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Motor setback on OB Cats...

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Old 06-08-2005, 10:46 PM
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Default Re: Motor setback on OB Cats...

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Originally Posted by X-Rated30
I am not interested in changing my boat, so much as I am with Tantrum and find it an interesting topic.

Or at least that WAS true until you said you picked up 7mph.
The 7mph had a lot to do with being able to fine tune my engine height as Shane said. Its a lot easier this way than drilling new holes in you transom. However, my speeds are now in the normal range for what my boat should run. mmwalters is also correct in that fast is relative. I am fast on a river, however in the bay I am fully aware that the setback would hinder my speed. Good topic also, always good to hear about other people with O/B Cats. Bang for the buck its hard to beat these setups!
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Old 06-08-2005, 10:55 PM
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Default Re: Motor setback on OB Cats...

Another good question? What kind of slip numbers are you guys running? I dont have that much experience with these boats either and am still learning. Maybe this is normal.....but in my boat I can hit the rev limiters with 4 people, fuel, cooler etc.. just as fast as I can with just me in the boat. The difference is the speed but rpm stays consistent. I trim the boat the same every time...Level with the bottom to get the rpms up and then slowly touch it down to negative trim.
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Old 06-09-2005, 03:21 PM
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Default Re: Motor setback on OB Cats...

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Originally Posted by mmwalters
The problem becomes, you have a fast boat that will not run in rough water.

Why would more setback hurt in rough water? As long as you don't have the motors trimmed too much it should fly thesame as long as it is still balanced (shifted some other weight forward).
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Old 06-09-2005, 11:44 PM
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Default Re: Motor setback on OB Cats...

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Why would more setback hurt in rough water? As long as you don't have the motors trimmed too much it should fly thesame as long as it is still balanced (shifted some other weight forward).
Static weight balance in very important in these boats. Race boats use water ballast tanks that can be filled and dumped while running. The goal is to have the hull fly level when leaving the water. Back in the day in APBA the prostock triple outboards and modified boats with smallblocks where mostly 32' skaters. Sometimes the 2 classes started together. The outboard boards where offten equal in speed but in any kind of rough water the inboard boats would pull away.
That said I believe a 6'' setback would present little problem on a 30' hull, maybe as much as 10'' would work depending on your hull. And adding some weight forward is an acceptable way to help balance the boat, lead shot works well. Ideally one would want the boat as light as possibile that would carry the nose with as little trim as possible and fly level in the rough. Every setup is different and only testing will reveal which setup is best for your rig. For me that is part of the fun! Also prop rotation can be a factor, but that is another discussion
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Old 06-09-2005, 11:58 PM
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Default Re: Motor setback on OB Cats...

Dreamboater With a good setup slip factors in single digits are possible and 10% would not be out of line. I had the same situation as you regarding the rev limiters on the promax. I had Rapair bump them to 6700rpm. Picked up a couple of mph so far, maybe more is left with the prop work from throttle up I have not tested yet. I will let you know

Last edited by mmwalters; 06-10-2005 at 12:01 AM.
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Old 06-10-2005, 12:06 AM
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Default Re: Motor setback on OB Cats...

You need to ask yourself where are you going to be running the boat. If you are doing alot of lake boating run the jackplates. If it is ocean boating bolt those engines to the Transom. Less top speed but better Rough water handling. I run a 24 Skater and I am running BOB's marine 3in spacers. If you are going to due jackplates I recomend CMC. Plus they are made in Oklahoma
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Old 06-10-2005, 09:01 AM
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Default Re: Motor setback on OB Cats...

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Plus they are made in Oklahoma
And to think I heard that only steers and queers came from Oklahoma.


Last edited by X-Rated30; 06-10-2005 at 10:10 AM.
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Old 06-10-2005, 10:11 AM
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Default Re: Motor setback on OB Cats...

I guess I am still a little passive aggressive about the NCAA Championship this past year.
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Old 06-10-2005, 01:59 PM
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Default Re: Motor setback on OB Cats...

A boating buddy of mine has 10 inches of set back on his 26 eliminator daytona with 300X's. His comment was that the boat runs 6 mph faster than just with jack plates ( 113 vs 107) and actually, once he moved some stuff around to rebalance it runs better in the rough now.
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Old 06-10-2005, 02:11 PM
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Default Re: Motor setback on OB Cats...

CMC makes a plate that all the offshore racers use. It has 2 1/2'' of adjustment 5 1/2'' setback and heavyduty components. That is the one to use.
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