Hi everyone.
So after reading all about mast shimming… I’m lost!
Here’s my issue:
I have an Armstrong regular mast ( not high performance ) so neutral angle. I made a 1 degree baseplate shim to nose-up the board ( so spacing the front bolts ). It worked really good on my previous foil , making it smoother to ride more even foot pressure, easy smooth takeoffs. I changed to a HA foil ( the one I always wanted ) and I’m having issues because the board is always pointing up while riding and pumping and also when taking off or doing a turn because as I slightly press with the back foot it ejects me up… What am I supposed to do now? Get rid of the shim or actually make it bigger???
Please help , don’t want to waste an all other session trying adjustments
Get rid of the shim or put it at the back of the mast. That will drop the nose down while riding and make pumping easier.
Will that also stop the board from ejecting up when starting turns and taking off?
No , that will actually make that worse , you need to slide your mast back or reduce the tail size or tail angle with a shim to stop the boosting on takeoff
Baseplate or board shimming, only does 2 things……changes the riding angle of the board while up on foil (nose up or nose down). The second effect it has is only during the takeoff phase. The board is forced to stay level with the water surface ,so a front mast shim will point the foil rig down delaying takeoff and reducing boosting.The opposite will happen by shimming the back of the mast, the rig will be pointing up and get on foil quicker and cause earlier lifting.
What was size was the old foil and what size is the new HA foil.
Old foil MA800, new foil HA725
But it’s crazy because with the older foil , same shim, it didn’t feel like the board was pointing up while riding and had no issues
And that was what I wanted to avoid, to move the mast backwards because then it doesn’t turn as good
That makes sense , all the MA foils nosedive unless paired with one of the newer tails and ridden further forward in the tracks. My 1125 HA rides 50mm further back in the tracks than the 1750 MA foil both using the 180 speed tail.For some reason the MAs need to be further forward in the tracks and need to paired with the newer tails that have camber and more down push. I don’t know for sure but I suspect the built in AOA of the MAs is less Than the HAs to keep the speed up ,as they are fast foils for a medium aspect foil.
Also, a pro foiler I follow says he uses the ha725 with a small tail, no shim in the stab and nose-up shim on the mast of 1 degree. I suppose he has a high performance mast that is already tilted 1 degree. That means he’s on a 2 degrees nose-up shim!.. But don’t see his board pointing up that much!
Ok and now I’m more confused… So what you suggest to do ?
His board might not have much tail rocker so he needs more mast shim. I run the 725/180/50 red shim on PM 795 at 4 on FG 4’5 and it’s perfect. IF I use my 7’3 DW Sunova board that is flat in the tail ,I use a 1 degree mast shim as well as the PM mast to get the nose up while on foil.
If your setup with the MA 800 was balanced but is too lifty with the 725 and you don’t want to move your mast back ,then the only option you have is to use the smallest tail you have ,and then more add tail shims if you want to reduce lift even more ( red + blue ) otherwise you have to slide your mast back further which is what most people find.Forget about the mast shim until you solve that problem first , then if you want to change the board angle while on foil then play with the mast shims
Thank you, really appreciate your help
My board is a Freedom Foil Board 3’10 Techno model 30L
What about two red shims in the stab?
Does changing the ride angle of the board on foil to nose down also angle your body forward or do you bend back leg or move feet back to compensate?
You can use 2 red shims with the tail no problem