Shaft Separation

[rondds]

i've heard several instances of shafts shearing off, either at the stuffing box, or at the cutlass bearing. it's understandable that this could happen with years of torsion, spinning, and wear from a bit of abrasive (sand,mud etc), but what is maintainence protocol to prevent/inspect/anticipate such a disaster? i know shaft logs need to be cool, a drip a second or whatever the rule of thumb is (old boats like mine dont have dripless), but how can you tell? after a long run, i've climbed down the bilge to check the temp of the shaft and shaft log and never felt any warmth.

 

[fwebster]

Wear, abrasion, heat, etc are not the issue, flex in the shaft is the problem. That leads to metal fatigue and an eventual break. When you hear about a shaft break, its always either right behind the coupler, right behind the strut or where the taper ends. As long as your shaft has a normal amount of run-out and you keep your engines aligned you don't have to worry.

 

[sbw1]

My brand new 37 express broke its port shaft in a big following sea when the boat was just a few months old. The dealer mentioned that there had been a few of them. The boat had never been run aground, hit anything and there was no vibration or warning other than some noise and a high reving engine that was immediately throttled down. I installed dripless shafts shortly after that and kept wooden plugs in the bilge in case of a thru hull failure which never happened. There was some talk of the shafts being a tad on the skinny side and I know I was not the only one to have this issue with a 1993 37 express. It could have been a vendor issue for all I know. Shafts are typically available in any state in the country because the type of steel is a commodity. Most people around here do not own a spare because they can be overnighted and you can usually have exactly what you need anywhere in Michigan in a day or two. The dripless shaft logs are worth doing just to avoid the hassles associated with maintaining the old system. It's nice having a dry bilge.

 

[rondds]

i replaced my wax shaft log packing with this stuff
http://www.e-marine-inc.com/products/gfopacking/packing.html
and got a dry bilge too. it's pretty amazing stuff and i recommend it to anyone, esp those of you with impossible to reach v-drives. a much simpler concept than dripless shaft logs (less to go awry) and MUCH less costly. i've had it for two seasons now (almost 80 hours) without incident. the lack of "drip" was alarming at first, which is why i kept checking the temperature after running the boat.

 

[boatdoc100]

I have installed 100's of P.S.S. driples shafts. They really are the way to go. Especially on the older 34, 37 and 39 Sea Rays that all had that diamond shaped packing with the cotter key at each end. They never stop dripping. A pair of 1 1/4" stern tube by 2 1/4" shaft (which is what a 34 takes) will run around 600.00. Remember though this is a one time cost and a dry bilge forever.
Brad
Pflieger Marine Services

 

[PlayDate]

I'm a big fan of P.S.S. dripless shafts as well. It is an upgrade that well worth the cost. In regards to shaft breakage, Frank called it. Most issues deal with alignment or hitting something. In the case of SWB1, rough seas can break driveline parts....although it is a bit unusual. In that case it may have been a flaw in the manufacturing process that caused the premature failure.

-John

 

[MarkD]

I think ,my buddy Rondds is worried about his since I had a problem with mine. Like Frank said, a had a break just aft of the strut on the stbd side running gear. Heard & felt a vibration for about 5 seconds before coming down to idle. Hit reverse and BANG, the prop and shaft went to Davie Jones locker. Prior, I had felt nothing unusual. Amazing to me that this happened. I do remember last year hitting something in the water at about 5mph (not hard, just a thud). Never though another minute about it and even checked the props in the fall. No damage. Wonder if I could have seen it coming and done something different...... I guess I could have aligned the engines each year but that is just a pipe dream IMO. I am now having this fixed over the winter and should be good as new in the spring.