Volvo Penta SailDrive comparability.

[Bob Locke]

I have a vintage Baltic 37 with the Volvo Penta MD11c engine. The sail drive is 40 years old and needs to be replaced. My question is what SailDrive units work with this engine. I think I have either the 100 s or the 110 s. It’s a freshwater boat and the engine is fine. There are some newer SailDrive ie. 120 and130 s. and would they work with the engine. I need to purchase a used or rebuilt sail drive and the yacht yard mechanic will change it out. I have seen several on eBay but don’t want to purchase
The wrong my one.

 

[Slowtack]

The newer saildrive and engines have different spline system to the older models... On the drive shaft but I think there are adaptors available.... The gaiter ring bolt pattern was unchanged when I upgraded in 2017.

 

[Bob Locke]

The newer saildrive and engines have different spline system to the older models... On the drive shaft but I think there are adaptors available.... The gaiter ring bolt pattern was unchanged when I upgraded in 2017.

 

[Bob Locke]

I think that the SailDrives that I am seeing on eBay are older and the yard is going to message me the correct SailDrive number for the one I am replacing tomorrow. I will talk with the mechanic about what is available. They look very similar to mine on line.
Thanks
Bob

 

[Tranona]

Apart from the spline issue the other major problem will be the reduction ratio. I think you will find yours has a 1.6:1 to match the slow revving engine whereas most of the 120s had 2.15:1 as they are fitted to 3600rpm engines. A 1.6:1 is listed but doubt you will find one. You will need a new propeller.

 

[Bob Locke]

Apart from the spline issue the other major problem will be the reduction ratio. I think you will find yours has a 1.6:1 to match the slow revving engine whereas most of the 120s had 2.15:1 as they are fitted to 3600rpm engines. A 1.6:1 is listed but doubt you will find one. You will need a new propeller.

Everything I have seen so far has 2.19:1 reduction. I wonder how to solve that problem. I think the MD 11 c engine is a 23 horse unit. I do have a feathering prop that works. Any thoughts on the reduction problem? Thanks for your feedback

Bob

 

[Bob Locke]

Everything I have seen so far has 2.19:1 reduction. I wonder how to solve that problem. I think the MD 11 c engine is a 23 horse unit. I do have a feathering prop that works. Any thoughts on the reduction problem? Thanks for your feedback

Bob

Could the reduction ratio problem be solved by replacing the current propeller. Seems all of the reduction available are 2.19:1 perhaps that is what you meant when you said I will need a new propeller.

Bob

 

[Tranona]

Using a 2.19 will reduce your shaft speed by approx 400 rpm which will mean that you will be "overpropped". Depending on your type of feathering prop it can either be repitched or new blades for a larger diameter and or different pitch. How problem with the prop hub as they are the same. Suggest you talk to the maker of the prop

 

[Bob Locke]

Using a 2.19 will reduce your shaft speed by approx 400 rpm which will mean that you will be "overpropped". Depending on your type of feathering prop it can either be repitched or new blades for a larger diameter and or different pitch. How problem with the prop hub as they are the same. Suggest you talk to the maker of the prop

Sounds as if the 2.19 reduction ratio on the Sail Drive would work but if I were to have the Sail Drive installed I would need a new prop for the replacement . Am I understanding you correctly. If I buy the replacement Sail Drive I will need the appropriate propeller.
Bob

 

[Tranona]

Yes you will need a different size prop, but not necessarily the one that comes with the drive (if there is one) as the drive was used on a huge range of engines using props varying in diameter from14-19". While the choice of size is fairly limited for any given engine size - for example the 30hp normally has a 16" 2 blade but a choice of 3 different pitches depending on the boat's weight, where you have a non standard combination of engine and drive like yours you need to go back to basics and calculate the size from the boat data, engine and reduction ratio. If you have a 3 blade feathering then a Maxptop is infinitely pitch adjustable, if a Featherstream they will calculate an optimum size and provide you with a set of stops for your existing prop. Other props are different and may need new blades.

 

[Bob Locke]

Yes you will need a different size prop, but not necessarily the one that comes with the drive (if there is one) as the drive was used on a huge range of engines using props varying in diameter from14-19". While the choice of size is fairly limited for any given engine size - for example the 30hp normally has a 16" 2 blade but a choice of 3 different pitches depending on the boat's weight, where you have a non standard combination of engine and drive like yours you need to go back to basics and calculate the size from the boat data, engine and reduction ratio. If you have a 3 blade feathering then a Maxptop is infinitely pitch adjustable, if a Featherstream they will calculate an optimum size and provide you with a set of stops for your existing prop. Other props are different and may need new blades.

 

[Bob Locke]

Yes you will need a different size prop, but not necessarily the one that comes with the drive (if there is one) as the drive was used on a huge range of engines using props varying in diameter from14-19". While the choice of size is fairly limited for any given engine size - for example the 30hp normally has a 16" 2 blade but a choice of 3 different pitches depending on the boat's weight, where you have a non standard combination of engine and drive like yours you need to go back to basics and calculate the size from the boat data, engine and reduction ratio. If you have a 3 blade feathering then a Maxptop is infinitely pitch adjustable, if a Featherstream they will calculate an optimum size and provide you with a set of stops for your existing prop. Other props are different and may need new blades.

I replaced the 110 SD with a120 SD.
2.19 1 and it works but can only get 1200 rpm either the replacement drive. The engine is only 23 HP. I don’t think my prop is a feathering prop but rather, an expensive folding prop.

Bob Locke