While you approach will deliver a litttle water under better pressure, another solution is to deliver a LOT of water with less pressure.
For about $60 total I got:
- a 2,000 GPH bilge pump on eBay (took a while to get a big one cheap),
- fashioned a hook-dipper out of $5 worth of PVC
- about 15 feet of 14 AWG marine wire, butt-connected to the pump leads with a cigarette plug end
- 1 simple Radio Shack in-line switch
- 15 feet of 1.5" hardware store sump pump hose
The PCV hooks around a stanchion and dips the pump overboard. Plug it in, flip the switch and LOTS of water, albeit without a lot of pressure; no hose nozzle because one should not shut-off a bilge pump's flow. But for cleaning dirty anchor chain and line, I've found more water with less pressure to be superior to less-water with more pressure. Those washdown pumps are rated at 4+/- GPM, maybe 250 GPH. This used bilge pump is rated at 2,000 GPH... and it does flush off the crud.
That is was way less money and way easier to build-install was only a secondary benefit.
Picture here: http://plasticclassicforum.com/forum...php?f=4&t=5901