Split Shaft and one piece shafts

[1Hogtow]

Hi guys,
Back again for my next round of wisdom.
I have a 1979 60 convertable with 2 1/2 inch shafts. Both of the shafts are one piece but the spare is two piece. Any ideas why? Is this typical or something the previous owner did?

Also,
any ideas on fuel burn?
We have 12V71 TI's that I think are 650hp.

Boat is curently out of the water getting the following done;
New PSS's
New Cutlass Bearings
New bottom paint
New stripes
New zincs
New transducer
Converting the holding tank back from fuel to black water.(stupid)

Thanks in advance for any help.

[Airpilot]

I have a 1978 60ft. sportfish and it has split shafts. If you damage a shaft with my setup you can undo the short shaft from the coupler and replace it...other than that I would think that a single shaft application might be more efficient. I have 650 hp 12-71s and burn 68 gph at 2150 rpm. hope this helps

[MikeP]

Carrying a non-split shaft on board is a bit difficult...

Many (all?) of the Hatts in the 53/58 versions came oem with split shafts on both sides. Don't know about other Hatts.

[1Hogtow]

Airpilot,
Thanks for the info. Any idea on the fuel burn around 1500 or 1700?

I understand having a spare one piece shaft would be difficult but, the real question is why do I have one piece shafts installed. I think someone changed them but, who knows.

The yard just called me and the port strut is misaligned with the stuffing box by about 1 1/2 inches. They say the right thing to do is rebed the strut. Another 10hrs labor.
Brad

[SKYCHENEY]

Airpilot probably can't give you fuel burn numbers at less than planing speeds. I have yet to see him run at hull speed for less then about 2 miles. He's got a lead foot (hand).

[DCMY #92]

If I had to guess, I would say that your installed shafts are replacements and your spare is an original. Hopefully, both shafts were replaced after only one was damage. You might consider having your spare shaft sections checked for runout (make sure they are straight). If both original shafts were damaged in a previous event, your spare could be the least damaged of the two.

Sorry to be so pessimistic, but Murphy is alive and well.

I have a spare single piece bronze shaft for our 41. When I bought her 26 years ago it came as a spare. Both installed shafts are stainless steel. I have kept the spare all these years, but I'm not sure why. I'll never install the bronze shaft to replace a SS shaft permanently, and it won't fit aboard to carry as a spare. I have considered cutting it in two and buying a coupling, but the coupling costs almost as much as a new SS shaft.

With scrap prices so high, I should sell the bronze spare, but I can't seem to bring myself to do so.

[Airpilot]

That really hurts Sky... ok your correct of course but I am not the guy going WOT in an 8kt speed limited area.....your so bad!

[DCMY #92]

Brad,

If the strut isn't aligned properly, you have to fix it. Vibration and shaft breakage are in your future if you don't. Before you simply commission rebeding, you might ask the yard, or a surveyor, to look for the root cause of the misalignment. 1 1/2 inches is a huge displacement. A blind yard monkey should be able to install a strut closer than that.

[luckydave215]

Brad, my '79 has 2-1/2" one piece shafts.
I have no idea if they're original......and I don't have a spare of any kind.

[Trojan]

Brad,

If the strut isn't aligned properly, you have to fix it. Vibration and shaft breakage are in your future if you don't. Before you simply commission rebeding, you might ask the yard, or a surveyor, to look for the root cause of the misalignment. 1 1/2 inches is a huge displacement. A blind yard monkey should be able to install a strut closer than that.

You bet. If your strut is that far out something is really wrong. Find out what caused it to be that far out. Something doesn't sound right. Re-beding may not correct the problem. A lot depends on the strut length.
Check it out.
It's easier to keep full length shafts in line. If the coupling is not correctly installed they can give you all kinds of problems

BILL