Prop Shaft

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.

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Originally Posted by HotWater

I've seen some little sleeves that had a taper to the front that had holes drilled so water could supposedly pass through to the bushing. They only used two little set screws to hold them in place though. Can you get your shaft out without removing the rudder?

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Yeah,I think Bergeron may have made those up. I got one that was on a used shaft I bought for the material. It would work better than nothing. But back to back speed runs didn't show ours made any difference and the bushings last so we I leave it. As touchy as the boat is to props and its location on the shaft, I would have thought it might jack with the handling of the boat as well. But Bill says it doesn't. Move the prop back a 1/8th, and sounds off like a little girl.

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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.

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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.

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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.

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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.

Djunkie brings up a question of extra drag from a collar. I have often wondered if there is aeriation from the strut or if a collar is used would it be worse? GN7 stated no difference in speed testing so maybe it does'nt matter.

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Originally Posted by HotWater

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.

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OH THAT HOLE. That hole has nothing to do with the strut bushing. Its actually a pickup for the engine water. Cool idea, saved drilling another hole in the boat before they started putting the pickup in the cav plate. It worked reasonably well for the power the made in the day. Nicson made a slightly different version than the one pictured, where the inlet was on the side of the barrel right where the blade met the barrel. It didn't feed water to the bushing either, but from the outside it may have looked like it did.
There was a cracker running that had the water pickup for the engine in the rudder blade. Series of holes drilled in the side of the blade on a forward facing angle, that connected to a hole drilled vertically down the rudder shaft. Cool setup, but I think they ditched it

Attachment 34394
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Dan Bell, the owner of the GN boat "Priceless", makes the tapered shaft safety collars with water passages in them. They are made in both left and right hand prop directions.

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Originally Posted by steveo143

Dan Bell, the owner of the GN boat "Priceless", makes the tapered shaft safety collars with water passages in them. They are made in both left and right hand prop directions.

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Now that think about it, that is who made the one I have. Never use it. I do have kind of a issue with putting dimples or flats in the middle of the shaft, so its never been on the boat.

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Originally Posted by gn7

OH THAT HOLE. That hole has nothing to do with the strut bushing. Its actually a pickup for the engine water. Cool idea, saved drilling another hole in the boat before they started putting the pickup in the cav plate. It worked reasonably well for the power the made in the day. Nicson made a slightly different version than the one pictured, where the inlet was on the side of the barrel right where the blade met the barrel. It didn't feed water to the bushing either, but from the outside it may have looked like it did.
There was a cracker running that had the water pickup for the engine in the rudder blade. Series of holes drilled in the side of the blade on a forward facing angle, that connected to a hole drilled vertically down the rudder shaft. Cool setup, but I think they ditched it

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Attachment 34395Attachment 34396

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Yep you right! Guess I really did'nt pay attention to it. This must have been a race boat since it's got a drop through strut.Attachment 34407Attachment 34408Attachment 34409

Now that's a unique piece. I can't say I have ever seen one like that.

Have any of you guy's cut a slot in a shaft using a lathe?

I watched a video of an old guy who made a v-clamp that bolted to his tool post and that is what he used for cutting keyways. Seems like it would work pretty good, especially if you only have a lathe.

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Originally Posted by WESTERNAERO

He put a part in a "V" attached to the tool post, put a cutting tool in the spindle and ran the cross slide with the part across the spinning tool? Definitely creative but it's nice to have the free end of the part on a center.
It's not WW2, there's no need to be that clever. Take the shaft to a shop with modern equip and pay to get it done. <<<<<< Not trying to be a dick with this. I'm just saying, is the 50-100 dollars it's going to cost, worth all the effort of making something like that? I've run conventional lathes, mills, screw machines, grinders, threadrollers, etc. Now days I wouldn't even think about it with the technology that's out there in the machine tool world. Unless, you have a lathe and you like to tinker.

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No worries, I don't think you're a Dick. I like learning some of the info you provide. I'm just a Hillbilly that likes to tinker with stuff on nights and weekends and the shop's are'nt open then, so it's not about money more like convenience to do stuff when I can. As far as the effort of making something like that, I'm sure I could copy it in about an hour.

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Originally Posted by WESTERNAERO

He put a part in a "V" attached to the tool post, put a cutting tool in the spindle and ran the cross slide with the part across the spinning tool? Definitely creative but it's nice to have the free end of the part on a center.
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Funny, that was my first thought. Then I started thinking maybe he somehow locked the spindle and the end on a center, and used a cutting tool to broach a slot by dragging it over the shaft multiple times.
That's what I get for thinking too much:happy:

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Originally Posted by WESTERNAERO

Like an old profiling machine? Those things were brutal.

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They had a profiler of sorts, they called a broach, at McCulloch that rough cut the crank forgings. It look like a chain saw and threw chips like one.

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Originally Posted by gn7

Now that think about it, that is who made the one I have. Never use it. I do have kind of a issue with putting dimples or flats in the middle of the shaft, so its never been on the boat.

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do either of you have a picture of this ? or a contact of where to get one ? sounds like what i need

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Originally Posted by steveo143

Dan Bell, the owner of the GN boat "Priceless", makes the tapered shaft safety collars with water passages in them. They are made in both left and right hand prop directions.

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do you have a picture of this ? or a contact of where to get one ? sounds like what i need

Danny Bell (562-577-3673) has long narrow tapered collars that are drilled with a series of tiny holes in a way that deliver water to the strut bushing so they mount close up to the strut barrell. It's really an ingenious design, and are not as blunt as the one pictured in the RexMar pic (sorry!!) and not likely to divert water from the prop. Heath Hiebert uses one on GN369 and it works great. I think Jim Wilkes sells them too.

I was going to run this safety collar in front of the strut what do you guys think?

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Originally Posted by WESTERNAERO

What's wrong with running a 2 piece in front of the log? I don't understand the want to dig set screws into the side of the shaft.

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Nothing wrong with running a 2 piece in front of the log this would be in addition to the 2 piece in front of the log. I guess you could run a 2 piece in front of the strut too if you don't like set screws. What is the problem with set screws?