Changing tuttle foil mast angle
Changing tuttle foil mast angle
I thought I would share my experiment in case anybody is interested.
As has been documented elsewhere, some boards with significant tail rocker have their tuttle box angled back (the bottom of the tuttle was set flush to the rocker of the board.) This causes a foil to point down at the front. To achieve flight, the rider has to press down on the tail, which also has the effect of causing the board itself to "plow" through the water. This could hinder the ability of a light-wind take-off. Once the board has left the water, however, the only effect will be the nose of the board pointing up a bit during flight which shouldn't be a huge issue.
It is debatable how much of a problem this really is -- perhaps a skilled rider could still pump and quickly pop up in light wind. I am not yet a skilled rider
There has been some discussion online about adding shims to the top of the tuttle to change the angle. However, it is noted this could damage the inside of the tuttle box as it causes the foil mast to only make contact at 2 points rather than the entire fore and aft surfaces.
I have a 2018 Starboard Hypernut 4-in-1 which has this issue. It appears Starboard has moved the foil box forwards (and presumably changed the angle) on their 2020 model. Some would suggest I try a different board, but I really like the Hypernut for SUP'ing and I love a one-board quiver which I can keep stored in my vehicle at all times.
I have the Starboard SuperCruiser foil with aluminum mast. It was very tight and required sanding to make it fit into the foil box. (Not sure why two Starboard products don't fit together, but I understand this is fairly common...
) As I was sanding the top plastic fitting on the aluminum mast, I got the idea I could remove it and fabricate a new one at a different angle. 
I got some casting plastic and release agent, built a frame to hold the foil mast in the exact position I think I want it, and successfully cast a new plastic foil mast head. I think I will cast one or two more at different angles and then I can swap them at the beach.
Obviously this works well since my aluminum mast has a removable top. If you had a solid carbon mast, I think you could still angle it as desired and add casting plastic (maybe a syringe through the bolt holes?) to fill the voids. I think you would end up with three triangles -- top, front, and back.
As has been documented elsewhere, some boards with significant tail rocker have their tuttle box angled back (the bottom of the tuttle was set flush to the rocker of the board.) This causes a foil to point down at the front. To achieve flight, the rider has to press down on the tail, which also has the effect of causing the board itself to "plow" through the water. This could hinder the ability of a light-wind take-off. Once the board has left the water, however, the only effect will be the nose of the board pointing up a bit during flight which shouldn't be a huge issue.
It is debatable how much of a problem this really is -- perhaps a skilled rider could still pump and quickly pop up in light wind. I am not yet a skilled rider
There has been some discussion online about adding shims to the top of the tuttle to change the angle. However, it is noted this could damage the inside of the tuttle box as it causes the foil mast to only make contact at 2 points rather than the entire fore and aft surfaces.
I have a 2018 Starboard Hypernut 4-in-1 which has this issue. It appears Starboard has moved the foil box forwards (and presumably changed the angle) on their 2020 model. Some would suggest I try a different board, but I really like the Hypernut for SUP'ing and I love a one-board quiver which I can keep stored in my vehicle at all times.
I have the Starboard SuperCruiser foil with aluminum mast. It was very tight and required sanding to make it fit into the foil box. (Not sure why two Starboard products don't fit together, but I understand this is fairly common...
) As I was sanding the top plastic fitting on the aluminum mast, I got the idea I could remove it and fabricate a new one at a different angle. I got some casting plastic and release agent, built a frame to hold the foil mast in the exact position I think I want it, and successfully cast a new plastic foil mast head. I think I will cast one or two more at different angles and then I can swap them at the beach.
Obviously this works well since my aluminum mast has a removable top. If you had a solid carbon mast, I think you could still angle it as desired and add casting plastic (maybe a syringe through the bolt holes?) to fill the voids. I think you would end up with three triangles -- top, front, and back.
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If you knock out the cylindrical nut things (they are press fit) and remove the torx screw from the top, the plastic comes off. It is tight and I had to tap it off, but it is not glued!
Did you find yours was tight, grantmac? I tried old tuttle fins in the Hypernut and they were snug but not too tight. And I tried the foil mast in an old board and it was tight but not that tight. I think for some reason my Hypernut box is a little small and my foil head is a little large and the combination just wasn't great. Before I sanded it, I was worried I would damage the board by reefing on the stupid thing to get it out!
