You need to come up with your own code that everyone on the boat understands. Try to keep it to one handed signals (it's hard to stay on the pointy end when you can only use one hand, it's really hard when you busy doing sign language). Don't specify pinky, or index to mean different things. In gloves you can't tell the difference between an index finger and a ring finger. Just refer to the number of fingers up.
Thumbs up/down = come up/down
Arm/hand straight out = hold course
# of fingers shown = boat lengths to the line
Crossed forearms = over the line or 1/2 a boat to the line, you pick.
windmill motion w/ arm/hand = speed up
others can be made to fit whatever you need them too. Just remember that the bowman has the best view, and make sure the crew and skipper know this, and trust his/her judgement.
Merit 25 # 764 "Audrey"