Casting a spell vs. firing a bow in bad conditions

[Zag24]

I'm playing a spell-caster and we're on a ship in a really terrible storm, when (of course) some huge tentacles appear coming up over the side. I tried to cast a spell, and my GM said that I needed to make a concentration check at DC 21, which my first level character would need to be pretty lucky to get off. I'm ok with this, though it is the first game I've been in where they actually bother with concentration checks.

The the archer shoots the thing with his bow. Ummm, what? Mumbling a few words and making gestures with one hand while I'm holding on to the mast with my other arm seems a lot easier (on the badly rolling deck) than using both hands to nock an arrow, draw a bow, and release with anything like aim.

So, is there an equivalent of concentration for using a bow?

[SunsetPsychosis]

This wouldn't happen to be the Neither Man Nor Beast game on RPOL, would it? And the rules specifically state that concentration checks are required for heavy weather. As for concentration check equivalents for a bow, no, but there are attack roll penalties. They could fire the thing, but without excellent rolls there wouldn't be much in the way of accuracy.

[Abraham spalding]

Weather wrote:

The combined effects of precipitation (or dust) and wind that accompany all storms reduce visibility ranges by three-quarters, imposing a –8 penalty on Perception checks. Storms make ranged weapon attacks impossible, except for those using siege weapons, which have a –4 penalty on attack rolls. They automatically extinguish candles, torches, and similar unprotected flames. They cause protected flames, such as those of lanterns, to dance wildly and have a 50% chance to extinguish these lights. See Table: Wind Effects for possible consequences to creatures caught outside without shelter during such a storm. Storms are divided into the following three types.

The more you know...