Did you find yours was tight, grantmac? I tried old tuttle fins in the Hypernut and they were snug but not too tight. And I tried the foil mast in an old board and it was tight but not that tight. I think for some reason my Hypernut box is a little small and my foil head is a little large and the combination just wasn't great. Before I sanded it, I was worried I would damage the board by reefing on the stupid thing to get it out!
I'm kind of an edge case in that I built a load spreading plate and am using it in a shallow tuttle board. Any engineer would cringe looking at it, none of the tapers are engaged.
I wish I could buy the flanged mast head they offer on the Freeride. That would give a much better base for my load plate to fit on.
I'm looking at getting a board with tracks and using the DT adapter they sell. Then I'll probably swap a proper foil box into this one.
How stable does it feel with the head you molded? Is the material similar hardness? Casting a proper shallow tuttle head would be fantastic.
I wish I could buy the flanged mast head they offer on the Freeride. That would give a much better base for my load plate to fit on.
I'm looking at getting a board with tracks and using the DT adapter they sell. Then I'll probably swap a proper foil box into this one.
How stable does it feel with the head you molded? Is the material similar hardness? Casting a proper shallow tuttle head would be fantastic.
Ya it seems stable (the connection, not my riding 
...well I haven't ridden it yet!)
Other than some tiny air bubbles, which I understand come from ambient moisture, the material seems good. I have used it once before on another application and it withstood stresses much stronger than what I think it will experience here. This is just going to be compressive forces -- even if it cracks on the thin part, the pieces will have nowhere to go.
So of course after I did this and found the air bubbles, I read that the "fast set" version is much less susceptible to bubbles, so I should have gotten that instead. Oh well. It is from Industrial Plastics and Paints, btw. if you are looking for it. There is such thing as casting epoxy too, I was just afraid if I use that I might never get it apart
Yeah, I don't see why casting a shallow tuttle wouldn't work. If you have a load spreading plate built already maybe you can cast it right-side-up by pouring through the bolt holes. Then you will be engaging all tapers plus your flange, should be rock solid [smilie=beer.gif]
Can you share a pic of how you built the plate?
...well I haven't ridden it yet!)Other than some tiny air bubbles, which I understand come from ambient moisture, the material seems good. I have used it once before on another application and it withstood stresses much stronger than what I think it will experience here. This is just going to be compressive forces -- even if it cracks on the thin part, the pieces will have nowhere to go.
So of course after I did this and found the air bubbles, I read that the "fast set" version is much less susceptible to bubbles, so I should have gotten that instead. Oh well. It is from Industrial Plastics and Paints, btw. if you are looking for it. There is such thing as casting epoxy too, I was just afraid if I use that I might never get it apart
Yeah, I don't see why casting a shallow tuttle wouldn't work. If you have a load spreading plate built already maybe you can cast it right-side-up by pouring through the bolt holes. Then you will be engaging all tapers plus your flange, should be rock solid [smilie=beer.gif]
Can you share a pic of how you built the plate?
The plate was built to just rest on top of a Slingshot Chinook medium tuttle head and make it work in my board. I basically shimmed it to have a friction fit on the SB deep tuttle head. Not really very pretty.
If I were to cast a head I'd probably build a "dam" around it then make the load plate integral if the material has enough strength.
Or I might machine a different load plate which clamps on or engages the tapers to locate itself. I'm not sure the box tapers take that much load if you have a plate to prevent the mast from shifting forwards.
I check my fin box for damage every sail.
If I were to cast a head I'd probably build a "dam" around it then make the load plate integral if the material has enough strength.
Or I might machine a different load plate which clamps on or engages the tapers to locate itself. I'm not sure the box tapers take that much load if you have a plate to prevent the mast from shifting forwards.
I check my fin box for damage every sail.
Flew great today, not totally scientific testing because I didn't have time to swap back to the stock piece before the wind picked up, but I seemed to take off way better with only a 4.5m sail in quite light wind. Either my skills have improved dramatically or it makes a differenceAJSpencer wrote:Nice work! Looking forward to hearing how it flies.
That being said, when the wind picked up I had a few breeches and nosedives and I could see how perhaps an angled up board might crash a bit more gracefully.
