grp sten tube Dia.

[bajo]

Please,Would it be a total mistake to use a 1 1/2'' OD &1 1/4''ID GRP tube with a 1'' prop shaft, this will be used with a bullflex coupling and a PSS seal, I'm trying my best to avoid having to go the stuffing box route ,the engine is a new 1GM10.The tube will be close 22'' long.

 

[charles_reed]

Not enough clearance there for your cutless bearing, unless you're going to have a P-bracket

 

[bajo]

Re: grp stern tube Dia.

Is this because the shaft will knock the outer grp tube sometimes times ? because I can get a cutlass bearing with a shell Diameter of 1 1/4'', not intending using a P bracket at the moment.

 

[TigaWave]

I beg to differ here, there is room for a cutless bearing.
25.48 ID x 31.60 OD
3 water ways 1.60mm depth
Min water flow 1 ltr /min

 

[Tranona]

Would suggest you consider using a Volvo shaft seal. Fool proof radial seal, no moving parts, cheap and very reliable - and no drips except when "burping " it to expel air when you launch.

Also because of its construction - it has a cutless type bearing inside it provides support for the shaft and you may find with that short shaft you do not need a cutless on the inboard end, although belt and baces, think I would install a half length (2") and then the shaft won't bang against the tube. This is the arrangement I have on my boat, also with a Bullflex and a 1GM. Been there for several years now and no signs of wear.

 

[TigaWave]

one question that will effect how the drive train perfroms.
How much shaft is there forwards of the stern tube/gland/seal?
Although this should be around 30.00mm how far from the rear to the prop? these distances will effect the bearing requirements.

 

[charles_reed]

To accept a 25mm shaft?

nm

 

[bajo]

Tranona,what is the OD of your stern tube ,and is it possble to sleve a 1 1/2'' tube (with epoxzing an internal reduction section of 1 3/4) to 1 3/4''an be able then to use a vp seal ,i have no idea about the inside of the vp seal
What is considered a medium or a long stern tube.I hate to bother the forum but every bit is a help.I have bought a bullflex ,and a max prop, plus alot of other intallation stuff,but its this decision on the stern tube that is presenting me with some problems,All please weigh in,Thanks

 

[Tranona]

The ID of the 1" Volvo seal is 1 3/4" so you will need to build up your glass tube to that OD. The overall length of the seal is just over 100mm of which 36mm is the part that clamps to the stern tube so you will need that length inside the boat, built up with glass tape and epoxy to 1 3/4". My installation was on an old Stuart Turner bronze stern tube with a bronze screw on housing that took the old stuffing box. I had it machined to 1 3/4" OD and internally to take a cutless. Strictly speaking short shafts like yours and mine - which is overall less than a metre should only require one bearing (maximum length between bearings is 1500mm), but I opted for one either end of the stern tube - the inner one is about 60mm long, because I originally had an R&D coupling which did transmit some movement to the shaft. The Bullflex is much better, but I left the inner bearing in. I also have a feathering prop (not a Max Prop as I am not rich) and the whole lot works very well.

 

[bajo]

ThanksTranona,I ordered a vp 1'' x1 3/4 seal today $96,I have not been able to get the size grp tubes here in usa will order from T Norris in uk I find this forum very helpful all info appreciated