Did you ever try put huge sail on small board,is it possible to sail with this combo?
Generally, it's a bad idea because it's an 'overload'.
You are overloading the board's buoyancy with excess weight from a big rig, but the sideways load when using the correct fin for that board is also too much for general sailing.
Speedsailors may use a relatively big sail on a narrow board but remember that they are also sailing well off the wind.
The symptoms of an overload are: 1) The board feels sinky. 2) The rig feels top heavy. 3) You don't plane any earlier than when using a smaller rig because the power of the bigger rig is hard to direct. 4) You might get the board up to reasonable speed, but it easily drops off the plane due to too much weight and power over a narrow planing footprint..
A lot of people try this, simply because they only have the one board.
A better solution to getting going in lighter wind is to use the smaller rig, but with the sail set with less downhaul, to tighten the leech a bit.
Another light wind solution is to use a bigger/floatier/flatter rocker board - even with the smaller rig.. - so extra buoyancy usually trumps extra sail area.
Manufacturers recommend a range a sail sizes for each size board. It pays to stay within that range.
Manufacturers recommend a range a sail sizes for each size board. It pays to stay within that range.
The sail range quoted by the manufacturer, is among the specs , I would truly believe when they say it has a Powerbox center and mini tuttle sides, three footstraps.The other specs may not be so .
its entirely possible that a range shows 6.0 as maximum, and a 6.5 would be ok, the OP says small board and HUGE sail.
What Basher , has written substantially is correct.
A point exists where a larger sail will have diminished results.
You can get away with a little more oversizing in flatter water. During a Sandy Point trip we did some experimenting and found that a glassy smooth water state helps to keep things in better trim.
Huge I don't know but bigger it works in some cases. Like others stated, flat waters, steady winds. One needs to make sure the fin has adequate torque. Some shapes are better than others. Certain 105L boards can handle 8.0s without issues while others struggle with a 7.0.
So mostly it works when overpowered.
Also the type of sail matters . A full blown race sail will push down much harder on the board than a flat sail.