I had a hunt around to see if I could find anything, and there's a set of drawings in 'Lifeboat, Design and Development' by Eric C. Fry, if you can get hold of a copy (it's long been out of print, but copies turn up on EBay quite often). I also found a description in 'Britains's Lifeboats, The Story of a Century of Heroic Service ' (Major A.J. Dawson, 1924) :
"At the same time that it adopted Mr. Palmers design, the Institution also, after careful inquiry, took up the invention of his contemporary, Mr. Pellew Plenty, of Newbury, and established boats built to his design at such points as Skegness, Sizewell Gap, Woodbridge Haven, Studland, Portland, St. Mary's, Scilly, and Appledore. Having regard to the extremely modest dimensions of these Pellew Plenty boats - from 17 feet by 6 1/4 feet to 24 feet by 8 feet - the life saving records they achieved we're remarkable, one of them being the means of saving no fewer than sixty-seven lives, and another, fifty one.
Whilst admittedly excellent pulling boats, and popular among Life-boatmen, the craft of Mr. Pellew Plenty's design differed markedly from those of Shields type of boat, being described as approaching the wherry form, and having great fullness in the mid-ship section, with a long,vhollow floor, and upright stem and stern posts.
The dimensions given for these boats were: extreme length, 24 feet; keel, 23 feet; beam, 8 feet; depth, 2 3/4 feet; sheer of gunwale, 14 inches; rake of sternpost, 1 inch in a foot; straight keel and bilge pieces; 5 thwarts, 28 inches apart, 16 inches above deck, and 12 inches below the gunwale strake; pulling 8 double banked oars. Extra buoyancy was obtained for them by means of air-chambers along both sides for and aft, formed by a complete casing or inner boat of a triangular shape, extending down to the deck and coming to a feather edge at the gunwale. They were divided into twelve watertight compartments, each lined with gutta-percha; and their effective extra buoyancy was given at 82 cubic feet, or the equivalent of 2 1/8 tons. No ballast was used; and the internal capacity for holding water up to thwart level was 48 cubic feet, which is the equivalent to 1 1/3 tons. There were six scuppers, each of 2 inches diameter, for freeing these boats of water. In addition, the upper plank on each side was left out, fore and aft, so that, the inner boat being shallow, and of triangular shape, much of the wat shipped would roll out of its own accord when the boat was in motion in a seaway. There was no special provision for self-righting. Layers of cork 4 1/2 inches thick were cemented along the boat's bottom from stem to stern. The rig supplied was one lug-sail. The draught, with 30 men on board, was 16 inches; weight 19 cwt., or, with gear, 24 cwt. these boats were seaworthy and handy, and did excellent service; but the method by which they were expected to free themselves of shipped water left a good deal to be desired."
I'll have a nose about in the Lifeboat archive later, and see if there's anything more in there.
Lance
