Prop Shaft

[ksmith]

I had my new boat bottom cleaned yesterday. The diver says I need a zinc and to measure my prop shaft for the size. When I told him it was probably 3/4 everyone said no 1 1 1/4. When I check the owners manual for my 1977 Columbia 8.7 it says 3/4. Course I am going to dig out the calipers. How ever was wondering why 3/4. Is it a engine thing volvo penta 2002 is in her now. Pretty certain not the orginal engine. Course it is what it is. Just curious.

[scubasteve]

When repowering, most people will size the engine comparable to what they had before. Changing packing boxes, shafts, props ext can get expensive. That being said, it probably original running gear or at least size.

You're on the right track, measure with calipers. 3/4 is about the smallest shaft you would run but seems fine for a 27. 1 1/4 seems way overkill.

I've had good luck with boatzincs.com

[SkiprJohn]

My friend with the Columbia 28 has a 3/4 shaft. It originally had an Atomic 4. Its really hard to find things to fit his shaft because everything seems to fit larger 1" or 1 1/4".
Your avatar indicates a Tartan. Do you have more than one boat?
Kind regards,
JohnL

[ksmith]

John: Your right changed boats just did not change avatar. I have do so. Mine is a Columbia 8.7. But still curious about prop shaft size.

[captain465]

Seems like it would be easy enough to access the shaft from inside the boat (just after the coupling) and measure it there.

[fstbttms]

Originally Posted by ksmith

How ever was wondering why 3/4.

Why not 3/4"? Is is a standard shaft diameter, nothing unusual about it. It's lighter than a larger diameter shaft and plenty strong enough to do the job on your boat.

BTW, not only should your diver have been able to identify the shaft diameter (either by eye or with a caliper) but he should have had the zinc to install as well.

[endurance]

Slightly off the subject .. how many zinc anode do you have and planning on installing?

I had two on my H320, when I pulled it this year, both were gone. I asked my marina to put 3. I keep the boat in the water and pull every year for bottom paint.

Rick

[ksmith]

Thanks everyone. Got it figured out. It is a 1" shaft and it now has a fresh zinc. I have the bottom cleaned once a month. My diver is a fellow LA. First he cleaned the bottom and prop. Then said you need a zinc. Then showed up and put the zinc on and told me (what I had already determined by caliper) its a 1". That will be $30.00 please.

[fstbttms]

That was just for the zinc install, yes? Hard to imagine thirty bucks covering both the hull cleaning and zinc installation.