shaft length????

[lobsta1]

After launch today, waited for bridge to open. Shifted to fwd & lost propulsion on stb motor. Think shaft snapped as it is still turning inside. So, does anyone have an idea of the shaft length on a gas B33?

[mouldrp]

I lost a shaft on my FBC several years ago. I could try and find the order invoice for my shaft’s length, but I recommend that you hall the boat and get an exact measurement.

Like every thing for a boat the shafts are not cheap so, like the adage goes, you “measure twice and cut once”.

Hopefully, the shaft didn’t break aft of the strut or you’ll be looking for a new prop as well.

I was lucky, as mine broke backing into my slip and my wife heard it and made note of the boat’s location. I had a diver go down on the spot my wife suggested and he found it on the first try with only about half of one blade sticking out of the mud.

Good luck, depending on availability and delivery it should be a quick fix.

[h2ojst]

My shaft length size won't help you because my 8 degree downangle transmission is shorter than your 72 series BW. I'd take an accurate measurement of the other shaft once you're out of the water which I assume you will have to do to replace the shaft anyway, right? It can be done in the water, but it's not easy and I honestly don't remember if the rudder's had to come off also or not.

[lobsta1]

I know I need an exact measurement, but I was trying to get an idea of the length so when I talk to the shop I can get a rough cost estimate.
Al

[Camano Mike]

I have the original drawing for fabrication for the shafts in my 87. I'm going by the yard today to check on progress. I'll see if I can dig that out.

[h2ojst]

Al, my shaft length is 85 1/4 & like I said, that's with the downangle gear box, so your shaft should be about 2" or so longer. When you go measure, the distance between the prop and the strut should be no more than 1/2 the shaft diameter. Also, have the machine shop fit the prop to the shaft, so the taper is perfect. Mine broke because the keyway was broached incorrectly. Good luck.

[h2ojst]

Afetr thinking about this, the downangle box is shorter, but I also moved my engines back, so the shaft size may be the same? Anyway, this will get you close.

[lobsta1]

Thanks Joe,
Gave the prop shop a rough measurement of 8' & they came back with a quote of $1460. Another $1850 for a 21 x 18 3 blade Dynajet. That's if they can source one locally. If they have to order from Michigan, 3 months to whatever. Might as well replace cutlass bearings at this time. He also recommended that I pull the other shaft & have it checked out. With the boatyard haul out fees & storage, I'm probably looking at $5000.
At least I won't be buying gas for a while.
Al

[h2ojst]

There goes your Summer, Al. I would definitely pull the other shaft. That's why I now have a spare......and another pair of wheels. Isn't boating fun?

[Camano Mike]

I found the drawings. For 1987 with either 340 mercruiser or 350 crusader and 1-3/8" shaft, the length is 85-1/4". The same motors with 1-1/2" shaft, the length is 85-3/4". Taper at the propeller is listed as .750 per foot, 3-7/8" for 1-3/8" shaft and 4-1/4" for 1-1/2" shaft.

[Camano Mike]

https://ibb.co/99CbjXd
https://ibb.co/1RgPbd7
https://ibb.co/kGg9nfr

Here are the pictures from the drawings

[lobsta1]

Thanks guys. I might end up ordering a new shaft online. As far as a prop, I found a reconditioned dynajet 21 x 18 up in Maine. Only thing is it is bored 1 3/4". I don't know if using a bore reducer to bring it down to 1 3/8' is a good idea.
Al