Olin Stevens is reputed to have invented the dorade box ventilator shortly after DORADE (his design), was launched. Cowl vents used to pipe directly below which at sea can be a wet problem. If you have ever spent time below in a stuffy cabin going to windward with a sea running - and you've been in the same conditions below in a boat with ample dorade box ventilators - you know dorade boxes, can't be beat. They also keep a cabin well ventilated in a rain storm at anchor. And for a moored boat, there's no better way to ventilate and keep it dry, below decks. I built 2 replacement boxes for the originals on my boat. The dovetails crafted originally (the old boxes to the right) were beautiful. But I'm not so sure dovetails are the best joint for pieces like this. And they are time consuming. Plus there were a pair of added blocks to mine for tying down a dinghy and another for storing a danforth anchor. They are shot. I kept the new ones, simple: Plain butt joints, epoxy, SS screws-plugs. Easy. Material is an affordable tropical hardwood I can get locally($8.00/ bd. ft.) This stuff, after staining and varnishing, looks great. To improve them, I used 1/2" thick Polycarbonate for the tops, for two reasons. The standpipes inside that supply air to the cabin, will also act as dead lights. We'll get extra sunlight in the head, and passageway between the saloon and forward cabin. Both those areas could use the extra light. Plus the top or horizontal surface of anything on deck - that is bright wood, is the hardest to maintain because of UV damage. This will make the boxes much easier to care for. Today was another rainy day on the coast of Maine; I put it to good use cutting and fitting the Lexan tops... The Lexan front edges were cut to 20 degrees to match the boxes. Once a good fit on the front was had, the Lexan was cut 1/8" oversized, to overhang the other 3 edges. Then: Clamp oversized piece precisely, and drill holes for screws + countersink. Fasten Lexan (dry), to boxes. Once secured to box, trim the 1/8" off the 3 overhanging edges with a router and bottom roller trim bit. Finish: Add a slight round over profile to the crisp edge (won't easily snag lines), hand shape the 20 degree. Done. Now they're disassembled, for easy finishing. Once finished, the tops will be - bedded/ secured. I previously fine tuned the fit on the boat - check. Here's a close up. I picked up the 1/2" Lexan from the local glass store (scraps, good deal). The nickel plating is wearing off the 56 year old cowls and trim rings. I'll buff them up a little but by the time Xmas has a new owner, the cowls will probably be all green. And the dog is pointing out the obvious: I need to spray the throats red, again.