Stock Shaft Down Angle

[JohnV8r]

Hey Guys,

Anyone know what the stock down angle on the 1 3/8” shafts & struts is? I’m not at the boat and need a quick approximation.

Thanks,

JohnV8r

[Ironworker]

Not 100% sure but I think its 15 degrees.

[JohnV8r]

Thank you!

[Ironworker]

Don't take that to the bank. Somebody who actually knows what they are talking about likely will come along shortly.

[Tony Meola]

John

What year is your boat? I don't remember the year but at one time some of them had 12-degree shafts.

[Tony Meola]

John

I found this from an old 2020 post. Maybe Carl can confirm since he was the one who stated the 10 degrees.

the 31. The stock 10-degree struts from what I know are for 1-1/4" dia shafts with no room to bore open for larger bearings. Then they only have ... point just yet. What I can say for sure...the closer the shaft/prop angle to the direction of travel the more efficient the setup. Outboards ...

[JohnV8r]

1978 FBC. 1 3/8” shafts.

[Carl]

Older boats running 1:1 trans on gas motors with 1-1/4 shafts had short, sleek 10 degree struts allowing a 15inch wheel. These struts had no beef to open for larger shafts.

The others had the longer 15 deg struts allowing the boat to turn a more efficient larger diameter wheel. These came through with 1-3/8" shafts to handle the extra torque. The barrel holding the Cutless was also kinda beefy so most struts could be machined open a bit to fit a larger Cutless bearing opening the door for 1-1/2" shafts.



If your not sure...your wheel size will tell you. A 16" diameter wheel left a prop tip to hull clearance of aprox 3/4", so if your running a larger wheel, it's not the 10 degree strut.

[Snipe]

John mine is 1977 and stock was 15.2deg with 1 3/8” shafts

[Tony Meola]

John

You would have the 15 degree shaft angle.