[BigBone]

I wonder how much variation there is in motor mounting in what is, essentially the same hull:

What is the height of your cavitation plates (i.e., the rear lower-most plates) relative to the stern of the hull, not the main hull bottom, but the extension that forms the running surface of the integrated transom (which is elevated about 3 inches).

My cavitation plates are definitely below the stern-most running surface, maybe 2-3 inches. I can still break the props free, but only in pretty choppy seas at speed.

1998 Contender 25
225 Yami's

[don]

2002 ,27 fter,200 hpdi's, motors mounted as low as they can go almost sitting on transom ,cavitation plates 4" to 5" below running surface of the integrated bracket.It has to be real nasty and running at speed to burp the props..

[BigBone]

Thanks, Don.

Looks like yours are a bit lower than mine and your performance sounds about right. My props probably let go a little easier than yours.

1998 Contender 25
225 Yami's

[the other tom]

When on plane, you don't run on what you are thinking is the "running surface" The "real" hull bottom has a little lip, the water runs straight off that and then contacts the lower units. Your cav. plates should be a few inches above a straight edge drawn back from the real bottom. Integrated bracket helps bouyancy at low speed. There's a reason you can't mount a sounder or 'ducer on the integrated bracket and have it work at speed. There's no water touching the integrated bracket at anything above 25 knots!

[BigBone]

Other Tom,

Thanks for the info. and I hear what you're saying.

I thought that, with the running angle at speed (11 degrees or so) the trailing edge of the raised "non-running surface" would contact the water. That part appears to be submersed while under way.

1998 Contender 25
225 Yami's

[don]

yea what he said...

[bladefl]

2000 25 Contender
EFI 200's

Just walked out side and looked. With the motors trimmed all the way down the tail of the cavation plate appears to be about 3-4 inches lower then the bottom of the stepped up extension hull. Don't know what is refered to, but the smaller plate just above the cavation plate thats leading edge is rounded and sticks out about 1-2 inches from the actual lower unit is almost even with the edge of the stepped extension hull.

With this set up I have had no problems with blowing out in rough water. They will slip alittle if I have them trimmed up to where they would be paralel with the hull or ground in rougher water. This is turning a factory set up 21p 3-blade. Also, the motors are mounted in the second to lowest holes on the mounts Hope this helps.

[BigBone]

Bladefl,

Good description. That's exactly where I am.

I wonder if the best height would be any different with 225's (which I have: more weight astern) or with the wedges many 'tender owners use. Curious as usual.

Thanks.

1998 Contender 25
225 Yami's