42DS reversing performance

[[3889]]

+1

A bow thruster is a get out of jail free card!

But not free, and begs the question whether you should be out of jail if you need one but can't be bothered
to skill up ?
As to the OP, I've had a similar experience with an Oceanis 40. Inexplicable as I've sailed dozens of AWBs with similar hull/prop/keel configurations which handle well astern, my own, bland SO36i is entirely predictable. Maybe some boats sacrifice astern handling completely by moving the rudder post to improve the G&T space?

 

[pagoda]

Not unlike the OP, we went from 35ft fin keel Jeanneau with a Kiwiprop to a 42i Performance, with a Flexofold prop on a shaft. On the old boat we had quite strong but predictable prop walk. The 42i has the same hull as the 42DS (but a deeper keel in the P version) We have found minimal prop walk . There is more lag than with the Kiwi prop, but the boat reverses OK. We have found the biggest change in windage and low speed steering. The bow thruster does help when you are turning in confined spaces. Not the whole solution but often helps. It takes a while to get the feel of a new boat under you

 

[duncan99210]

I have a Brunton on my boat and get next to no prop walk in astern. However, its fitted on a Saildrive so may be giving different characteristics than if it were fitted to a shaft drive.

 

[Rob_Webb]

Is it true that Jeanneau currently fit Flexofold 3B props to all their new boats?

 

[Tranona]

Is it true that Jeanneau currently fit Flexofold 3B props to all their new boats?

No. They are a factory fit option, although as they sell through dealers it is quite possible that buyers might choose a different prop. However the FlexoFold is highly regarded.

 

[Mistroma]

But not free, and begs the question whether you should be out of jail if you need one but can't be bothered
to skill up ��
As to the OP, I've had a similar experience with an Oceanis 40. Inexplicable as I've sailed dozens of AWBs with similar hull/prop/keel configurations which handle well astern, my own, bland SO36i is entirely predictable. Maybe some boats sacrifice astern handling completely by moving the rudder post to improve the G&T space?

I don't think that 42DS sacrifices astern handling in favour of increased volume. There will have been compromises but astern handling doesn't jump out. As I said previously, the OPs reversing problem isn't something you'd expect with a 42DS. The 42DS doesn't have a big problem with prop. walk under normal circumstances. It must be something specific about the particular boat he tested. It should be correctable.

 

[KellysEye]

>What help is that to the OP who is buying a fin keel Jeanneau?

I don't think keel type makes any difference blipping makes the boat go straight, prop walk is a prop problem.
.

 

[Tranona]

>What help is that to the OP who is buying a fin keel Jeanneau?

I don't think keel type makes any difference blipping makes the boat go straight, prop walk is a prop problem.
.

That is not what you said. You were very specific about it being what you did on a completely different kind of boat. If you think prop walk and the resulting influence on astern handling is a universal problem and your method is also universally successful then say so, otherwise your comment is worthless. However, not sure that you will get much agreement to your proposition!

 

[Rob_Webb]

Update. Couple of days ago I donned snorkel and observed what happens to my Volvo folding prop as my wife cycled between slow ahead-neutral-slow astern a few times. As expected the prop snapped fully open for ahead, then collapsed at rest under it's own weight for neutral, then partially opened (I'm guessing about 30%) in reverse.


So no wonder it feels like the prop has fallen off when going into reverse.


So still debating 3B Flexofold vs 3B Maxprop based on other user's experiences.

 

[RichardS]

Update. Couple of days ago I donned snorkel and observed what happens to my Volvo folding prop as my wife cycled between slow ahead-neutral-slow astern a few times. As expected the prop snapped fully open for ahead, then collapsed at rest under it's own weight for neutral, then partially opened (I'm guessing about 30%) in reverse.


So no wonder it feels like the prop has fallen off when going into reverse.


So still debating 3B Flexofold vs 3B Maxprop based on other user's experiences.

I assume that the test was with the boat tied alongside or at anchor? That might be an unfair test as once the boat actually starts moving backwards the motion might fully open the prop so this might be a design feature? Not based on real experience though, so might not be a valid hypothesis.

Richard

 

[Rob_Webb]

I assume that the test was with the boat tied alongside or at anchor? That might be an unfair test as once the boat actually starts moving backwards the motion might fully open the prop so this might be a design feature? Not based on real experience though, so might not be a valid hypothesis.

Richard

Correct boat was at anchor. For last time in reverse I asked her to give it a burst of about 10s higher revs and I couldn’t see any discernible difference in amount of opening. You might be right that once actually moving backwards at 2-3 it’s it’s more open but I really need the stopping power when the boat is still moving forwards!

 

[Uricanejack]

Thanks everyone. Amazing response and insights!

Couple of thoughts / updates:

1. Decided to go ahead with purchase of 42DS and sort prop afterwards - is evidently fixeable (pardon the deliberate pun)
2. I know my wish list IS possible - because my current 35ft yacht behaves this way. Has saildrive and 2-bladed folding prop and behaves impeccably. Slight propwalk and obviously less bite in astern than ahead but reverses like a car and turns as well astern as ahead. Therefore this is my benchmark and my ask of the 42DS.
3. Money not an issue so prepared to pay for best folding / feathering prop on the market - I just want to know what that is!
4. Please no more comments about bow-thrusters - I KNOW they help and I will likely get one for next season but meanwhile I want to get the fundamentals of prop performance right.
5. It's not end of season but start of season - summer is just starting here in NZ
6. Boat just lifted and anti-fouled so unlikely to be fouling issue - but I will do a quick lift & hold to check mechanics functioning ok

Finally, this is an interesting review (unfortunately doesn't cover my Volvo prop) but seems to confirm Maxprop 3 blade and Flexofold 3B as v good options:

http://www.yachtingmonthly.com/gear/folding-and-feathering-propeller-test-29807

Your from NZ. That explains it.

Obviously, Prop walk goes the other way in the southern hemisphere.