DRAGONFLY Trimarans User Forum

Has anyone changed their original Gori 2 blade folding propeller for another brand and if so, are you happy with the result?

I have a 15 x 12 RH prop which is mechanically ok but it sure vibrates a lot when I have to motor at cruise speed (2500 RPM). If I sit at the forward end of the cockpit, there's a little engine vibration, but if I sit at the aft end of the cockpit it's downright uncomfortable!

I'm not a propeller expert, but I suspect those almost square edges on the blade tips may have something to do with it.

A little more pitch might also help as the engine will generate 3450 RPM with no black smoke in the exhaust while the boat is still tied to the dock.

I haven't pulled the hub and had the prop balanced, and don't know if that would help or not.

I'm interested in a Flexofold and am hoping it might be a little smoother running.
As I sail 95% of the time, motoring efficiency comes behind non vibration in my book. Low drag is important.

Any comments are welcome.

Steve B.
Flexible Flyer DF1000 # 15

Steve;
I usually only develope a vibration when the prop is dirty or at the end of the season the anode on the shaft starts to erode, creating an ever so slight inbalance in the shaft. That would lead to a vibration. Check there first, anodes are a heck of a lot cheaper than props!
Ted

Ted,

Thanks for the reply, but that's definitely not it. I converted my shipping cradle to a tide grid behind my dock so I can clean the bottom etc. any time I want.

I pressure washed the bottom and renewed the collar zinc just last week.

Steve

Hi Steve, I found out the story from the people who auctioned the boat off as an insurance write off. Yes big holes. I will measure the mast tomorrow when we fly down to see it, but somewhere I saw it supposedly had the taller mast. Hopefully it rotates also. It is aluminum. Is there anything else I should look for like damaged joints in the swing wings, or centerboard ,rudder damage. The shaft was certainly bent. The foam core was replaced.
Thanks,
Derek

betsyderek wrote:Hi Steve, I found out the story from the people who auctioned the boat off as an insurance write off. Yes big holes. I will measure the mast tomorrow when we fly down to see it, but somewhere I saw it supposedly had the taller mast. Hopefully it rotates also. It is aluminum. Is there anything else I should look for like damaged joints in the swing wings, or centerboard ,rudder damage. The shaft was certainly bent. The foam core was replaced.
Thanks,
Derek

If it still has the original mast it is carbon fiber and it is the taller mast,and does not rotate (it is round).

As for other things to look for, the pictures and comments in the other thread on this boat should give you a lot of info.

Steve - I never solved my vibration problem when I had the 1000.

Not in order: I tried a 2-blade Vari-Fold, a 3-blade Volvo Penta, replaced the shaft, replaced the cutlass, added a Flexible Coupling, aligned the engine.