial reaction is, a P20 with a 200, set up nice, with the motor bolted straight on the transom, would get pretty close to 70, mebbe more, so yet again, what's all the fascination with set back?....all a bit 'Gucci' I reckon, mebbe less so with this case, as he's using it purely on flat water, but with our boys in the salt.??

Should have been this one!!!

[Burty]

Originally posted by Johnson
Quite scarey that, given the person who sometimes occupies that seat

I hope you wern't refering to me dude

[JamesM]

You could try getting someone to sit on the back seat and then move from one side to the other whist going along and see if at any time/positon it cures the chine walking. If this works make note of there positon and then move all the heavy objects battery trim pump etc to this location.

Only trouble is if you then get passenger in the boat it may well upset this balance again.

[Jon Fuller]

Originally posted by Burty
I hope you wern't refering to me dude

[Ciao]

Originally posted by Phantom20
...my Yammie doesn't have a rev limiter.... :o)
the gearratio is 1,85:1
I reached befor restauration at 6000rpm 70mph with 400mm setback for some seconds due to chinewalking....

now the engine is on middle of transom same setback much better steering and solid mounts I can only reach 65mph due to chine walking....

there must be a way to run these setup fast....

have you tried anothe prop ie 3 blade cleaver ? I have know phantoms to chine but as you increase speed you can drive thru the problem..maybe your prop isnt giving you that chance.

[BluFin]

I cant say how to get the most from your P20 top end I can only say some general set up points.
Firstly when it all goes wrong go back to basics or a know working configeration & start again.
Put the motor back on the tansom- or reduce the set back I think that may have a lot to do with it.
Change only one thing at a time and make written notes dont trust your memory.
make a change and see what it does. VArios types of prop will have a huge effect. Try carrying some ballast and move it about the boat see what it does. A person with no fear is ideal have them move about then try it with a run, go to another point & another run.
An old thing that used to be done to prevent this was to fit a shark fin on the underside of the hull just 2" or so. made things more stable a lot of the small don sghead boats did this. It works

The 21, Howie & I set up wasn't the fastest but the best handling & most reliable. as mentioned on another thread we did win the championship that year and by mid season. thnk it might still be a recored in terms of the time it took to win it was over before august & was the last 21 to win a c'ship so someone mentioned.
Trust your own judement, but again only one thing at a time. personally I'm into offseting engines others arn't others like lots of setbacck & lift . It's all a variable.
Everybody will have different ideas and we will all waste hours playing around at the end of the day thats part of the fun.
If you were looking for top speed and you are boating on the Rhein think about a cat. but life is full of trade offs.

[BluFin]

Burty & others have obtained much better speeds from their ones tha we ever did. They will have a lot of advice & tips to offer. All very valid points. But everbody drives differently & prefers different styles. It's quite customised really. If you want handling then I can chip in if you want top end. I ant so good on a 20.

[Lars T]

Wouldn't a set of nice trim tabs eliminate the chinewalking or atleast some of it..??

Oliver - have you tried at larger prop? say 25"-27"?

[Phantom20]

Hi Lars,

yes I thought about a pair of 24" long taps...but I'm sure there is a way to run stable without taps.... :-)

Yes I tryed a 4blade with 25"p..I've reached at 6000rpm 72mph but grim reaper was sitting beside me...!

[BluFin]

Originally posted by Phantom20
mph but grim reaper was sitting beside me...!

Get him to move about the boat see what difference it makes