Changing the prop

[loa]

Hi Gang
I want to change the fixed two bladed prop on my Jeanneau Sunrise 34 to either a two bladed folder or a feathering. "She who must be obeyed" says cost is important..........

The motor is a Yanmar 3GM 30. and the shaft rotates clockwise when viewed from the stern. Boat walks to port in reverse

So the questions are Right or left handed ? Pitch and blade length ? any other recommendations ?

LOA

 

[philip_stevens]

Right handed

 

[ianj99]

Hi Gang
I want to change the fixed two bladed prop on my Jeanneau Sunrise 34 to either a two bladed folder or a feathering. "She who must be obeyed" says cost is important..........

The motor is a Yanmar 3GM 30. and the shaft rotates clockwise when viewed from the stern. Boat walks to port in reverse

So the questions are Right or left handed ? Pitch and blade length ? any other recommendations ?

LOA

Kiwi prop is what you need. Just had one fitted and much better than the previous fixed 3 blade one.

http://www.kiwiprops.co.nz

UK distributor is Vecta Marine.

Performance astern is transformed though the pitch needs adjusting in the Spring (easily done by a screw on each blade)
I

 

[Norman_E]

It sounds like a right hand prop. Getting the right size and pitch is vital, so you need to know your gearbox ratio and maximum power revs of your engine. I think you also need to look at your current prop and discover its diameter and pitch, then ask yourself whether your engine will run at full power revs with that prop, at full throttle, or does it want to over-rev? Once you have all that information I suggest you talk to Darglow Engineering who make their own three blade feathering prop, which is one of the more reasonably priced feathering options. Darglow also sell the Danish Flex-O-Fold folding propellers. Their advice to me regarding diameter and pitch was spot on.

Another feathering option is the kiwiprop. A two blade folder will almost certainly be cheaper, but it might not be so good going astern as a feathering one.

 

[yoda]

First thing to do is work out what prop you should have. The one at the link below is generally well accepted.

http://www.castlemarine.co.uk/pitch.htm

What is important is to swing as big a prop as you can but without getting the blade tips too close to the hull.

Yoda

 

[Tranona]

There is a huge range of folding and feathering props and your choice will depend on what you are trying to achieve and the price you are prepared to pay. Simple 2 blade folders are under £1k, and some feathering props in the size you need are as much as £4k.

There have been reviews/tests in YM about 2 years ago and ST earlier this year which give you an idea of what is on the market and the pros and cons of each type.

Once you have decided on which type and make, the supplier will provide the recommended size based on the data of your boat. This may well vary from design to design, so don't decide on a size yourself, although checking your current size (it will be stamped on the prop) is useful, and as suggested you can get a ball park size from the Propcalc programme.

 

[ianj99]

This site has a boat speed calculator which works pretty well so you can see whether the results from the castlemarine propcalc program are realistic.
(they were for mine)

http://www.psychosnail.com/boatspeedcalculator.aspx

I