BajaNomad

Bolt-On Anti-Cavitation Plates

kitjv - 7-1-2007 at 09:13 AM

Realistically, are there any significant benefits to adding a bolt-on anti-cavitation plate to a Honda 20HP outboard used on a 12-ft. inflatable boat? If so, why don't outboard manufacturers design their motors accordingly>

Thank you for your thoughts.

Hook - 7-1-2007 at 09:20 AM

I have used them on smaller o/bs or lighter boats and I think they make a significant difference. They might cost you a mph or two off the top end but they make up for it in quicker planing and more efficient operation at low-mid speeds.

comitan - 7-1-2007 at 09:36 AM

I have made and used them for years, the reason I make my own is that the ones you buy are not large enough or long enough. On your short boat they would make a big difference, you would plane faster and be able to hold onto a plane at a slower speed.

[Edited on 7-1-2007 by comitan]

DSC00992.JPG - 47kB

Bob and Susan - 7-1-2007 at 10:35 AM

under 90 hp they work great

over 90 hp not needed

vandenberg - 7-1-2007 at 11:40 AM

Quote:
Originally posted by comitan
I have made and used them for years, the reason I make my own is that the ones you buy are not large enough or long enough. On your short boat they would make a big difference, you would plane faster and be able to hold onto a plane at a slower speed.

[Edited on 7-1-2007 by comitan]


Wiley,
What material did you use? Maybe another picture or two. Have a 75 without one ,but I know they make a difference.

comitan - 7-1-2007 at 12:19 PM

The material is aluminum 3/16 I believe, I do have one I made for my 18' Seaswirl with 140HP IO that was to small, its probably to wide a cutout in the center for an OB even the seaswirl will plane faster and keep a plane at a very low RPM. The ones I have all look alike just different in size.

Kit...U2U me, I have a set for sale that will fit your 20 HP.

vgabndo - 7-1-2007 at 08:32 PM

Plastic "whale tail" type. Worked great on my 10 HP Honda, and a 25 Johnson.

BajaBruno - 7-2-2007 at 10:50 PM

KitJV,

I don't know how a 12' inflatable could handle the transom weight of a 20HP Honda. I tried it on mine and the transom nearly bent over. It worked great with a 20HP 2-stroke, and a 10HP Honda, but the 20 HP 4-stroke was way too heavy

Also, I can't see why a 12' inflatable would need any help from a plate with 20HP behind it. That's just about max power for a 12' and it should plane easily, even with several adults aboard. With a 10HP Honda, you might want some assist.

kitjv - 7-3-2007 at 06:35 AM

BajaBruno,

Thanks for the info. The Honda 20HP 4-stroke weighs 105 lbs. The maximum rated HP for the boat is 30HP with a transom weight of about 175 lbs. Admittedly, I haven't set off on my maiden voyage yet, but I am not anticipating any problems.

I will run the boat without the stabilizer plate first. Then, possibly, install the plate for comparison.

Barry A. - 7-3-2007 at 06:39 AM

BajaBruno-----------my friend uses a very old Mercury 35 2-stroke on the back of his 12 foot Avon inflatable and it is a "rocket". He has no problems with the weight. He does not use a anti-cavitation plate. He does carrfully moderate the throttle, tho. :lol: