Yes the hull plane is very different depending on which tack. Once we were hiking out or sitting in and moving along we had it just skimming. The nose rises even in just a reach and the ama lifted up some as well. The underside of the float is a shallow v to give us some planing potential and immediate bouyancy as soon as it hits the water but it seems to have enough shape to reduce slap. Did high side it once when couldn't release main sheet quickly enough but gave us laods of time to control it and it didn't go over. It was 30 knots gusting up to 35 knots wind though and we were heading back in as that was a bit much for us.
As a side note to this jolly discussion, I am part way through building my test bed ISO dinghy based trimaran.
I only have one side made up and usable so I guess it is currently a tacking proa?
The trampoline frame slides in and out for easy storage in a dinghy space and it has two vertical bolts that lock it in place through the internal box frame.
The wind was very swirly and all over the place for this short test but it gets a shift on and the stability and feeling of security is very good and confidence inspiring. I need to get the outrigger sanded and painted asap as just epoxy at the moment and then make the other side.
I'm going to change the design of the next float to compare performance - adding some extra volume and changing the shape but keeping the slender entry point. Further on, I will also make some much smaller lighter floats for when our technique has improved to lighten things up. Finally I will replace the ISO hull with my own designed hull as it is quite weighty and to add various features for our intended fast cruising requirements.
The newly welded up frame feels pretty rigid and the home made tramp is working well - I can lie down in comfort or hike and my wife can hike out nicely. I've added a cam cleat for the main sheet on the tramp frame for me and I will add a further one for the jib and hopefully we can get testing the trapezing option as well next time.
Unfortunately we had no phone or GoPro again but hopefully next weekend we will be more organised if the weather is any good.
We also had to sail back in head to wind down the river and mildly against the tide and the easy tacking with good stability in shifty gusts was great. Still a bit hairy for us as we are very inexperienced but shows we have nothing to worry about.
The only GPS run we have had had 11 knots on a reach in low winds and we won't use the spinny until we get the other side sorted. It should fly once we get confident and sort the set up.
All in all I'm very pleased: speed and safety for not a lot of cash.
In the interim as time is tight to make next frame and float I might just make a little wing extension to get more leverage when hiking out and trapezing.
did the hull plane differently depending on your tack? Does your main hull rise at the nose on plane? How does that effect the ama?
What does the flow around your ama look like at 11k? Does the ama look like it is planing?
We ahve no ability to reef with that sail currently so I am planning on putting in 2 sets of reefing points so we can safely go for longer day trips - round the Isle of Wight etc and not be worried about being caught out as conditions in the Solent can change pretty dramatically. If it works on this crap old sail I will then put them in on the 2 like new sails I got with the boat.
Here is a video from a different test in low winds at Mudeford from January 2nd the - frame was just temporarily rivetted for speed but gave us an idea that the dimensions were about what were after.
It gives a bit of a view of the wake from the outrigger at various points and speedds but that was with it sat pretty heaviliy in the water as although the verticals were shorter we were not making any effort to balance things up as no hiking strap leta lone trpaeze at that point.
The inside crossbeam will be removed shortly as now not needed and will save a few kilos.
The float is under 20kg and we are pretty light at 55kg and 75kg so I'll check frame and tramp/frame weight to see the new total but we are probably still lighter than quite a few crews....
The angle of the float has changed since then and we need to get hiking for balance. As my wife is so small, we can safely both trpaeze off his mast apparently which I think will be great
We could look at taking some weight out of the floats - it is rammed with plastic bottles and so on for safety bouyancy to ensure my wife was happy we were not going to sink horribly.... Keep some but what she doesn't know etc...
End goal is to d osome safe, fast solo coastal trips.
If I am allowed : )
Finally got good wifi and I have watched the video. Looks great, development to do sure but potential in buckets