That is the whole problem.
I was very surprised to make that speed against what I expected to be a strong ebb current.
This is a 24' boat that probably can only do 6 in perfect conditions.
Maybe it is as simple as that. I had perfect conditions and was making 6 through the water and 3 over ground.
That may be the answer.
I guess that is what I was implying.
Your position looks like you were approx. 1/2 mile north (m) of race rock and west of the tip of Fisher's Island ( race pt.) In about 50 to 80 ft of water. I've never been in that particular spot, so can't offer local knowledge re the strength and direction of the currents in that exact spot. You may have been out of the strength of the ebb. There may be eddys?
I usually pass through between race rock and valiant or valiant and little gull where, as you know, depths are over 200'