Shaft Installation tips and tricks?‏

[DavidDW]

Happy New Year everyone,



I am interested in peoples opinions on the following.



I am about to put a pair of shafts into a boat that has never had shafts before – a quick background.



I bought an old 32 flybridge cruiser that was twin sterndrive powered with the aim of converting it to shaft drive configuration. 65 were built of the same model, 64 were shaft driven. All bearers and bulkheads were in the same positions as every shaft drive version I had ever seen. The boat came without engines and fuel tanks (basically just a bare boat that I got for the right price). I have stripped it out, set floor levels, rebuilt the transom the engine room and fuel areas. The rudders and rudder tubes are on the way and I have purchased props, engines and gearboxes. For those who saw my first long post on here, where I was leaning to 453 detroits and cringed at it, I ended up with a pair of 240hp range 4 perkins (straight 6) and new zf boxes (NEW very exciting!!!) :)



As you can imagine there is a lot to work out. I am about to embark on getting the running gear in so I can start finishing off areas and am after some guidance. I am based in Australia and have found getting information on the more complex aspects of boat building more than just a bit difficult.



I thought I would put the rudders in (a fibreglass post system from polyflex in Australia) http://www.polyflex.com.au/Products/rud ... rings.html similar to this but in glass (for some reason they don’t have it listed on their site…) Then work forward from there using



A 15% of prop diameter clearance between the front of the rudder and the back of the prop


15% of prop diameter clearance between the prop tip and the hull ( or 14.15” to the shaft centre given it’s a 21” prop). And


15% of prop diameter clearance between the front of the prop and the skeg (A frame)


I have a pair of ZF63As with an 8 degree down angle but the string line is telling me that the shaft angle will need to be ~12 degrees to get the clearance (annoying as I would like a flat engine installation).



I have the following questions.



I read the building tips on B31 very regularly and they are a great help. My situation if different from the re shafting article as I don’t have engines in the boat to enable me to do an alignment. How would you handle a situation such as mine? Is it just a matter of working out where the shaft should go through the boat, working out the clearances and then working forward from the rudder front edge to determine the A-frame position and necessary shaft angle, fabricating the A frame, then installing the shaft stern tubes with the dummy shaft to get an alignment? Wow big lot of questions there!

I haven’t bought the shaft stern tubes yet but am going to do it in glass (I Iike glass!) What do I actually need in terms of bearings, seals, tube etc to make up a kit to make it all work? (treat me like a first grade school student here as I have no idea! At this stage all I know is I need the tubes, and I hear about these things called bearings and seals but I don’t know how many of them I need, where they go or what size I need to get…. I am going to install 1 ¾” shafts.

My boat is balsa cored, in terms of glassing the tubes themselves, should I just follow the same lay up schedule as is in the shaft installation article in boat building tips? I thought maybe I should take out some of the core and fill the area between the inner and outer skin with epoxy thickened with cabosil.

I noticed the fibreglass wedges used to position the shaft tubes in place. Once the tubes are positioned, should I glue them in with epoxy thickened with cabosil before I actually glass the tubes into place? I am just a bit concerned about have a void on the underside of the tubes when I do the top layup from inside the boat and was thinking gluing them into place might remedy this?

Out of interest what is the typical shaft angle being run on a B31 diesel?

Please feel free to add in anything you think I might have missed in asking these questions. It is difficult trying to get it all in place in my mind.
Thanks for all the help this is a great site, so many of my questions are answered in the forums meaning I don’t have to ask as many questions!

[Tony Meola]

David

If you do a search under Bob Lilco's name, you should find a description of the set up he uses to lign up the shaft using a laser pointer. He makes an insert for the strut and has the pointer set in the insert. Maybe Bob will jump in and point you to the post.

[bob lico]

install rudders completely .now there are many varibles depending on what you did so far.i assumed you have installed the structs already and now you want information on the shaft logs is that what you are asking?with no shaft in place you go to a auto store and buy engine freeze out plug in the same size as shaft . drill 1/8" hole dead center and place in rear of struct to take place of shaft . purchase a cheap lazer flashlight like a teacher would use to point to a chalkboard . fasten to rudder and move till lazer goes thru hole in freeze out plug this is dead center of shaft if engine is in put "target" on gear output shaft of zf trans. lazer should be dead center of output shaft. now make new shaft log on ceters beween struct and gear output. this is a stock configuration if you were making shaft log for speed buy reducing shaft angle then shaft log struct and gears must be one unit . very difficult to explain in post.