FS14 Motor Shaft Length

Boats up to 15' for oars, power or sail. Please include the boat type in your question.
cdurbin
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FS14 Motor Shaft Length

Post by cdurbin »

Looking to answer whether I should order the short (15") or long (20") Yamaha F20 for my FS14.

Looks like S shaft is 17.4" from transom mount to cavitation plate

Looks like L shaft is 22.2 in same dimensions

From plans, I see 19 ⅝" on this dimension transom to keel. So I am thinking I need the F20LWB (long shaft). Anyone running a Yamaha on a FS14 or have thoughts?

jacquesmm
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Re: FS14 Motor Shaft Length

Post by jacquesmm »

You can adapt almost any of my designs to the shafts length of your choice. See the tutorial I wrote about that in the How To section. In most cases, I prefer a long shafts. Go for the 20 inches shaft.
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bklake
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Re: FS14 Motor Shaft Length

Post by bklake »

20". 5 more inches keeping water on the correct side of the boat.

My Carolina Skiff has a 19 3/4" transom. My motor measures a little over 21 inches. It is too deep in the water. Slows it down and causes water to splash back into boat. I had to make a 2" block to raise it and drill another set of holes in the transom. You would think a production boat would be able to match the shaft length of most motors and you would think that motor companies could make a 20" shaft that is actually 20". Not so.

Either make your transom tall and cut it down to the correct height once you have your motor or get your motor first and make your transom to fit the motor. Don't forget the trigonometry of the transom angle. I suck at math but I do know how to put a straight edge on the bottom and put the cavitation plate just below that.

TomW1
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Re: FS14 Motor Shaft Length

Post by TomW1 »

Yep always get the long shaft. If it is really 22" and not 20" make and adjustment to the height of the transom, so you are not dragging the lower unit through the water. You want the center of the prop even at the bottom of the boat,
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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