Hi everyone
Is 85cm too wide a board for and efoil? Got a RRD Xfire 129L on my hand. It is 85x229cm, and has a deep tuttlebox for easy foil attachment.
Hope some has an opinion About this?
Perfect for a Windfoil, IMHO not so good for an efoil and this for different reasons:
1- there are 2 or 3 deep tuttle standards in the world meaning that the foil you’ll buy might not fit or stay into your board DeepT box (too much or not enough play),
see, for example the Gong Catalog
2- you cannot make the necessary space for the 3 8AWG wires (+ optional water cooling) in such a head without making it very fragile for an efoil use
3- a deep tutle box is usually stuck between the deck skin and the bottom skin meaning there might not be enough foam thickness to recess your wires under the deck. Therefore they might have to run above the board deck at best under a piece of scotch tape.
4- deep Tuttle masts = for 2018 and before, very often plain carbon (not hollow) that cannot receive your 3 or 4 wires
The toughest solution and most convenient is THE PLATE: either
1- drill and reinforce 4 holes like @michion in
2- ahead of your deep tuttle box, install 2 US boxes inside the board ensures you can hide the cable under the board skin and through the plate then the mast. For this reason, +/-100% of the commercial brands and 100% of the DiYer have adopted the … plate
3 - a risky solution might be to adopt a deep Tuttle to plate adaptor (200USD) with the risk n° 1 seen above (brand = Takuma or Zeeko ?, …) Like that you can fit a plate that will welcome a hollow mast (forged carbon or aluminium). I consider it risky because of reason #2 here seen above.
[Edit] I have just found this promising solution: The Chinook Power Plate that you can reproduce at home for 20 USD instead of 200. You still have to find a way to pass the 3+1 wires into the mast 
Power Plate Foil Adapter
If you have a windsurfing board with a power box fin box that you want to use with a foil, this is your solution! The Power Plate adapter will mount to any foil that uses a 4 bolt style plate and allow you to put it in your board that accepts a power box fin. This is an excellent solution for anyone who wants to give foiling a try, without investing in a whole new board.