My "wedge" as arrived. Smaller than I expected from the pictures. I guess now I've got to get to work pulling the engine. I'll try to photo-document the procedure and post it in the spirit of continuing Hydrodyners education.
Hi Guys, did you receive 3 degree or 5 degree wedges? The 3 degree ones are pretty thin. They do make a big difference. But it would be really useful for Dyne owners to know that a XXX weight motor on a YY Dyne hull works best with a certain amount of wedge. I'd love to see you try both types and report back. But then again I'd be interested to read the report on just one type if that is all that came forward E-TECs have trim limiters built in. I would expect this is because sometimes on some boats too much negative trim could be a negative... I've never seen it though...
My 18 has a 1995 Johnson Fastrike 150 on it. The motor weighs 370 and the boat is light with nothing on it that is not required to ski. Nothing fancy. I have a service manual and an operators manual and I cannot find any listing for total negative trim. It seems that the manufacturers have bragged about more negative trim available every year for the past 30 years. It should be immense by now. If the wedge is installed, it is easy to determine the performance without the wedge by limiting the negative trim to something equivalent to the angle of the wedge. If I do that there is bow rise and fall-over when the boat reaches planing speed. The planing speed in this configuration is greater than when fully trimmed in. The bow rise when pulling up a skier is greater. The wedge is 5 degrees and full down trim just prevents the hull from "freeing up" and limits the speed available. Trimming to the mid position on the gauge brings the bow up a little and reduces the wetted area and allows more speed. More trim produces a bigger rooster tail and no more speed. Extreme positive trim produces porpoising. All of the above is with an aluminum 14.5 x 17 with the cup removed. I also have a torque shift prop which has more rake and is double cupped. It tends to carry the bow a little higher, and the performance is similar except there is more speed available because it is a variable pitch prop prop that keeps the motor in it's power band. It has considerably more hole shot because it starts out at 11 inch pitch. jim
Hi Guys, Got my 17.6 with a 150 Optimax out on the water for the first time yesterday. Looks like the boys did a pretty good job rigging it. The motor is mounted one hole up on the transom and it doesn't appear that a wedge will be required. There was absolutely no bow rise out of the hole with the motor trimmed all the way down, however that was without pulling a skier. The prop is a four bladed 15" X 18p and the boat takes off like a bandit. Obviously there will have to be a lot of discretion used by the driver when there are kids in the boat!! There seems to be more engine vibration at the 2000-2500 rpm range and the throttle needs to adjusted. But over all, WOW!! More test driving today,, yippeee!! Kevin
Is it actually vibration or is it intake noise? The optis have a single large intake that has a resonance that I thought was closer to 3000 rpm, but it could be lower.
My optimax has a nasty vibration if the motor is trimmed all the way down. I'm hoping with the wedge I won't need to trim all the way down anymore. I ordered my lifting ring. Now, I just need to find 7" mounting bolts and I should be ready to go.....
That's a good idea. I just need to look at my tech specs to see what diameter and thread. I know I have it somewhere, unless someone here just happens to know.... Thanks Bob!
