I have the same problem on my DS II. Same side, but not as extensive. My separation starts about a foot from the bow and runs about 3' aft. The previous owner attempted to repair it with pop rivets, not a very good repair but has held fairly well. I have sailed the boat for several years with the bad repair. It needs to be redone. I was planning a repair with 5200 like Tim did, hopefully this spring.
Some repairs to the hull deck joint are more difficult on a DS II than on a DS I due to the double hull. Some places can't be accessed without the installation of an inspection port. The DS I has a hull/deck joint that can be worked on from the inside, also it is a different type joint with a flat area that originally was stapled together with heavy staples, then had a plastic channel piece added the held on a rub rail. The DS II has a curved hull/deck joint with no rub rail. D&R Marine lists a channel piece that can go over the edge to attach a rub rail to similar to the DS I.
On my boat, the bow eye is also pulling loose. I will be putting an inspection port in the deck in the bow (between the bow and the bulkhead for the flotation tank) to access the bow eye so I can repair it. Hopefully that will happen this weekend, weather permitting. After the repair, since I will have the port, I want to create a line storage area there.
John