Inspired by the posts about the highly modified NP foil i decided to make my own extension because i also think the standard pink NP foil is very fast but also very unstable. I made 3 attempts. First one out of aluminium but i think the aluminium is not strong enough for the bolts and i think they will not hold in the end. The second and third one i made out of a bar of stainless steel. I made one of 20 cm and it worked well. The only thing was that after sailing for an hour the bolts became a bit loose and a bit of slack of the extension was the result. The third one is 15 cm and very close fit so no adapting possible anymore but also no slack at all. I gave the backwing quite a bit of lift bacause i also think the standard foil has to be sailed with a lot of backfoot pressure.
You do not need any specific skills to make it and it is low cost. (around 30 euro)i tested the extensions last friday in wind of 15 to 18 knots and made my first run over 50 km/h with it so it really works
As soon as i can upload pictures here i will do so.
One of the guys I sail with made a foil extension from an old broken carbon boom tail. Works really well and is very streamlined.
Select to expand quotespeedfoilrob said..
Inspired by the posts about the highly modified NP foil i decided to make my own extension because i also think the standard pink NP foil is very fast but also very unstable. I made 3 attempts. First one out of aluminium but i think the aluminium is not strong enough for the bolts and i think they will not hold in the end. The second and third one i made out of a bar of stainless steel. I made one of 20 cm and it worked well. The only thing was that after sailing for an hour the bolts became a bit loose and a bit of slack of the extension was the result. The third one is 15 cm and very close fit so no adapting possible anymore but also no slack at all. I gave the backwing quite a bit of lift bacause i also think the standard foil has to be sailed with a lot of backfoot pressure.
You do not need any specific skills to make it and it is low cost. (around 30 euro)i tested the extensions last friday in wind of 15 to 18 knots and made my first run over 50 km/h with it so it really works
As soon as i can upload pictures here i will do so.
Hi Rob. I too was inspired by the highly modified thread. Because I have the newer model I was unable to do it the same way as you. I cut my fuselage and added in 20cm using carbon rod and a piece of boom. I was surprised to see how thin the carbon is in a couple of places on the fuselage, so with the extra leverage of the extension I would suggest putting a couple of layers of carbon over everything once you are happy with your set up.
Here are a few pics of how I done mine.
Holding up well so far so next winter I will look at moving the front wing forward by 6cm making it 105cm from front to back edges of wings. It is way more stable as it is but I have to put the mast base a fair way back in the track and would prefer it further forward.
If anyone in Australia wants to borrow the mold feel free to message me. 
Nice job, Swindy, the mold is impressive.
The layup on the fuse looks less even than I would have imagined. At least the part that gives it vertical stiffness looks solid but the top and bottom look like the layup shifted around before curing. I hope that same factory isn't making bike frames and forks.
Some of the older NP/F4s are selling pretty cheaply. Good to see them modernized and staying useful.
Select to expand quoteSwindy said..speedfoilrob said..
Inspired by the posts about the highly modified NP foil i decided to make my own extension because i also think the standard pink NP foil is very fast but also very unstable. I made 3 attempts. First one out of aluminium but i think the aluminium is not strong enough for the bolts and i think they will not hold in the end. The second and third one i made out of a bar of stainless steel. I made one of 20 cm and it worked well. The only thing was that after sailing for an hour the bolts became a bit loose and a bit of slack of the extension was the result. The third one is 15 cm and very close fit so no adapting possible anymore but also no slack at all. I gave the backwing quite a bit of lift bacause i also think the standard foil has to be sailed with a lot of backfoot pressure.
You do not need any specific skills to make it and it is low cost. (around 30 euro)i tested the extensions last friday in wind of 15 to 18 knots and made my first run over 50 km/h with it so it really works
As soon as i can upload pictures here i will do so.
Hi Rob. I too was inspired by the highly modified thread. Because I have the newer model I was unable to do it the same way as you. I cut my fuselage and added in 20cm using carbon rod and a piece of boom. I was surprised to see how thin the carbon is in a couple of places on the fuselage, so with the extra leverage of the extension I would suggest putting a couple of layers of carbon over everything once you are happy with your set up.
Here are a few pics of how I done mine.
Holding up well so far so next winter I will look at moving the front wing forward by 6cm making it 105cm from front to back edges of wings. It is way more stable as it is but I have to put the mast base a fair way back in the track and would prefer it further forward.
If anyone in Australia wants to borrow the mold feel free to message me.
first class job swindy, love the mold system
Looks like a guy named Craig lunn is also experimenting with extending the fuse of his NP foil. Is he also on this forum?
Perhaps he can tell us how he made it work for him because he is going very fast with his foils too.
Select to expand quotespeedfoilrob said..
Looks very good and how is it sailing now, big improvement ?
Having used it several times now I am happy with the increased pitch stability. Way less twitchy than it was before. Also easier in gybes. I think I will move the front wing forward 6cm in the future but will leave it till next winter.
Yes, Craig has extended his both forward and back. Haven't seen it yet but hope to catch up with him soon.
