Faster on Port

It all starts due to the nature of how wind and gusts are formed. As I presume you all know, wind blows roughly along isobars, however due to the friction caused by land and sea the wind is slowed down and therefore is altered to blow a slightly more direct rout between the high pressure and low pressure. This results in the wind blowing 15 degrees off the isobaratic/gradient wind over the sea, and due to larger friction, 30 degrees different over land.

A large number of gusts are where for some reason the stronger higher altitude wind has found it's way down to ground level, therefore will be from a slightly different direction that will favor one tack more than the other. This especially applies to micro gusts (lasting less than a second and often found about the height of the top of the mast). This means that on one tack you will effectively be given tiny lifts every now and then that will give you slightly more favorable winds without you especially being aware of it.

hope I explained this well enough for you to understand

I always feel like I struggle on starboard and am much faster on port. Then I look round me at what other boats are doing and realise that actually i am doing just fine and then concentrate on what I should be doing than my perception that there is a problem.

As others have said though definitely worth checking the board and rudder alignment out and measure from the mast head to the transom corners as well as the over all rake. It is unlikely to be the boat though. The only real Blaze 'issue' that I am aware of is the join of the hull/deck in at the front of centreboard case which has a tandancy to separate on the early Mk 2 hulls (654 and upwards).

 

What if the wind direction is slightly different further up the mast? Let's say the wind is blowing from true north at deck level, and this is what you sail to as per your tell tails. But if you go up 20 feet and the wind there is blowing at (say) 010 degrees then assuming there is a bit of twist in your sails you will have a rig that is spot on whilst on starboard tack, but on port the top of the sails won't be driving at all as they will be nearly backed.

 

Your upper leach tell tails don't help that much here - on the bad tack they will flow really freely anyway as the sail is nearly head to wind. On the "good" tack the top tell tail might stall when the sail is overtrimmed but if you are anything like me you don't tend to look at them as much when the boat feels like it's going well - it's when it isn't you start fiddling with stuff!

 

We noticed this as we spotted a clear pattern of shifts in the gusts which usually implies that the wind direction higher up is different to that at the water level - only in the gusts does this true wind reach down to you, whereas in the lulls obstructions at ground level deflect it.

 

If the problem persists, or continues in stronger winds then simplest way forwards might be to swap boats with someone else?