I’m adding a hydrofoil to the SUP I made (thanks guys for the help a few years ago when I built this) and no matter where I look I can’t seem to figure out just how much reinforcing you need to add a hydrofoil to a SUP. I was going to add an aluminum plate a few square feet where the mast attaches and then just outside that maybe add a skin of sheet aluminum with fiberglass. Anyway, suggestions please. I can’t seem to get a handle on how much stress this will add to my SUP.
I would look at these sub-forums of Standupzone for the information you seek:
https://www.standupzone.com/forum/index.php?board=88.0 the Foil SUP section
https://www.standupzone.com/forum/index.php/board,11.0.html the Shape Shack for SUP
I would skip the aluminum and stick with composites.
EDT,
I know you have many options on getting advice and I would like to thank you for choosing swaylocks for the best bad advice.
Need more info. Regarding your foil MAST plate. Is it standard size with M8 holes at 3 1/2" center or not yet drilled?
Your plan of aluminum plate is over kill and unecessasary weight and expense.
This would be suffiecient.
What board brand and dimensions will you be adding foil too?
Do you have tools and have you ever placed an eleven inch center fin box?
Your want to rout out wider and longer than your center futures fin box to place in 7.5-10mm of high density foam or wood theckness into foam. 4" wide is perfect for each side or if no stringer is present going laterally to center box is ok also.
PM me for specific details on how to glue in with epoxy resin and milled fibers with weights on top of high density foam or wood reinforcments.
Standard plate holes are 3.5" on center and an M8 hardware center box nut is used with an M8 1.25" length bolt with and oval or flat head on bolt.
As a last resort you can also make a non compatable set up if your plate is not standard industry specifications. PM pics and I can give you details on how to acheive.
aloha
Mahalo for the replies Charlie. I loved the opener about ‘thanks for choosing’…
Yes, if OP adds some details it could be one-stop Sways shopping.
Thanks bb30. Great job on your mast adapter. Yeah my mast plate is standard size. I’ll take your advice I think, and just make a patch like you have in the photo. Don’t have any carbon, so I’ll use fiberglass. My sup is short, 8 and a half feet, but very wide, lots of flotation just glass foam and epoxy with a stringer and a few fin boxes I cut out and put in. If I had to make another SUP I would make it cut through the water a lot easier, but what hell I thought I was having a genius idea when I made it. Should be great for a hydrofoil because it doesn’t have a lot of swing weight.
Sounds like you have all the tools then. Carbon not necessary but high density foam or wood planks 10mm or thicker under the new fiberglass would get the lateral stiffness you need. A futures center box with flange and pre glass installation would be best but not necessary. Also if your SUP has lots of tail rocker or concave at new plate location, you need to get this flat so your foil rig is flat also. So I get the insterts of HD foam or wood placed and glued or epoxied in. Careful not to exotherm your foam with resin. I use milled fibers mixed in to resin to tooth paste consistency to avoid exotherm. Percise cut out of foam and reinforcements keeps down the the amount of resin you use also. I place a piece plastic over insert and put a weight on the incert for the 1 hour or so curing time of epoxy.After reineforcement insert set and dried I sand flat to board. Place pre glass fin boxes, futures if possible. 3layers of 6 ounce over patch and boxes. Sand and go surfing. I am totally new to the SUP foiling but have friend who is balls deep into it and I am paying attention to what he is doing. What I do know is how to reinforce 1 lb foam under fiberglass. Seems like you are knowledgable enough to figures things out.
When you make a new foil SUP or buy one every thing is getting shorter and still keeping volume with thickness. Board lengths seem to be under 7’.
Attached pic of milled fiber to help decrease exotherm
Wow great detail thanks!
BB30, where did you source the carbon mast adapter? I’m only seeing heavy aluminum. Many thanks
all the best
Hi Greg,
Mast adapters are foil specific. This was made in a mold for a prototype foil. You could make your own for your foil mast pretty easily with out a mold but vac bagging would be necessary. My masts will have a built in composite plate system that is not removable. Working on quick release to board without screw mounting each use. Started project in June 2017 and just recently have been able to work on it again. Do you Foil also? Prone, SUP,Tow in?
aloha,
Charlie