how do you know if you have................

[specboatops]

.........to much or not enough set back:confused::confused:

I have added some set back to my 70 G.W. Invader but hard to tell if it really made a difference, It does run flatter threw the water so I suppose thats a good thing but how do you really know?

I have 6 inches of set back on my Gambler and I tried more at 1 time it just didn't seem to want to fly the boat when I did, maybe at that time the motor needed to be higher..$hit I don't know. Is there a measure for this? or what have you guy's done in the past to determine to add or remove setback?

Chris

[Hippie459MN]

I would like to know this also. What is a good way to determine how much set back you should use so you don't end up buying 2 or 3 plates before finding the one you need.

[Raceman]

I would have said that flatter through the water was just opposite of what more setback would yield. My experience with SB is that some boats become more flighty. In the case of my STV's they had a tendency to have worse mid range porpoise when setback was added.

(see there Chris, I always respond to your posts when I see em.;):smiletest:)

[specboatops]

I would have said that flatter through the water was just opposite of what more setback would yield. My experience with SB is that some boats become more flighty. In the case of my STV's they had a tendency to have worse mid range porpoise when setback was added.

(see there Chris, I always respond to your posts when I see em.;):smiletest:)

That you do ;)

On the older 70 stuff(hulls) set back hadn't really been introduced, do you think it is effective on those older hulls ?? Or is it better just to leave it bolted right to the transom??

Chris

[bigbore]

On the gw by raising the motor already right?u set up now's probably good,tryin more would'nt hurt though.u also gotta b carefull of transom weight though,more set-back's gonna sink it more (in the a$$.):cool:

[specboatops]

On the gw by raising the motor already right?u set up now's probably good,tryin more would'nt hurt though.u also gotta b carefull of transom weight though,more set-back's gonna sink it more (in the a$$.):cool:

And it does do that. Thinking of going a lil higher too. Need to get water pressure hooked up FIRST before CABOOM :eek::eek:

[Jay Smith]

I've always thought of a boat as a see-saw .. The more set back you add the lighter the bow becomes and the less positive trim the hull requires to run clean ...If a hull seem bow heavy and requires allot of engine trim its too close to the transom ( CG too far forward ) and needs more set back. I found that in my hulls that I raced that the optimal set up was that the boat would run its fastest MPH and ET better when the motor was tucked under about 1 degree at WOT and the hull was running flat BUT with nothing but air under the hull. If a set up needs to be corrected to run clean the optimal is done with moving the Center of Gravity NOT the engine trim angle...It all about MATHMATICS...

My .02

[stokernick]

what Jay said,BALANCE,BALANCE,BALANCE!

[transomstand]

http://i221.photobucket.com/albums/dd58/transomstand/PIVOTcopy.jpg

I'm too stupid to figure out CG. I think through my butt, or what it feels:D

Agreed on the seesaw effect, and the ideal setup would put your "fulcrum", or maximum hydrodynamic pressure, at the rear edge of the pad (green arrow). Fulcrum at the yellow arrow, boat won't fly as well, and the engine will find it difficult to "lever" the boat up. Move the fulcrum to the red arrow, the hull has nowhere to "push" down on, you lose your fulcrum, all it wants to do is drive the pad deeper in the water when you add positive trim.

When you move to the red arrow area, the boat runs flatter, adding positive trim won't raise the nose much, and makes the boat unstable, it forces you to run less positive trim. This may be actually better in some applications, such as a flighty boat like mine, in terms of driveability.

Pete

[specboatops]

Pete,

I'm with you on the feeling it in my pants thing. Unless I can see it go by or watch a video of it I find it very difficult. I had a thread on here a while back on being faster when the boat was heavier, or when I had a full tank (50 gal if you can believe that in my Gambler) thaqn when I only had say 5-8 gallons.
I was losing around 4-5 mph :confused::confused:WTF I would think. So in that case I'm wondering if I need to go back further as when there is less weight it can't push the back down to get the nose up to " fly" properly and I end up plowing threw the water more............................

[transomstand]

Adding 2" setback and a heavier engine to mine made it feel like it pushes water like a bulldozer. The boat runs much deeper in the water, and doesn't have that light feel it always had.

