Prop Shaft Diameter?

[Tim Good]

Ok so a very specific question here but you never know I might be lucky?

Does anyone know the diameter of a prop shaft coming from Yanmar 1GM10 originally fitted to a Beneteau Frist 26 from 1986?

10 points to anyone that knows. I need to buy mine before i go to the boat next and I forgot to take reference last time i fitted one.

Merci!

 

[Tranona]

Almost certainly 25 mm - but could be 22! The norm for a 1GM is 25 (or 1" but mainly UK and US boats), but some builders skimped and fitted smaller shafts. Might be worth giving Sillette a call as they have lots of data on prop and shaft sizes.

 

[Tim Good]

Almost certainly 25 mm - but could be 22! The norm for a 1GM is 25 (or 1" but mainly UK and US boats), but some builders skimped and fitted smaller shafts. Might be worth giving Sillette a call as they have lots of data on prop and shaft sizes.

But 22mm would still fit even if it were 25mm if i just tighten the bolts up right?

 

[alahol2]

But 22mm would still fit even if it were 25mm if i just tighten the bolts up right?

Highly unlikely and the prop would not sit properly either if it's the wrong size.

 

[Tranona]

But 22mm would still fit even if it were 25mm if i just tighten the bolts up right?

Absolutely not. The steel liner is a very close fit to get electrical continuity. You cannot even fit a 25mm on a 1" (25.4mm) so essential you have the correct size, preferably checked with a micrometer.

The correct method to fit them is as described by Vyv earlier. Locate the two halves on the (clean) shaft and support one while hitting the other. Then do the bolts up. Make sure the anode is clear of the stern bearing so that water can flow out of the bearing. If it is a P bracket the anode should be no closer than 15mm in front.

 

[alahol2]

I thought he wanted to buy a propshaft?

 

[Spyro]

You'll never know for sure without measuring. Presuming it is an anode and not a shaft you need to buy could you buy a 22 and a 25 and take back the one you don't need. My 2gm20 has a 22mm shaft. Difficult to get a 22mm anode but a 7/8 inch one fits ok.