Shaft logs

[CEShawn]

I was just curious as to how hard it was to install a shaft log. Figure if you had the alignment done already. Anyone have experience with this as i know this must require it. How is shaft angle determined, is it worked back from the prop going to route that you want the biggest prop at the lowest angle then figure which gear applies and then that dictates where the engine sits. I know they always want the engine as far back possible but what truly dictates that.

Just sitting here dreaming how de boats are made...

 

[eyschulman]

No simple answer. That is what marine architects and enginers do. Lots of options V-drive,remote v-drives-tilted motors -down angle transmissions-tunnels Etc.

 

[CEShawn]

<----- marine engineer unable to sleep dreaming about running gear!

 

[captainlarry84]

I think the key is to first determine where the engine e must go. Next is the gear you can get down angle gears to assist you in getting the proper shaft angle & aliment. Next the hole is bored in the keel with the approximate angle needed. The coupler and gear are then connected. The shaft log at the rear is still floating and can be moved a little, Once shimmed into place it is then glassed in if a wet tube is used or bolted in if a bronzed shaft log is to be used. You are always better off with the wet tube. The bronze boxes in may cases require a wet keel. Carry all of that water plus the shaft turning in all of that water is drag and not the best way to go.

 

[dsharp]

The bottom of the bell housing and oil pan in relation to the crankshaft center line will pretty much dictate engine placement. My Dad would lay out the shaft line, strut, etc on two sheets of plywood with the boats bottom profile drawn on it.

 

[F/V First Team]

that seems like a really hard way to do things... but if it works for you then i guess its ok

shaft tubes are easy. cut a hole, slide in mr tube. put your engine where you think you want it and start aligning. shims are your friend and with them you can control movement up and down as well as side to side (if you're moving fore and aft then you're doing it wrong - the engine shouldnt be traveling in this direction easily.

hardest part of this install is glassing the tube in place. sure you can reach both ends but what of the middle? the more surface area that you can attach to the better. i prefer to go through the top when joining the units together but one could go through the side as well - just cut a channel and glass it back in place when done.

and if you arent repowering, the job is made that much more simple since the major aligning is already done for you. the shaft coupling will bring things in align for the tube to be glassed.

easy stuff that requires time and patience because it is trying to trick you into thinking that it is extremely difficult. the worst part will be going up and down through hatches.

pft, bronze stuffing boxes