The lift at Portsmouth Historic Dockyard saw the load cell attached to the Vaughan, which had a 5t auxiliary, via twin 10t 2m strops in basket formation through a 30t-plus shackle on the load cell.
The load cell was then connected to each vessel via a 30t-plus shackle linked to a double chain spreader to two 15m 10t strops in basket formation around the boat.
One of the boats, the Green Parrot was a 45ft picket boat used by the queen as her royal barge during visits to Portsmouth, while the second was an ST-1502 seaplane tender used in World War II.
Accurate weighing was also required because the Green Parrot is having new engines and propellors fitted.
A handheld remote was used with the 25t Radiolink Plus for wireless operation at a safe distance. The Green Parrot was the heavier boat at 16t due to the weight of the royal accommodation.
"We’re delighted to have played a part in the country’s naval history by helping to find the exact weight of these two historic boats," said Straightpoint director David Ayling.