posted 06-03-2003 11:34 PM ET (US)            

Mine was about 1/4" below, I raised it one hole so it is 1/2" higher and noticed a stark change in ride. I am going to go up another hole and see what happens. I think it will be better.

posted 06-03-2003 11:51 PM ET (US)            

However they did not listen. I have about 3" of upward travel left in my jackplate, do you guys think I have enough travel left to raise my engine as high as I would ever want to go. Also they redrilled the bottom hole on the jackplate so that the botom hole is now about and 1" higher, so I no longer have a standard pattern. Some people just do not listen. Anyway I hope they have not screwed my boat up.

You guys that have experience with jackplates let me know what you think.

posted 06-04-2003 10:24 AM ET (US)            

Do you think I will have enough height left with 3" of upward travel still left to raise my engine enough for best performance. I can lift the engine up one or two more holes as well. Again they have the jackplate adjusted up about 1/2" and the CP is about 1/2 above the keel. What do you think?

posted 06-04-2003 12:14 PM ET (US)         

Engine mounting height, which usually translates to the height the anti-VENTILATION plate runs above the surface of flow coming off the hull bottom, can only be so high, based on keeping the engine's water intakes submerged, and to not take in air. This dimension is easy to measure on your engine. For most, it is no more than 3", nor would you want more than that except for an all out racing application.

Since Whalers are not high performance nor racing boats, for most applications the optimum range would be 3/4" - 2" max. For twin engine installations, a little less, since each prop is cutting the water off a sloping Vee, rather than the bottom of a Vee.
The inward side of the prop is, in effect, running much higher than the outward side.

If you are elevated 3/4", as was recommended by Whaler, a standard cupped aluminum or SS "elephant ear" prop will suffice, as long as your top speed doesn't exceed 40 mph or so. My own expeience on Whalers is that aluminum props are strictly bottom of the line, and don't perform very well over 30 MPH when compared to an SS. For the 30-40 MPH top speed range, a standard SS is usually fine, engine in the second bolt hole pattern .

It's when your boat is capable of 40mph or better that you should be looking into a "performance grade", higher rake, vented, surfacing capable, SS prop, and get your engine up another bolt hole to 1 1/2". These will perform at elevated transom heights, such as 1 1/2" or 2" max, and the tips will "surface pierce" the water at high running speeds, with no slippage. For almost any Whaler, up to 65MPH speeds, 1 1/2" is about all the height you need for good performance in all conditions. For really high running heights of 2" - 3", really only recommend when WOT top speed is the only objective, a prop like the Mercury 4-bladed Trophy Plus or Tempest is called for.

Unless the engine is mounted directly on the transom, visually sighting the anti-ventilation plate against the hull bottom doesn't work. With setback brackets of any kind, you actually have to look at the flow coming past the engine to see where you need to be. Setback engines can always run higher RELATIVE TO THE TRANSOM, because the water flow immediately begins to swell back up once the boat passes through it. The further back the engine is, the higher the swell rises back up. Because they are higher, they can run faster with less gear case drag resistance. On my 25 Outrage, with 26" setback Armstrong bracket, sighting against the transom, the engines appear to be up about 4", but actually are only about 1" high at the water flow past the engines themselves. So the water is swelling up the other 3" as the boat passes through it.

posted 06-04-2003 04:49 PM ET (US)            

I have an '87 Montauk with a 2001 90 hp Johnson. From everything I've read here I've deduced that I need to raise the motor. Currentley it's mounted all the way down, touching the top of the transom. Upper bolts are in the top holes which is no big deal to change, but the lower bolts screw into a blind mounting on the motor mount. The motor has mounting slots below the blind holes, but they seem to be a fair distance down.

My question is; Since this seems to be a common set-up for '80's vintage Montauks with OMC 90's, has anyone raised thir motor high enough to use the lower slots instead of the blind holes? And if so, what were the results?

At some point I will install a set back bracket, but for now I just want to raise the motor.

posted 06-18-2003 10:49 PM ET (US)            

Whaler recommends that the AV plate be 0-3/4" above the bottom of the boat. Seems that the consensus on CW has been that 3/4" to 1.5" is the place to be.

I'm moving mine tomorrow nite - currently within Whaler's recommendation (one hole up from bottom) putting it at 1/2" above bottom. I'll post results assuming I get this done tomorrow.

posted 06-19-2003 08:22 AM ET (US)            

And I quote: "Increasing the height of outboard generally will provide the following: 1) Less steering torque, 2) more top speed, 3) greater boat stability, but, 4) will cause more prop "break loose" which may be particularly noticeable when planing off or with heavy load". End quote.

Source; installation manual, 115hp (4-Stroke) Mercury Marine, copy right 2001.

posted 06-19-2003 10:59 PM ET (US)            

Side rooster tails are gone, boat has better trim range and she goes better through boat wakes (calm nite tonite). I'll do more testing later but it looks like I picked up about 200 rpm and about 2mph, motor doesn't sound like it dogs at full down trim. The whole thing just feels better, she goes better through the water in general.

The ride seems much better. When motor (75HP FICHT Evinrude) was put on the boat, it was all the way down. Terrible pounding ride. Picked it up one hole, improved it alot. Went the rest of the way tonite, worked fine. No prop blowout, motor pees water fine.

I still don't have the trim range that I want. Talking to Stilleto prop guys based on Sal's comments about them, I'm going to order a new prop and put that on too.

I used the jacking the trailer tongue method of moving the motor up. I put the trailer tongue on the pavement and strapped the boat to the trailer, removed the top bolts then loosened the bottom sliders. jacking the tongue up moves the motor up on the transom. Insert bolts when they are where you want them and your done. Whole thing from start to finish took about 45 minutes in the parking lot at the ramp.

Easy experiment, go for it if you have any doubts at all. I think its likely that you will like the result.

j

posted 06-20-2003 08:55 PM ET (US)            

Raising the is relatively easy to do and has a big effect. Between the two of them, you are talking a one hour project.

My personal preference for fins is the Grand Island Turbo Lift. You don't need to drill the AV plate, it is stainless steel and I found better results with it than with a Stingray (on a different motor). YMMV.

posted 06-23-2003 05:11 PM ET (US)            

Each unit is specific to each motor so you need to get the specific one that meets your motor's dimensions. It is made out of stainless and it is bullet proof (maybe literally).

They don't have a website since most of what they sell is OEM and goverment (US Customs and USCG boats is my understanding). However they will sell to you directly.

This was recommended to me by Chuck B. at Whaler. He said that they have used them in a number of applications with great results. This is how I heard about them.