Number 7 Boathouse (Building Number 1/29)

No 7 Boathouse, also known as Building Number 1/29, is a structure from 1875, originally serving as a mast house before becoming a boathouse. It was built on the site of an earlier boathouse. The building features a timber frame with weather-board cladding, while the northeast section is constructed of red brick with some blue headers in English bond. The roof is hipped and covered with corrugated iron.

The exterior consists of four parallel ranges, each one storey high, with a total of 18 bays arranged in a 2:2:2:2 pattern, extending over Mast Pond. It has small-pane wooden windows set in projecting wood frames and board doors. The structure is supported by a wood and iron substructure, featuring iron posts with wooden braces supporting iron girders and wooden joists.

On the southwest elevation, there are eight continuous wide entrances fitted with folding doors. The rear has a double board door leading to the weatherboarded left-hand section. The right-hand section, made of brick, includes three recessed bays flanked by pilasters on each side of the central bay, which has stepped, cogged heads and a central round-arched entrance that is now bricked up, complete with brick imposts and keystones. The left return features a brick section with tall recesses and cogged eaves, along with replacement windows beneath gauged bright-red brick flat arches. The right return has a bracketed iron balcony and 18 windows.

Inside, the building has square timber posts with braces supporting longitudinal and cross-beams. The wooden roof trusses are fitted with iron king pins and a plank ridge-piece, and there are skylights in the northern pitches of the roofs.

This boathouse is one of a pair, alongside No 5 Boathouse, and along with the Lower Boat House in Chatham, represents the last surviving examples of a once-common type used for constructing and storing small boats.