When I teach beginners how to windsurf I usually have them grab the mast with the front hand first as this helps maximise their control over the rig. Then, once they get better and start really leaning backwards into the wind I have them change their hand over on to the boom.
From time to time I get asked how one should grab the boom: with the palm of the hand facing down (overhand), or facing up (overhand). Let’s start with the easy answer:
Which ever feels most comfortable to you
We can throw heaps of theory at this but as with anything in this sport, whatever feels best to you is correct.
That said there are certain situations where one grip has its advantages over the other. Let’s start with the front hand:
Grabbing the boom with the palms facing down is the most natural position and the one we will instinctively choose. However there is another reason for why we will want to put our hands on to the boom rather than grab it from underneath. The reason is that when we pull the hand towards us we are using our back muscles. On the flip side, if we have and underhand grip we are using our biceps which is considerably weaker than our back.
Also, we manage to have a tighter grip on the boom. This is especially important for situations where there is a surge of power in the sail such as due to gusts, when we are pumping to get planing or when landing a jump.
The underhand grip however does have its applications. For example, having our hand on the boom so that the thumb is pointing forwards allows us to pull the sail closer to the boards tail with much less effort. So, mainly for sailing upwind.
Another circumstance where we might find this grip more comfortable is if the boom is very low. In that case the anatomy of the arm is also better accommodated with an underhand grip.
And lastly, when shifting the sail during the gybe. When we shift the sail we can move the back hand on to the new side of the sail by passing it over the front arm or underneath it. This is usually just a matter of preference. In the case that we pass it underneath, grabbing the boom with and underhand grip will come more natural.
Now let’s talk about the back hand. This one is pretty simple. It simply always hoes in the overhand grip. The position that our body is in with regards to the sail and the movements the back hand has to make will always require it to be facing down on the boom.
That is all regarding underhand and over hand grips. In essence, use the way that feels the most natural and comfortable to you.