low is 22.04 so the tide will start back in around 30 mins after so it should be OK to fish
i don't think you would be wasting your time,if you don't catch any fish at least you will have a idea what its like there and know for the next time
some spots fish better on low tide
if you do a search for portmarnock you can see some reports that might give you tips on locations to fish and what bait to use
any time fishing is time well spent