Lavezzi 40: Does Lavezzi originally have 1 left and one right turning Propeller or both right

[CaptainRivet]

Hi all,
Does Lavezzi have 1 right and 1 left turning Propellers or both right.
Due to FFOF I have 2 right, due to my boat neighbor who is an retired boat engine mechanic the cat must have 1 right and 1 left. I am in a Harbour where the water is extremely dirty and smelly, so going in and checking is no option.
Due to the mech you cannot see it in the installation as the 130S Volvo saildrive does both directly.
Thank you.

[singlespeed]

Move boat into a relatively open area on a wind less day... Put both engines into reverse at just above idle, center the rudders and apply the wheel brake. If it backs straight, likely your props are turning in opposite direction. If it slowly turns in one direction, you have one clockwise and one counterclockwise prop.

[lyleh]

I just looked at the survey photos for my 2009 Lavezzi 40 with Volvo D1-30’s and both propellers turn counter clockwise.

[CaptainRivet]

Originally Posted by lyleh

I just looked at the survey photos for my 2009 Lavezzi 40 with Volvo D1-30’s and both propellers turn counter clockwise.

Thank you, yes thats what Flex-o-fold told me too and what i ordered and mounted.
And assume when Volvo factory mechanic swapped and upgraded engines they done the same with the new D2-50 and 130S saildrive

[CaptainRivet]

Originally Posted by singlespeed

Move boat into a relatively open area on a wind less day... Put both engines into reverse at just above idle, center the rudders and apply the wheel brake. If it backs straight, likely your props are turning in opposite direction. If it slowly turns in one direction, you have one clockwise and one counterclockwise prop.

I think you mean if it turns when reversing both propeller turn in one direction.

[SailingHarmonie]

Originally Posted by CaptainRivet

Thank you, yes thats what Flex-o-fold told me too and what i ordered and mounted.
And assume when Volvo factory mechanic swapped and upgraded engines they done the same with the new D2-50 and 130S saildrive

If you mounted two left hand props on the boat, and the boat does not spin in a circle with both engines in forward, that should have answered your question with way more authority than anybody here.

[HeywoodJ]

Sailing catamarans are frequently (generally?) delivered with same rotation engines/propellers. The distance between them is much greater than most twin-screw motorboats, and so many of the effects experienced without counter-rotation that the OP's retired boat mechanic mentions are much less significant. Ideally, yes, you could have counter-rotating props, but the benefits are not huge.

With same rotation you will find that she walks a bit better one direction than the other.

The big reason on twin-screw motorboats is to not have to constantly apply helm to go straight, at least on our same rotation 50' cat the rudder angle indicator is zero when ahead on both engines and we still go straight - the hulls are designed to track more than motorboat hulls.

The distance between props is also why you will rarely see the expense of synced engines on a cat, the retired mechanic would likely expect that as well, and it quite an issue when the wash from one prop interacts with the other, but again, not so much with the large distance between the props and the relatively large rudders of a sailing cat.

Yes, it is a money-saving thing for the builders, but having driven both I suspect there is a reason the market has not spoken loudly that cats need to be delivered with counter-rotating props.

[CaptainRivet]

Originally Posted by SailingHarmonie

If you mounted two left hand props on the boat, and the boat does not spin in a circle with both engines in forward, that should have answered your question with way more authority than anybody here.

Point is they are mounted but i didn't have a chance to do a big test ride. just realized they are quite different in berthing compared to fixed prop. After a 9month repair on drydock because of an 8m pyramide wave slamm damage where we also fixed all production issues and improved structure by 400% i am at the pontoon since 2,5month and done a huge Lithium install and wired all 230V and most 12, soon 24V new plus installed a fully electric galley. This because cat was empty and nearly all panels away, took a bit longer then planed. But my window closes where i could hand one prop pack to FFOF and swap to one roatating in opposite direction.

[CaptainRivet]

Originally Posted by HeywoodJ

Sailing catamarans are frequently (generally?) delivered with same rotation engines/propellers. The distance between them is much greater than most twin-screw motorboats, and so many of the effects experienced without counter-rotation that the OP's retired boat mechanic mentions are much less significant. Ideally, yes, you could have counter-rotating props, but the benefits are not huge.

With same rotation you will find that she walks a bit better one direction than the other.

The big reason on twin-screw motorboats is to not have to constantly apply helm to go straight, at least on our same rotation 50' cat the rudder angle indicator is zero when ahead on both engines and we still go straight - the hulls are designed to track more than motorboat hulls.

The distance between props is also why you will rarely see the expense of synced engines on a cat, the retired mechanic would likely expect that as well, and it quite an issue when the wash from one prop interacts with the other, but again, not so much with the large distance between the props and the relatively large rudders of a sailing cat.

Yes, it is a money-saving thing for the builders, but having driven both I suspect there is a reason the market has not spoken loudly that cats need to be delivered with counter-rotating props.

Thanks, that what my surveyor told me too, so most likely they install the new with 2 in same direction