There was an earlier post on tandems at Sandy Point, but I couldn't resurrect it, so starting a new topic. We will need to get this one out on the water again:
Very nice Perks. The fin set up is exactly what we were thinking. Daffy and I hit 35 with his at the Pit but no joy at LG. Just couldn't get the fin out of the weed enough to get going. I'd be happy to jump onto the front with you.
Geez Perks, you're not just a pretty face! That looks awesome and the fin setup....genius.
Dave loves a tight hole apparently 
Now my brain is ticking over.
2 ideas.
1/ Front guy gets more vertical lift from sail, by raking more to windward than usual? Should reduce whetted area.
2/ a stepped bottom, so there are 2 planing areas, fore and aft. I think there was a boat made like this so there was always a 7deg angle of attack, almost independent of weight distribution. Not sure how you'd turn it though. might need a turning flap on the fin.
I was wave sailing at Lancelin with a mate in the 80's. We were dicking around one the way back to the beach and I sat on the nose of his board. The acceleration was surprising.
I dig the vid
aussie speed sailors seem a breed of their own, cool to see the legendary ones mugs speak.
Select to expand quotedecrepit said..
Now my brain is ticking over.
2 ideas.
1/ Front guy gets more vertical lift from sail, by raking more to windward than usual? Should reduce whetted area.
2/ a stepped bottom, so there are 2 planing areas, fore and aft. I think there was a boat made like this so there was always a 7deg angle of attack, almost independent of weight distribution. Not sure how you'd turn it though. might need a turning flap on the fin.
Hi decrepit Yes it got to the plane easy And accelerated well but when it hit 30 knots it tended to die and then try to come Back again ,not sure why
Select to expand quotered said..
Get Izaak on the front ... fastest father/son duo in Australia!!
Yes Red He was on the front the first time but tough to get him back there
Select to expand quoteanthony perkins said..
Hi decrepit Yes it got to the plane easy And accelerated well but when it hit 30 knots it tended to die and then try to come Back again ,not sure why
That sounds like the old negative rocker problem, too much lift behind the centre of gravity pushing the nose down.
But in this case, you don't need -ve rocker to do that. you have all the weight of that front sailor.
That's why I think the front sailor needs vertical lift, either the stepped hull idea or a more raked sail. In this day and age though a foil may work. You need somebody smarter than me to work that all out.
I read somewhere a long time ago, the American navy worked out, the fastest setup for planning hulls was a 7deg angle of attack. That means the faster you go the less hull is in the water, so less drag. So if it was me experimenting. I'd modify the bottom with some extra foam under the front rider's feet at 7 deg. Just how thick that should be, would need to be worked out. I guess so that when planing on it, the rear planing are would be optimum as well. All about getting front and back whetted area's minimal.
