Prop Distance

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   Ok after a bend propshaft due to alignment i think, im wondering how far the prop should

A, be away from the strut

B, be away from the rudder

C, be away from the floor

i ask this because the prop was quite close to the rudder and a long way from the strut and floor but looking at my friends 2001, the prop is close to the strut and floor.

im thinking theres a formula to work out the optimum positioning. but i don't know it.

oh and my lovely craft is a 79' ski nautique

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Bman Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: March-13-2006 Location: United Kingdom Status: Offline Points: 19	Post Options Post Reply Quote Bman Report Post Thanks(0) Quote Reply Topic: Prop Distance Posted: July-18-2006 at 5:57pm
	Ok after a bend propshaft due to alignment i think, im wondering how far the prop should A, be away from the strut B, be away from the rudder C, be away from the floor i ask this because the prop was quite close to the rudder and a long way from the strut and floor but looking at my friends 2001, the prop is close to the strut and floor. im thinking theres a formula to work out the optimum positioning. but i don't know it. oh and my lovely craft is a 79' ski nautique

Tim D Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: August-23-2004 Location: United States Status: Offline Points: 2641	Post Options Post Reply Quote Tim D Report Post Thanks(0) Quote Reply Posted: July-18-2006 at 9:44pm
	The drive shaft is tappered and so is the inside of the prop, both mate together to a certain point.
	Tim D

Bman Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: March-13-2006 Location: United Kingdom Status: Offline Points: 19	Post Options Post Reply Quote Bman Report Post Thanks(0) Quote Reply Posted: July-19-2006 at 1:16am
	Yes i know that let me ask the question another way, How long should the prop shaft be on a 79' ski nautique?

79nautique Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872	Post Options Post Reply Quote 79nautique Report Post Thanks(0) Quote Reply Posted: July-19-2006 at 9:34am
	it should be 50" long 1" diameter shaft from the factory. make sure it has not pulled out of the coupler. Check where it mounts to the tranny and make sure the the end of the shaft is pretty close to flush with the face of the coupler, you'll have to remove the four bolts and slide it back to see.

David F Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: June-11-2004 Location: United States Status: Offline Points: 1770	Post Options Post Reply Quote David F Report Post Thanks(0) Quote Reply Posted: July-19-2006 at 10:38am
	79Nautique: How far away is the prop hub from the strut with a 50" factory length shaft? I think this is what Bman is asking. And, can that distance be shortened a bit without putting the prop blades too close to the bottom of the hull for comfort. Seems to me that the close the prop hub is the strut the better (to help reduce vibration and fatigue). I seem to remember others having issues with broken shafts due to the distance between prop and strut...or at least that was the suspected cause.

79nautique Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872	Post Options Post Reply Quote 79nautique Report Post Thanks(0) Quote Reply Posted: July-19-2006 at 10:42am
	you can shorten it I use a acme 470 with a 49 1/2" long shaft on mine. Talking with Dennis at MWCC he gave me the 50" and it's about an 1" or so from the strut

David F Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: June-11-2004 Location: United States Status: Offline Points: 1770	Post Options Post Reply Quote David F Report Post Thanks(0) Quote Reply Posted: July-19-2006 at 11:11am
	I think an 1" from the strut should be fine and maybe give a little more freedom in choosing props. But closer is better for fatique/vibration resistance IMHO. What prop are you running and what is your prop to hull clearance?

Bman Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: March-13-2006 Location: United Kingdom Status: Offline Points: 19	Post Options Post Reply Quote Bman Report Post Thanks(0) Quote Reply Posted: July-19-2006 at 3:29pm
	thats more like the info i need cheers, i am a tad confused still as the that bent was 48" long but i had 3-4 inches between the strut and prop but 1/2 - 3/4 of that could of been distance from the gearbox to shaft as there was a gap. im beginning to wonder how original the strut is, it was well out of alignment when i took it of ( it was in line with the engine but it rubbed out the top front and bottom rear of the bearing) and it also had 1 good 1/4'' packing in the front bolt holes to reduce that also. Has anyone got a pic and maybe the angle the strut should be? Cheers Guys

Bman Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: March-13-2006 Location: United Kingdom Status: Offline Points: 19	Post Options Post Reply Quote Bman Report Post Thanks(0) Quote Reply Posted: July-19-2006 at 3:33pm
	OOh not sure of the prop but although i didnt think it was that bad, a friend of a friend who's sorting it said it was well shafted excuse the pun. im thinking its original or at least original spec, was looking at those acme props from skidim there seroiusly cheap compared to a standard one over here. just the postage that may kill the bargain. Don't suppose anyone has a technical drawing of a suitable prop?

Prop Distance

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