I _think_ there should be enough space in the locker to install such a partial bulkhead. But remember that the locker hatch is not that big. So I imagine it will be a pain to both install the bulkhead and to put the first 20 m there each time you have used
them. That said it might still be a feasible idea.
There are also other possible technical solutions that might or might not work like:
So far I didn't try either of it.
Using 8mm chain would probably eliminate the problem alltogether but it comes with a big caveat:
As I pointed out earlier, with the smaller chain you also loose a lot of weight. While this is a desirable effect for the boat trim (more for light deplacement boats than for an Amel), it is abolutely undesirable when the chain is NOT in the locker but in the
10m of 10mm chain weigh about 23 kg while 10m of 8mm chain weigh only 13kg. For an anchor chain weight equals to damping. A lighter chain will come stiff like a rod much earlier than a heavier chain when swell and wind increases. As soon as the chain is solid
stiff the damping and force absorption cease to exist and the full force of wind gusts and swell will take effect on your anchor thus increasing the danger for it to break out considerably.
This not so much a problem in light conditions, but in heavy weather it can make a big difference.
I consired switching to a 8mm Chrome Duplex chain myself but gave up on that thought when I realized the consequences.
Michael, SY Sioned, Maramu #148