This sketch shows the method of hull skin construction. The copper was a continuous stitch looping in and out of the hull through the wood veneers. On Consuta there are four veneers of mahogany, interleaved with calico (canvas soaked in linseed oil) in order to provide a watertight skin. The hull was stiffened by longitudinal stringers and by a light box type structure linked to the passenger seat, these seats ran the whole length of the hull. This construction gave a very light but very strong hull.
Copper was used because there were no waterproof glues at this time. This form of sewn construction was patented by Saunders and the plywood was called Consuta plywood.
The launch probably weighed just over 3 tons in working order, this is extremely light for a 50 ft boat. The hull has a tunnel stern, reports of the time claim that this helped reduce wash when travelling fast.
Steam machinery was chosen, because this was the only way to achieve high powers reliably. The development of the IC engine during the next few years would of course completely oust the steam engine for this type of application, but for 1898 this was still in the future. We estimate that the steam machinery would have been capable of providing well over 100 HP for short sprints.
These umpiring launches had steering and engine throttle controls in the forward cockpit - this was a needed when closely following the racing eights.
The loco boiler was coal fired and was fired from the back of the boiler. The engine exhausted up the funnel - just as on a steam railway loco. The engine was fitted aft of the boiler and was under an engine housing with a skylight.
The hull construction was so successful that other launches were built using the same copper stitching technique. Saunders had a range of different size launches many of which were propelled by electric. The tunnel stern hull form has also been a great success, similar hulls were made in GRP for umpiring duties just 8 years ago.
When Sam Saunders moved the boat building business to the Isle of Wight, he continued using the patented stitched hull construction for some of the famous petrol engined racing motorboats. This type of hull construction was strong enough to withstand the heavy punishment of displacement hulls running at up to 50 mph. Consuta plywood was also used for many of the amphibius aircraft of the early part of the 20th century.