By having one hole lower on one side than the other, almost all of any water that collects in the chain locker will drain out of that one side. Because of this any solid matter, sand, mud, seaweed etc., that you have pulled up with your anchor chain and which you didn’t wash off before it went into your chain locker, will tend to collect on one side next to that lower hole, thereby leaving the upper hole clear to handle those occasions when your boat buries it’s bow into a solid wall of water. If both holes were at the same level, any build up of solid matter within the chain locker would likely block both holes at more or less the same time, thereby allowing your chain locker to fill with water before you had noticed there was a build up that would alter the vessels trim, forcing the bow lower in the water, and which in consequence might endanger your safety.
Sitting in the marina on our 2001 34 with its unequal height drain holes looking at a new 40 ... with unequal height drain holes and really can’t think of a reason.
Illogical Germans? Surely not 
Any idea why?
Illogical, most definitely not !
