Any Ideas?

Dry Run · 18 May 2011, 10:50

One of my Dryt Stack customers has recently re-engined their Avon 620 (the hull with the fins that poke down) and have changed from a Yamaha 115 to a "counter rotating" Suzuki 150 (don't ask!!!). They now say that they are experiencing a definite "tilt" to the Rib when under power. They have altered the angle of the fin on the cavitation plate, but to no effect. They have tried putting ballast to one side of the boat, but this needs at least 100kg to correct and will play havoc with the fuel consumption. He's considering moving the engine but only has about an inch and a half on the transome to play with. He's also been considering trim tabs. So, before he embarks on any wild and expensive fixes; what do you guys think? I'm sure it's been discussed before, but any new ideas would be welcome.

Mollers · 18 May 2011, 11:01

Offset.

Kernow Buoy · 18 May 2011, 11:12

Quote:

Originally Posted by Mollers

Offset.

or in his case Onset!

Starovich · 18 May 2011, 11:46

how about a normal rotating Yamaha 115 ?

Kernow Buoy · 18 May 2011, 11:50

Seriously, I think he's going to have to move that engine, the one and a half inches may be enough, either that or find a conventional rotating Suzuki gearbox, but you did mention expensive!

Dry Run · 18 May 2011, 11:53

Quote:

Originally Posted by Starovich

how about a normal rotating Yamaha 115 ?

I think he was quite happy with the Yam 115, but unfortunately despite claims of military quality security someone stole it from his boat while it was at a nearby "rival" dry stack (not mentioning any names)!!! Still, at least they didn't take the whole Rib.

Nasher · 18 May 2011, 12:00

I'd agree that moving the engine is probably the way to go.
Probably a inch will do.

Changing the gearbox may be a very expensive way to move the tilt the other way.

Nasher.

Dry Run · 18 May 2011, 12:51

Thanks for the comments. I think we'll go with an engine move as it's relatively easy. If it works, I'll let you all know.

C-NUMB · 18 May 2011, 13:05

How about different prop, that also might change something, test 4 blade or otherwise differrent?

bedajim · 18 May 2011, 14:27

Ask Hightower, he's more up on this sort of thing

Hightower · 18 May 2011, 16:41

Quote:

Originally Posted by bedajim

Ask Hightower, he's more up on this sort of thing

Funny you should mention that.......Here I am!

I have a CCW 150 mounted on a 6.2m Vipermax. 11/4" - 11/2" from the center line to port side will be about spot on.

If he wants to sell the 150, let me know?

Dry Run · 19 May 2011, 08:03

Thanks to everyone for their help and Hightower for the specialist advice. Will move it in the next few days and let you know if it works. I have a few different props, so might play around with those just to see if it makes any difference. Cheers again!

Cookee · 19 May 2011, 12:22

Ask him if it makes a difference when trimming it out - I think he'll find that with a bit of trim the problem will disappear!

Dry Run · 19 May 2011, 18:10

Cheers, might ask him about the "trim out" thing

kubcat · 16 July 2011, 09:16

Quote:

Originally Posted by Dry Run

Thanks to everyone for their help and Hightower for the specialist advice. Will move it in the next few days and let you know if it works. I have a few different props, so might play around with those just to see if it makes any difference. Cheers again!

Any feedback yet?

Dry Run · 16 July 2011, 10:25

Thanks to everyone for their help. I'm pleased to report tha we moved the engine and guess what? It worked!!!! Boat is now perfectly balanced! Cheers again.

Hightower · 16 July 2011, 15:20

Glad we could help.