I recently purchased a hunter 40 legend with a yanmar engine that has a fixed 2 blade. It backs horribly. My previous Catalina 30 with a martec 2 blade folding backed well. I was shocked at the difference. So my question is what size and pitch are recommended? The advantages of 3 blade over 2? I'm hoping to find something used as the boat is also in need of a complete interior.
Folding prop recommendations 85 Hunter 40.
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Welcome @85bittersweet to the forum and congrats on your new larger boat.
That your new boat backs differently is no surprise.
Look at the differences in the hulls
Catalina 30
Hunter 40
Of specific interest to your challenge in the location of the prop to the rudder. By locating the prop closer to the keep as water washes over the keel in the 30 it tends to reduce the tendency for the boat to change direction. Being "less" responsive more like a Cadillac than a sports car (the Hunter 40).
The Hunter puts the prop near the rudder and farther from the keel. So you loose the stabilization of the keel and get the more reactivity of the rudder. Small movements become exaggerated by the prop wash.
How I would deal with this design in the Hunter is to use small rudder changes and pulse the prop power. Get the boat going then pop the boat into neutral and coast using the small rudder changes to change direction as the boat coasts backwards.
Or you can go higher maintenance/cost and install a bow thruster and use it to counter the steering of the rudder direction changes. This would require a whole new set of skills but you could actually learn to push the boat sideways as you becoem proficient.
When you can, go out and practice the backing before you spend a lot of money on new props hoping for a magic solution that may never happen.
That your new boat backs differently is no surprise.
Look at the differences in the hulls
Catalina 30
Hunter 40
Of specific interest to your challenge in the location of the prop to the rudder. By locating the prop closer to the keep as water washes over the keel in the 30 it tends to reduce the tendency for the boat to change direction. Being "less" responsive more like a Cadillac than a sports car (the Hunter 40).
The Hunter puts the prop near the rudder and farther from the keel. So you loose the stabilization of the keel and get the more reactivity of the rudder. Small movements become exaggerated by the prop wash.
How I would deal with this design in the Hunter is to use small rudder changes and pulse the prop power. Get the boat going then pop the boat into neutral and coast using the small rudder changes to change direction as the boat coasts backwards.
Or you can go higher maintenance/cost and install a bow thruster and use it to counter the steering of the rudder direction changes. This would require a whole new set of skills but you could actually learn to push the boat sideways as you becoem proficient.
When you can, go out and practice the backing before you spend a lot of money on new props hoping for a magic solution that may never happen.
The purpose of a folding propeller is to reduce drag when under sail, not to improve maneuvering. Of course a three blade propeller will help back the boat better and the folding feature will greatly reduce the added drag a fixed three blade would impose. Stick with the size and pitch of your two blade or the corresponding conversion of the prop manufacturer.
I will try that, a friend has same boat with a 2 blade feathering prop that backs up nicely. The prop was painted so many times you can't read the numbers on it. Next time I'm at the yard I will take a picture. I was told folding prop's have less prop wash
It goes where I want it to go. I sometimes put it in neutral momentarily to counter the natural port prop walk and then put it back in gear with complete control. The large spade rudder I think helps greatly. If I have a choice with slip assignment I request stern in port side to but I can handle starboard side to with a bit more thought.
I would highly recommend a 3 bladed max prop. On a larger boat, 4 bladed vari prop.
Just to elaborate,,
I firmly believe you are far better off with a feathering prop than a folding prop. There are many posts coo-berating this. The feathering prop does not have issues re: opening, if you get into a weedy area.
I had the 3 bladed max on my 40.5, and it was a perfect match for the size of boat.
With the feathering, it will deploy in idle rpm, which folding can be dicey with.
Whatever you do, don’t go with 2 blade on a 40 footer. I had a 2 blade on my prior 33 footer, and it was marginal.
My three blade flexofold opens at maybe 1/2 revolution. I filmed the operation with a go pro. If the max prop ever needs to be rebuilt, and some do for various reasons, that certainly is not free. Also the folder is less expensive. In the end, Ford Chevy. Max prop, flexofold and variprop are all quality builds.