[DickR]

For lowering the chain over the winter while making retrieval next year easy, here is what I have done. Get an empty gallon plastic laundry detergent jug (well-rinsed). When you detach the raft at the end of the summer, loop a rope through the handle and a chain link perhaps four feet down from the top end. Leave one end of the rope long, perhaps with a small loop on the end, for use next season in retrieving the rope, jug, and chain.

With the jug empty, it should float the chain completely, but this depends on the chain size and length. The buoyancy of the jug will be 8.3 lb/gallon. Weigh the chain before putting it into service, and figure the weight of the chain of length equal to the water depth. Use a bigger jug or two of them if necessary to provide buoyancy.

By trial and error, let a little water at a time into the jug, to the point where the jug just starts to sink under the weight of the chain. As the chain pulls the jug down, the bottom of the chain will come to rest on the lake bottom, reducing the drag on the jug. You want the amount of water (or air left) in the jug just right so that the jug stops sinking about four feet down. That will let you locate the jug next season easily and retrieve the rope attaching it to the chain with a short pole, while keeping it well below ice and any boat props, even allowing for later drop in lake level before ice-in.

Final thought, on attachment to the raft: don't use rope right at the point of attachment to either chain or raft. Use stainless steel screw-together links (they look like links of a chain, but with a threaded part that lets you open the link for connecting). Rope at a wear point will wear through with the constant motion, even if the point of attachment appears to be smooth. However, one thing you could do is to attach a slightly longer rope as a secondary line between chain and raft. Glance underneath now and then during the summer; if the primary has broken and the raft is held by the secondary, replace the primary pronto.