Here is the thread where cycle springs put one on a 275. It’s through the stem as you thought would be the best way to do it.
Anyone else see the windlass mod Cycle Springs (Dealer in FL) on a Yamaha 275?
Wonder if the feedback here is the same as it was on FB....



Before you go any farther my suggestion would be to figure out how much all of that equipment weighs and put that much weight in your anchor locker and see how it affects the boat’s attitude whilst on the water compared to not having that weight in there. You might consider having that weight up there and go run it to see how it affects it as well, and maybe even put your normal people load up there too.
Here is what I did with my boat, I installed an anchor roller and quick cleat. If I need a front bow cleat I run the dock lines through the anchor roller and down inside the lock and use the 8” cleat in there.
So, besides the fact the anchor locker hatch opens the wrong way, using the anchor is, well, a bit of a pain. So my friend who has helped me with the other projects came up with an idea and today was the first mock up. The bow cleat is only used really for anchoring, and the 6” pop up cleat is small for my 3/8” rode, so we decided to remove it and make good use of that spot.
Removed bow cleat:
Bow roller with wooden mock up adapter: The final adapter will be made of an aluminum block, but the wooden piece will serve as a good template.
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I replaced the stock raw water wash down hose with a longer one that reaches the bow so I can rinse off the ground tackle as I pull it back in. You could add a thru hull with a sea cock and either make a dedicated raw water wash down with its own pump / plumbing so you don’t have to use your fresh water supply, or put a diverter valve on the existing fresh water pump inlet so you could select from either raw water or your fresh water tank.