Future Cherub

[daryl_wilkinson]

I think the really interesting thing in that report is...

When foiling, the boat is much more stable and easier to sail than a conventional R.

There has been plenty of outside speculation that "the boats will be harder to sail" on foils. It turns out that the R on foils is actually more stable and much easier to control. It didn't take long to acclimate to the decrease in lateral resistance from the much smaller vertical main foil, and stop falling into windward when wiring.

[Banshee Ambulance]

It is interesting that the R Class rejected T-foils as they were too draggy downwind. I hear the 14s are starting to question them as well. Is it just because the cherub is so short they are of benefit to us?

[roland_trim]

It may well also be a function of flat. The T-Foil only gives a massive hit when the mast is bolt upright - from looking at the piccies this is not the case downwind with their rigs?

[Will_Lee]

I hear the 14s are starting to question them as well.

Can you post a link about this?

[daryl_wilkinson]

here's the link to the R's foiling history http://www.rclass.org/info/construction/hydrofoils/hydrofoil-project

[daryl_wilkinson]

It may well also be a function of flat. The T-Foil only gives a massive hit when the mast is bolt upright - from looking at the piccies this is not the case downwind with their rigs?

I think it is more to do with the fact that they have a clear and unrestricted aim of making the boat as fast as possible. Given that there skill level is high by virtue of sailing in consistently high wind strength and use of larger kites negates the need to damping downwind for extra speed from control. The gain upwind did not benefit them downwind. So it was logical to move to a fully foiling boat, which has significant advantages in speed up and downwind as well as damping for improved control.

[Banshee Ambulance]

I hear the 14s are starting to question them as well.

Can you post a link about this?

Haven't read anything as such, just the chat I hear from folks in the uni club. May be rubbish - I don't know.

[ross_burkin]

It may well also be a function of flat. The T-Foil only gives a massive hit when the mast is bolt upright - from looking at the piccies this is not the case downwind with their rigs?

I'm not sure how the mast position effects T-foil speed advantage (unless you mean capsized and not capsized). If the R's sail more bow up than normal then they would just change the angle of the foil relative to the water.

[Phil Alderson]

The 14's are not allowed to trapeze behind the transom so there is limited scope for setting the T to lift down wind.

[phil_kirk]

They also have 2 feet more hull in front of the transom so gain all the benifits of controlability from the extra waterline length.

[roland_trim]

I'm not sure how the mast position effects T-foil speed advantage

I'm not completely sure how this works myself. But the foil on Born Slippy certainly only seems to give use a boost when the mast is not leaning too far left/right.

A stab:
The lift from the foil acts along the line of the rudder blade. If the boat is healed then some of that lift then starts working against the back of the hull steering the boat (sin30 ~ 0.5) and needing to be corrected. The loss of lift is only small (cos 30 ~0.87), but there appears to be a whole load of extra drag. I'm sure the theorists out there can reference the reason, although it may have nothing to do with this and simply be a function of the slug hull shape.

[Banshee Ambulance]

How would the L3s main spray rail count as a chine with respect to our rules? Im thinking of scaling the L3 for a new boat. Where would the chine beam measurements be taken from if its a spray rail rather than a chine?