[specboatops]

Adding 2" setback and a heavier engine to mine made it feel like it pushes water like a bulldozer. The boat runs much deeper in the water, and doesn't have that light feel it always had.

Pete,

You may want to ditch the extra set back on yours( or try) My Gambler did the same thing, I got rid of the " extra" and raised a tad and boat really came back.

there is a local guy with the same boat as you running in our neck of the woods, has a v6 of some sort( Mercury....of course) and a speedmaster gear case...............boat looks and runs quite well.
After seeing his boat the first time that is why I have bugged you about selling yours.......................Man I love the old school stuff good lines and they look tuff............

[MN4V]

Here are two photos of old school setbacks from 1972. Made by Jim Smith here in Illinois.
http://i299.photobucket.com/albums/mm315/MN392/CottonPickerBW.jpg
http://i299.photobucket.com/albums/mm315/MN392/CottonPicker2.jpg
Mark N

[transomstand]

I'm probably going in the direction of a lighter engine package. Nobody makes a jack plate with less setback than what I'm using.
Don't get me wrong, it drives very well as it is, so well, that it's almost boring. It was more fun hanging it out on the ragged edge:cool:

[Riverratt]

I have found that moving the sheep around I can find the optimum setup

[specboatops]

I'm probably going in the direction of a lighter engine package. Nobody makes a jack plate with less setback than what I'm using.
Don't get me wrong, it drives very well as it is, so well, that it's almost boring. It was more fun hanging it out on the ragged edge:cool:

HAve you ever tried it right to the transom with no set back and played with engine height? Your boat allready carries the nose well ( like I need to tell you that) I spent 1 summer pucking around with up-down- back -in-back further. I think I'm real close on the Invader, the Gambler is a different story. Just did a gearcase from Titus, so need to wait till it warms up to try from there. I've always been a firm believer in set-up set-up set-up. Wish I had more time for the dialing in. Actually wish they were both just dialed in great and I could just go out and enjoy:thumbsup::cheers::cheers:

Or maybe its time to liquidate 1 or both and go after something a tad faster
I've been swearing for years that I wanted to go with a Stoker or Ally GS.....

[transomstand]

Ran my first V-6 against the transom for about 20 years. It had the early 2 ram clamp which only had a single set of holes, the only option for moving the engine would be drilling more holes:nonod:. The engine needs to be about 6" (or more) above the transom, I thought an extension would be too ugly. I'm thinking about a 15" mid, but with a modified clamp (factory clamps have 2" setback built in), would also require a factory offshore can, which brings in the overweight problem again.

My life is just filled with setup difficulties:eek::D:D

[specboatops]

Ran my first V-6 against the transom for about 20 years. It had the early 2 ram clamp which only had a single set of holes, the only option for moving the engine would be drilling more holes:nonod:. The engine needs to be about 6" (or more) above the transom, I thought an extension would be too ugly. I'm thinking about a 15" mid, but with a modified clamp (factory clamps have 2" setback built in), would also require a factory offshore can, which brings in the overweight problem again.

My life is just filled with setup difficulties:eek::D:D

.....But think of the knowledge on your particular boat that you have now:thumbsup:

For myself I figure sooner or later I have to be willing to accept that there is only so much I will be able to do with what I have.........thats the hard part.

[transomstand]

.....But think of the knowledge on your particular boat that you have now:thumbsup:


If I could only remember what I know:eek:


For myself I figure sooner or later I have to be willing to accept that there is only so much I will be able to do with what I have.........thats the hard part

That's really the decision we have, do we own the right boat? I could easily get mine in the mid 90's, but then you start to deal with the "terminal" hull speed issue. If I need to go 100 that bad, just buy a Euro and make it easy.

[specboatops]

Here are two photos of old school setbacks from 1972. Made by Jim Smith here in Illinois.
http://i299.photobucket.com/albums/mm315/MN392/CottonPickerBW.jpg
http://i299.photobucket.com/albums/mm315/MN392/CottonPicker2.jpg
Mark N

WOW that looks just like the jack plate on my Invader.........Feel even better now that I kept it old school;)

[Denny <><]

I have found that moving the sheep around I can find the optimum setup

Now thats some funny stuff right there. LMAO

[bigbore]

God da## comedian,bigbore still scared.:cool::thumbsup::cool: