Setback Question

[Esox]

How do you know when you have too much setback? Is there anything specific look for that would indicate the engine is too far back? Thanks

 

[Esox]

Re: Setback Question

^^^^^^^^^^

Anybody have any input on this?

 

[Iam74Gibson]

Re: Setback Question

I am no expert, but my boat rep told me when I bought my jackplate that if I went with more than a 6 inch setback, my boat would porpoise alot (rise and fall of bow while running) I would also think it may make the bow harder to trim down, since a lot of weight is in the back.

 

[Dhadley]

Re: Setback Question

Yes, the handling and performance will fall off. Walleyehed had some first hand experience on this. Perhaps he'll pop in.

 

[Esox]

Re: Setback Question

Thanks for the replies. I put on a bobs 4 in 1 and tested it with 5" of setback. It made a big difference in the overall performance (although it could still use more bow lift). The only problem now is the steering cylinder is in line with the transom so I have to raise the plate way up to be able to tilt the engine up. The way I see it is I have 2 options. Widen the notch in the transom or move the engine back more with the 2" spacers. Guess I'll get the spacers and do some more testing. If 7" turns out to be too much I'm looking at cutting into the transom

 

[Dhadley]

Re: Setback Question

Sounds like the motor is too low. When you go back you can raise the motor about 1" for every 5" you go back. If the motor was too low to start with you may be way low now. When the AV plate is parallel is it even with the keel or up some? How much up?

What hull? What prop?

Bow lift can come from setback as well as prop design.

 

[Esox]

Re: Setback Question

It's a heavy 18' Deep Vee aluminum - 150 Johnson. I have a 19"p Ballistic and a 19"p Turbo 1 (I need to see if I can exchange the T1 for a Lightning). Maybe this will shed some more light on my setup:​

http://forums.iboats.com/showthread.php?t=178293​

With the engine mounted to the transom I was in the top hole (2.25" up from keel) After the 5" setback best performence was with the engine 3" above the keel.​

 

[Esox]

Re: Setback Question

was with the engine 3" above the keel.​

Sorry - that should read A/V plate​

 

[Esox]

Re: Setback Question

Sounds like the motor is too low.

I just realized why you said that. Like a light bulb went off ​

Here is a pic of the transom.​

 

[Dhadley]

Re: Setback Question

Yep. Let the plate down and raise the motor on the plate. that should give you enough clearance to tilt it and keep the AV plate at the same place.

 

[Esox]

Re: Setback Question

I guess I should have added that the engine is up 1/2" higher (A/V plate 3.5" up from keel) in that picture. I'll give that a try and see what happens. Thanks "Dr. H" Your help is greatly appreciated.​