Hunter 340 2 or 3 blade prop

[John]

Hi there I have a 1999 hunter 340 with a 27 hp yanmar it is fitted with a 2 blade prop , will a 3 blade prop give me significantly more thrust and bite especially astern , we operate mainly in the english channel where there can be occasions when plugging into seas under motor is needed. Why do they fit 2 blade in the first place?, will a 3 blade on this boat adversly affect the sailing performance .what size 3 blade prop should I use? any advice appreciatedthanks out there in advance

 

[Paul]

3-blade props overrated?

I have a 1995 336 with the same engine and probably the same 2-bladed prop.Your current engine and prop configuration will drive your hull at its maximum speed at moderate rpm. What else is there after that? With a 3-blade prop you may reach hull speed at a slightly lower rpm compared to the 2-blade prop, but the engine will have to produce more torque to do so. As for backing, many people report that three-bladed props exhibit less prop walk. This may be true, but I don't think that is desirable. With practice, helming a boat is easier with pronounced prop walk, since the effect allows for tighter manuevers than would be available from the rudder alone.

 

[Chuck Wayne]

2 vs 3 bladed prop

read the archives, there's been a lot of discussion on this. basically, a fixed 3 blade will give you hull speed at a lower rpm, and give you more control, especially backing, in a current, or in heavy seas. you will lose 1/2 to 3/4 kt under sail from the extra drag. contact hunter for the specs, or any good prop shop, for the correct prop for your boat

 

[Kevin]

more eff.

Hello John,Sorry I missed your note. I only saw it this AM when I was looking at past posts. You will see an increase of apx. 30% when you move over to a three blade. This will help you to maintain speed when you are confronted with heavy winds or seas as well as increasing your efficiency astern. You will suffer sailing speed and that could be equal to about .3 knots in medium air. Hope this helps. Kevin