PH15 Sponson and engine clearance

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stickystuff
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PH15 Sponson and engine clearance

Post by stickystuff » Fri Mar 25, 2005 3:28 am

Houston, we may have a problem here.Just for the H-ll of it last night I hung my old 18 horse Evinrude on the transom. Found out that when you turn the engine it hits the sides of the sponsons.Not good. Then I checked the depth of my 90 Mariner on my PH16 and figured with a jack plate with a 4" setback and the 5' setback on the engine it may clear. I am very concerned with the prop hitting the sides of the sponson when turning the engine. Doc was here when we did this. Ye gads, I hope I dont have to cut sides and make wider. Whatcha think there Jacques? :help:


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JimW
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Post by JimW » Fri Mar 25, 2005 7:27 am

Tunnel and sponsons means sponson bottoms are deeper than the cavitation plate. Scooby says "Ruh-Roh!" I will defer to the master of course but a sponson trimming or tapering seems in order if setback jack plate won't cover it. Also, many motors will work fine with less steering. Maybe there's a way to adjust the steering limits to prevent any collisions? Maybe even with user engineering devices? Motor cowling bumpers? :idea:
Jim Wright
CC, D15, SC16, C19

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jacquesmm
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Post by jacquesmm » Fri Mar 25, 2005 9:24 am

The boat is designed for an engine mounted on a jackplate. I took in account a 6" setback. That is a standard setback, some go as far as 12". The 6" moves the engine far aft enough to allow good turning radius.
An engine mounted directly on the transom will not turn much. It needs at least 3 to 4" setback.
If you already have a 4" jackplate, check how much you can turn keeping a 1" clearance.
It only limits maneuverability at slow speed, you can go close.
You may have to limit the travel of the steering tube: a sleeve over each side will do.
With a 6" or more jackplate, you should have all the clearance you want.
Another thing to consider if you already have the 4" setback jackplate, is to use a setback spacer. A 2" one cost around $ 50.00.
There is no reason to think of cutting the sides. :)
In all cases, I would try to get as much setback as possible for the prop to run in clean undisturbed water.
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BilltheCat
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Post by BilltheCat » Fri Mar 25, 2005 11:06 am

Ken - sorry, but I'm going to state the obvious.

Low speed manuverability is real important for a flats boat - Bill the Cat doesn't have the prop problem, but the sponsons do limit low rpm/speed movement.

Best advice from me, get a 6-inch jack plate - Bob's Machine Shop - 6" for 37lbs - 10 for 42lbs

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Post by Chalk » Mon Mar 28, 2005 7:28 pm

Sound like a serious problem...I'll give you 100 bucks and take it off your hands....You got my number, call me :lol:

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Post by jacquesmm » Mon Mar 28, 2005 7:49 pm

Chalk wrote:Sound like a serious problem...I'll give you 100 bucks and take it off your hands....You got my number, call me :lol:
Read my post: with an engine mounted on a jackplate as designed, there is no problem.
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Post by AdamG » Mon Mar 28, 2005 8:35 pm

I suspect that last comment was dripping with optimistic sarcasm...

Yah...move the outboard back, you're fine...too far would be bad too though,..

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Chalk
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Post by Chalk » Tue Mar 29, 2005 7:20 am

It was a joke Jacques....

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Post by jacquesmm » Tue Mar 29, 2005 4:28 pm

I must have been in a bad mood . . . sorry.
:?
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Mike Adams
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Post by Mike Adams » Tue Mar 29, 2005 7:42 pm

jacquesmm wrote:I must have been in a bad mood . . . sorry.
:?
Didn't have a hangover from the Aussie beer I left with you yesterday, didja Jacques? :lol: :lol:
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