gear ratio?

[jim99]

Decided to install a new Yanmar 2YM15 in my little boat.

It was a simple question. What gearbox ratio do you require? 2.21, 2.62 or 3.32.

The more I look into it, the more confused I become. My auxilary's main job has always been getting in and out of tight places and charging batteries.

Does ratio really matter?

 

[oldsaltoz]

Yanmar should be telling you, but only after you tell them about what it's going into, Boat manufacturer, mode, length, existing shaft and prop size etc.

Avagoodweekend......

 

[jim99]

Thanks for that. Yanmar dealer asked me. They know the boat, but perhaps not the precise details. Felt a little stupid not being able to promptly answer.

 

[Pye_End]

What size prop do you intend to swing?

If you have a max diameter you are working to, then you can work back from there.

 

[PCUK]

Large slow revving props are the most efficient - but cause the most drag when sailing. A large folding prop' on a 3:1 ratio would be the best option if it will fit!

 

[jim99]

Comments noted and appreciated. Thanks.

I emailed the dealer back and then he essentially asked all the questions oldsaltoz asked and a few more.

I'm in Bangkok and boat's in Langkawi, so measuring will have to wait a bit.