Trojan Boat Forum

l am re powering the old girl
The new motors sit about 3" further back then the old motors placing the end of the shafts about 1" away from the front of the rudders
The mechanic says it is no problem. Comments please!

Will you be able to put the props on?

Big D wrote:Will you be able to put the props on?

And how far will the prop be from the strut . what size shaft ? I believe the rule is 1.5x shaft diameter max . I will check

Why are the engines being installed farther back ?

They can get the props on by turning the rudders sideways but I don't know about getting back off. The shafts are 1.25 "

prowlersfish wrote:....how far will the prop be from the strut...

Good point Paul. That shaft needs to be supported close to the prop.

If anyone can give me some type of document I can take to the mechanic it would be very helpful. see pic. http://i1123.photobucket.com/albums/l55 ... 003721.jpg

And does anyone if shafts can be cut down or shortened

Yes the shaft can be cut. Take them and the couplers to the machine shop. Hard to tell without the props whether they really need it or not though.

Big D wrote:Yes the shaft can be cut. Take them and the couplers to the machine shop. Hard to tell without the props whether they really need it or not though.

Agreed

Big D did you look at the photos of the shafts ??

I just look at photos and I can tell you the shafts are way to far from the struts . I will try and find some document ion but I do believe is around 1.5 X shaft diameter . and your way way past that .

A search on the net I came up the distance should be the same as shaft diamater in your case 1.25 one site even said 1/2 shaft diamater

I belive thats over kill .

" Distance between strut and prop hub should be no more than 50% of shaft diameter."

http://www.yachtsurvey.com/Alignment2.htm

Big d your take on the distance ??

My tri is stored for the winter. Measured and its = shaft size. Just over 1" from the strut and my shafts are 1-1/4.

I would have them shortened, putting the prop that far out on the shaft is going to be a TON of pressure on that without support and could lead to your shaft snapping and or wobble on the prop itself.

I don't have a side view but from this photo you can see small distance from strut bushing to prop hub. I would say the OP's photo shows the shaft much too far back.

ready123 wrote:I don't have a side view but from this photo you can see small distance from strut bushing to prop hub. I would say the OP's photo shows the shaft much too far back.

Agreed.

I don't have anything to do, so I'll go over and shoot some pics of the stock configuration from the side this afternoon.

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

OK. Here ya go. There are a few in this album to look at. Don't mind the nasty bottom paint, I don't.

Theres also an F-30 on the hard close to me, and some various shots of my favorite F-32 and the HBYC today. I also might have snuck in one of the last cruise this fall and one of Mr. Ewan on the dock.

https://picasaweb.google.com/1060575514 ... Season2012#

Dave Gerrs book is excellent to document strut to prop clearance. I agree the rule of thumb is 1/2-1 shaft diameter clearance.

It really bother me that someone in the marine field would say that sliding the shaft aft 3" is OK. It's not (fro a bunch of reasons) and I would be running from this guy if he was doing any work on my boat.

Cutting the shafts is no problem ... I had to when I repowered my F-32. Any shop that deals with prop shafts can do this... i wouldn't necessarily have just any machine shop do this, it should be a shop that's familair with shaft work.