Prop Shaft

**gn7** · 02-03-2014, 02:48 PM

Originally Posted by WESTERNAERO

V-drive pros, explain prop shaft material, diameter, couplers, nickel/shim adjustments and anything else that might educate the masses.

Bigger is better, safer and will last longer. The diameter will effect the lift of the boat as well as drag.
material is like hair color on women.
shims/nickles are crutches for strut placement. If you have to shim your shaft, it simply means you put your strut to far forward using Teague's one size fits all formula. Don't shim the shaft, don't move the strut, change the HP until its right, up or down.

If you have more power than a lawn mower, you use a steel coupler with a minimum of 5 bolts, 6 preferably if you have the room. I don't see the other side of this subject. Its like buying your shaft material off the rack at some metal supply house. They did decades ago, but we've come a little ways since the learning years. Some things are no longer intelligently debatable.

**HB Vic** · 02-18-2014, 10:52 AM

On occasion I like to play the slots, but I prefer blackjack. Oh and I prefer no fillet with my slots please

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**gn7** · 02-18-2014, 11:26 AM

Originally Posted by Hotboat

On occasion I like to play the slots, but I prefer blackjack. Oh and I prefer no fillet with my slots please

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You cruising to get banned from the v drive forums there HB?

**HotWater** · 02-22-2014, 10:27 AM

Those little set screws must take a lot of the stress off the key. I pulled a key out from a coupler that did'nt have the set screws in it and the key looked like it had been offset ground from all the load being transferred to it.

**sangerdan** · 02-22-2014, 10:58 AM

I hope I can make this understandable because I'm not good at posting pics. If you could make the I.D. of the collar a "D" shape where the flat of the "D" matched the flat on the shaft, metal to metal fit that would be better than the set screws. The set screws and flat on the shaft are as close as is economical to produce. Keys are not meant to transfer large power but are the easiest way to establish the relationship between the shaft and collar so everything mates square and in a specific location. Those set screws are less affective if they are not at 90* to the shaft flat. If that key splits and spins long enough, it will weld the whole works together, friction welding is viable process in the right place.

**HotWater** · 02-22-2014, 11:19 AM

GN7, with a split collar in front of the strut, how does the bushing get water to lube and cool? I can't imagine water being able to pass through the split at high rpm.

**gn7** · 02-22-2014, 12:43 PM

Originally Posted by HotWater

GN7, with a split collar in front of the strut, how does the bushing get water to lube and cool? I can't imagine water being able to pass through the split at high rpm.

Hasn't proven to be a problem to date. The bushings last about the same amount of time as without the collar. We usually change the bushings during the spell between the Nov opener and the next race in March. Its our longest down time and that's when we do stuff like that and blast plates, steering cables, pulley bushings etc.

It larger than a split 2 bolt safety collar. Like I said, its 4 bolts, and it tapers. Its probably about 4X as long as a regular split color. You can just see it in front of the strut in this picture. Its actually rule in GN. Some are just stouter than others.

**sangerdan** · 02-22-2014, 01:35 PM

This is way outside my expertise. but I've seen a hole in the strut supposedly to let water into the barrel. When you are sitting still the barrel should fill except for trapped air; even if nothing was forced in by forward motion is there enough of a low pressure area at the prop end of the barrel to suck the water out? If so probably not enough to suck a vacuum so it would have to pull water in from somewhere. How much water is needed to do the job? I'll bet all the motions going on in that area are violent enough to make sure fire knowledge if water is flowing through the strut bushing the way we'd like to think impossible.

**gn7** · 02-22-2014, 01:47 PM

Originally Posted by sangerdan

This is way outside my expertise. but I've seen a hole in the strut supposedly to let water into the barrel. When you are sitting still the barrel should fill except for trapped air; even if nothing was forced in by forward motion is there enough of a low pressure area at the prop end of the barrel to suck the water out? If so probably not enough to suck a vacuum so it would have to pull water in from somewhere. How much water is needed to do the job? I'll bet all the motions going on in that area are violent enough to make sure fire knowledge if water is flowing through the strut bushing the way we'd like to think impossible.

I personally believe, after putting the collar on it have little effect on bushing life, that it is NOT the pressure in front the feeds the bushing, but the negative behind the strut sucking water in. I don't see the benefit of the little hole in the set screw type collar Hotwater mentioned. I really don't see the need for a hole in the strut.
It takes very little water in the strut bushing to keep it happy. Some people swear it creates a hydraulic wedge like a main bearing. That's pure BS, because the length wise grooves in the strut won't allow a wedge to form.

I have had to run the boat in gear on the trailer before, and just let a garden hose stream on the shaft at the strut, and it was fine. Ran it for 10 15 minutes, no problem. Do it with out the hose, and you lose the bushing in a minute or less. If I had to bet on a magnaflow impellor or a strut bushing without water, I'd bet on the magnaflow out lasting the bushing.

**HotWater** · 02-22-2014, 02:17 PM

Originally Posted by sangerdan

This is way outside my expertise. but I've seen a hole in the strut supposedly to let water into the barrel. When you are sitting still the barrel should fill except for trapped air; even if nothing was forced in by forward motion is there enough of a low pressure area at the prop end of the barrel to suck the water out? If so probably not enough to suck a vacuum so it would have to pull water in from somewhere. How much water is needed to do the job? I'll bet all the motions going on in that area are violent enough to make sure fire knowledge if water is flowing through the strut bushing the way we'd like to think impossible.

I've seen a strut like that on a 68 Aquacraft. I thought it was a neat idea but I would assume the part would'nt be as strong.