I have had my 170 for 3 summers so far. I recently had some work done which elininated the cup holders. Before, the boat was extremely tender. Although due to weather (too hot, no wind, too rainy) and other obligations (guests) I have not sailed a lot since the new work, the boat seems less tender. (I also had my centerboard replaced with a newer weighted one). Since the boat is docked for the summer, there is no way to tell if there is water in the hull, until the fall when I take it out. I had noticed in previous autumns and at other outhaulings that the boat had taken on a great deal of water, I now believe, because the cup holders leaked RAINWATER badly. I think that that added movable "ballast" helped my 170 be more tender (upon heeling, the weight --water-- moved where I did not want weight --the low side). So if you have a 170 with those (stupid) cup holders, remove them and plug up the four holes. That's my advice. The adhesive that Hunter used is not a permanent bond between the cup holders and the hull, which will lead to water in your hull. Also, the pipe connection at the bottom of the cup holder and/or to the hull is not permanent either. Fair sailing, and no knockdowns!