Some residents are objecting to a preliminary proposal being explored by the Open Space Committee that would upgrade a boat ramp on state-owned land on the Merrimack River off Church Street. The state Department of Fish and Game has proposed installing a new boat ramp and 120-foot floating dock, nine car parking spaces, 12 trailer parking spaces, and a loading area and handicap space, according to a report posted on the Open Space Committee’s website. Asphalt would be removed and landscaping added, and current green space and trees would be kept in place. Total cost would be roughly $550,000, paid for by the state. But at a meeting earlier this month, abutters presented selectmen with a petition opposing the project, signed by 268 residents. They asked for a conservation easement on the site, and many also expressed concerns about the cost of policing the new ramp, noise, lighting, parking, and its effect on the town’s rural character. Selectman Glenn Kemper suggested creating a subcommittee to explore other sites with river access.