that trolley looks well over-engineered for a job a sailing dinghy trolley (eg for a Finn) should cope with, at vastly less cost.
The Uffa Fox weighed 1700lb according to Wikipedia (yes, I know), the Finn weighs about 250 ? No weights given for the Saunders-Roe. If you dropped a 250lb dinghy from an aeroplane would there be anything left apart from floating wreckage ?