The South Shore Yacht Club, located on the Back River and accessed from the Abigail Adams Park off Route 3A.
The Back River is navigable up to the Fish Ladder in Jackson Square in Weymouth but is not very deep with broad mud flats.
The old Hingham Shipyard, now a ferry terminal, with a small shopping, movie theater, restaurant area and Marina, is southeast on the other side of Stodders Neck.
Update: Kayak rental: one of the retail stores in The Shipyard retail area is a EMS (Eastern Mountain Sports). They rent and sell kayaks and paddleboards. Classes on both are also available.
The Wessagusset Beach area in Weymouth contains several locations where parking and close proximity to the water go together. Abigail Adams Park is a relatively new park with free parking and near two small stony beaches on the Back River. The only trouble with this area is that at dead low tide we’re talking real, real shallow. I’ll try to update with a photo of low tide conditions.
Also in this area, Webb Park with a longer walk to the water, but closer to Hingham Bay. The waters edge there is sand and stone.
The Town Beach and Boat Ramp is between the two but requires a town beach parking sticker. Also there was a grumpy old man there to collect the launching fees for the boat ramp who, if he’s still there, will try to con kayaker’s that they must pay to launch there.
Update July 2012
When I was a kid, I always wanted to spend the summer sailing boats. My father decided I should play baseball. He grown up in the Working Boys Home and the highlight of his experience there was being taught baseball by the priest that taught Babe Ruth. It turned out that he exactly fit Babe’s old uniform and he got to wear it in games. (He couldn’t keep it otherwise the family fortunes would be better shape). At any rate I had to play baseball, which is why I learned to hate baseball.
As I said I wish I could have gone sailing.