A “double-bottomed” ship, a kind of catamaran, designed by Sir William Petty. Here’s a quote from this review of Ted McCormick’s William Petty and the Ambitions of Political Arithmetic by Steven Shapin:

The ship was an experiment in science, technology and entrepreneurship. No one had ever seen such a vessel; it violated the conventions of the shipwright’s art; and among the knowledgeable it was generally an object of ridicule and opposition. There was, Petty acknowledged, ‘scarce a good word for it’ from anyone in the business. Most experts thought it wouldn’t work, and some worried that, in the unlikely event it did, it would be a technology too far. Samuel Pepys, the Navy Board’s clerk of the acts, was a supporter, while the master shipwright Anthony Deane said Petty’s design ‘must needs prove a folly’. The navy commissioner Peter Pett told Pepys that the double-hulled ship was ‘the most dangerous thing in the world’: if it was successful, the secret would get out, and it would be the ruin of English trade and sea power. The Dutch, with whom England was about to fight the second instalment of a series of naval wars, might use the shallow-draught ship to sail right up the Thames and lay London waste.

Here’s a photo of a model of a similar multi-hulled ship of the period.

25 Mar 2005, 3:47 a.m. - vicenzo

The Navy used the name:The Navy had one ship, 32 guns 5th rate Chatham May, 1679: another in 24 6th rate 1740 The Experiment (or Experimtt.) departed Barbados for London, England

30 Mar 2005, 3:39 a.m. - vicenzo

The Experiment is "wot" it means, a ship with a double hull. 22 dec 1664 by John Evelyn "...I went to the Launching of a new ship of two bottomes, invented by Sir William Petty by a modell of Sir William Petty on which were various opinions: his Majestie present, gave the name Experiment: ..." No more removing a plank to let the water out or in.

30 Mar 2005, 3:45 a.m. - vicenzo

Date confusion by JE or use of a temporary name for a non standard ship. curious?

30 Mar 2005, 3:50 a.m. - vicenzo

Found An answer: at Sir Wm Petty: {mention in Diary] "...At various times between 1662 and 1684 he designed four twin-hulled ships which were built and tested with varying success. His accounts of this were edited by the Marquess of Lansdowne and published in 1931..."

24 Jan 2006, 8:48 a.m. - Pedro

The Experiment. “Charles had dicoursed for hours to Sir William Petty on the philosophy of shipping. In September 1662 the King launched a new type of ship with 2 bottoms, invented by Petty, which he aptly christened the Experiment. Later the King would tease Petty about his boat’s odd appearance. In vain Petty offered to lay odds for his ship against “the King’s best boats”: Charles refused to lay the bet and continued the teasing. Yet Petty, undiscouraged, built other double-bottomed boats, and made further experiments in naval design." (Antonia Fraser…King Charles II)

24 Jan 2006, 7:23 p.m. - in Aqua Scripto

"...Early Sir G. Carteret, both Sir Williams and I on board the Experiment, to dispatch her away, she being to carry things to the Madeiras with the East Indy fleet..." Does this fit the other above information?

23 Dec 2007, 3:27 p.m. - JWB

17th Century Catamaran

20 Aug 2010, 7:44 a.m. - Douglas Lane

Not a catamaran - that is called a multi hull. The Experiment was one hull inside the other - a double hull, with the hope that it would be harder to sink.

4 Feb 2011, 7:33 p.m. - cum salis grano

additional info, thanks to Terry Foreman

2 Nov 2016, 3:26 a.m. - Terry Foreman

An image of a model of Petty's twin-hulled ship : the Royal Society's picture gallery


Chart showing the number of references in each month of the diary’s entries.