I wouldn't prefer the through-hull to be that low, but if mine was, I'd definitely have a proper seacock on it. Then you have a way to shut it off in case of hose failure (and I'd shut it off whenever not aboard as well). I wouldn't see any reason to have the potential exposure to a hose failure sinking the boat when you are not even using the sink. Sure it's not likely, but still. I'd also want a bronze (or chromed bronze) or 316 stainless through hull, but that's just me.
Double clamping is only required on a couple of specific hoses (fuel fills and one other one that I forget at the mo' but I think it's inboard-engine related). Double clamps on any other through hull are optional and fine UNLESS there is not the right amount of space on the barb. Sometimes the barb is not long enough to really accommodate two clamps, and then one of the clamps sort of rides on the edge of the barb and can actually damage the hose or "encourage" the hose to try to come off. So I'd look and if there is not enough room to really accommodate two clamps, then remove one of them. I like AWAB type clamps that are easier on the hose than the ones with all the open slits.
I'd also want to have hose rated for beneath the waterline, although technically you are only beneath the dynamic waterline. But then there's no harm in having the beneath-the-waterline rated hose either. Just a preference.
The one minor plus I see is that you won't have much "droozle space" on the topsides between the through hull and the waterline (for staining, etc.). That wouldn't be enough to encourage me to put it that low, but it is something.
Double clamping is only required on a couple of specific hoses (fuel fills and one other one that I forget at the mo' but I think it's inboard-engine related). Double clamps on any other through hull are optional and fine UNLESS there is not the right amount of space on the barb. Sometimes the barb is not long enough to really accommodate two clamps, and then one of the clamps sort of rides on the edge of the barb and can actually damage the hose or "encourage" the hose to try to come off. So I'd look and if there is not enough room to really accommodate two clamps, then remove one of them. I like AWAB type clamps that are easier on the hose than the ones with all the open slits.
I'd also want to have hose rated for beneath the waterline, although technically you are only beneath the dynamic waterline. But then there's no harm in having the beneath-the-waterline rated hose either. Just a preference.
The one minor plus I see is that you won't have much "droozle space" on the topsides between the through hull and the waterline (for staining, etc.). That wouldn't be enough to encourage me to put it that low, but it is something.