17th Century Catamaran Design on the Isle of Wight?

In a biographical sketch of Sir William Petty, in his book Brief Lives, John Aubrey mentions a catamaran boat design that Petty had invented in the early 1660's. In the same paragraph, he also alludes to a similar catamaran design from the Isle of Wight.

Anno Domini 1663 he made his double-bottom'd Vessell,* of which he gave a modell to the Royall Societie made with his owne hands, and it is kept in the Repository at Gresham College. It did doe very good service, but Anno 16... happned to be lost in an extraordinary storme in the Irish sea. (Memorandum: there is yet a double-bottomd Vessell in the Isle of Wight, made by one Mr ... which, they say, sailes well.)^
* Launched about New-yeere's tide.
^ Quaere Captain Lee.
[Brief Lives by John Aubrey]

Details of the maker and design of the Island catamaran are sadly lacking at the moment. However, some idea of its design can be got from Petty's craft.

Petty had designed a twin-hulled boat by fixing two narrow hulls together and rigging it with one huge sail. Launched in Dublin Bay, his first prototype was only one and three quarters tons and was called Invention I. His second catamaran weighed 30 tons and possessed two decks. Each hull was twenty feet long and two feet wide. Described by Petty as a "fantastical bottomless double-bottomed machine", it was launched in October 1662 into Dublin Bay and was named The Invention II.

On 13 July 1663, Pepys wrote that Petty's catamaran "...hath this month won a wager of £50 in sailing between Dublin and Holyhead with the pacquett-boat, the best ship or vessel the King hath here; and he offers to lay with any ship of the world. It is about 30 tons burden, and carries 30 men, with good accommodation (as much more as any ship of her burden), and so any vessel of this figure shall carry more men, with better accommodation by half, than any other ship ... In their coming back from Holyhead they started together, and this vessel came to Dublin by five at night, and the pacquett-boat not before eight the next morning; and when they come they did believe this vessel had been drowned, or at least left behind, not thinking she could have lived in that sea. Strange things are told of this vessel." Petty's second and bigger twin-hulled vessel was named The Experiment by King Charles II, who was present at the launching in December 1664 at Redriffe on the Thames.

1664 Dec. 22
But coming a little too soon, I out again, and tooke boat down to Redriffe; and just in time within two minutes, and saw the new vessel of Sir William Petty's launched, the King and Duke being there. It swims and looks finely, and I believe will do well. The name I think is Twilight [sic], but I do not know certainly.

The Diary of Samuel Pepys.

1664 Dec. 22
I went to the launching of a new ship of two bottomes, invented by Sir Wm. Petty, on which were various opinions ; his Majesty being present gave her the name of the Experiment ; ..."

The Diary of John Evelyn.

The Experiment was sixty feet long, carried sixteen guns, and would seem to have been relatively spacious. On the 13 February 1664/65, Pepys mentioned that "...coming home did go on board Sir W. Petty's "Experiment," which is a brave roomy vessel, and I hope may do well. To test her out, she was raced from Dublin to Holyhead against the three known fastest vessels of comparative size and tonnage - a King's barge, a 'large black pleasure- boat laden with two tons of ballast' and a man-of-war's boat belonging to a Captain Darcy.
At the sign given they all hoisted sail, and they [the crew of the King's barge] got the start of Sir William's and Darcy's boat and kept it by half a score of lengths, until such time as Sir William's was settled in her course and the men had done running up and down, but then she soon passed them by, and come to the ship [used as a mark] near one tenth part of the way before her. . . . We shall now tell your lordship the adventures of the black boat and the barge; these two not being shaped to sail with advantage before the wind, were half a mile behind when Sir William's vessel turned round the ship; and therefore seeing how much she was already on her return, they very unfairly, not going unto the mark, tacked about; and the black boat performed now much better than before. Yet however by the ill play she turned too short, Sir William's now would needs try it with her still; and truly she sculled up and came near the wind, as that by these following misfortunes, she cameth to get before them. Sir William's men, for want of dexterity to shift their sails, stopped twice in the wind, and ran back near a quarter of a mile, in one of which errors, one of her rudders was broken, she also grated twice on the shoal ground, and by reason of the sudden flaws of wind, the sheet of the mainsail did sometimes break loose; and the men wore yet confounded (in this new way) in the names of the ropes."
Comment on the trial: a Report to the Royal Society. (taken from Three Centuries of Sailing by Ernle Bradford, page 26)
John Evelyn, in his diary, gave a good description of Petty's catamaran when he wrote, "Sir William, amongst other inventions, was author of the double-bottom'd ship, which tho' it perish'd , and he was censur'd for rashnesse, being lost in the Bay of Biscay in a storme when, I think, 15 other vessells miscarried. The vessell was flat-bottom'd, of exceeding use to put into shallow ports, and ride over small depths of water. It consisted of 2 distinct keeles crampt together with huge timbers, &c. so as that a violent streame ran betweene ; it bare a monstrous broad saile, and he still persists that it is practicable and of exceeding use ; and he has often told me he would adventure himselfe in such another, could he procure sailors, and his Majestys permission to make a second Experiment, which name the King gave it at the launching" [1675 March 22].

A reference to Petty's catamaran is found in a poem called "Verse Said to be Written on the Union" by Jonathon Swift, in which he writes: "...our vessel with a double Keel/ ... The Pilot knew not how to guide./So tossing Faction will o’erwhelm/Our crazy double-bottom’d Realm." Here there is the suggestion that steering the catamaran was difficult and was an acquired skill. Indeed the vessel had two rudders and in the race from Dublin to Holyhead in 1665, it is significant that it was one of the rudders that broke.

From a report by a committee set up by the Royal Society to examine The Experiment, it is clear that Petty's catamaran sailed much closer into the wind than conventional ships without making too much leeway. The report outlined the main concerns about the vessel thus:

"...The chief objections were these which follow: 1st: The danger of divulsion and separation of the two cylinders, by the irruition of the water; for as much as the same is received by two heads, which stand diverging as in the wind end of a tunnel. 2nd: The falling in of the water between the two heads obliquely. 3rd: The danger of being over run, and submerged by a head sea, the vessel sailing swiftly against it, especially when her stern is raised, and consequently the head depressed in a wave. 4th: The danger of her platform being blown up, either with the rising of the sea between the cylinders, or rather by the seas coming in by her broad windward side, and cuffing her under the platform."
[History of the Royal Society by ]
However, in the same report, a Mr Southwall, who sailed in The Experiment, refuted these and reported "...that, for strength of the cylinders, her contexture, he never did perceive the first tendency for a divulsion of the cylinders, but that, on the contrary, the waves that rose up big and strong, fell mostly on them, for their rounded shapes made all the force slide away on each side ... As for sailing against the wind, she does it extremely well, she stops well at a tack; she makes way as she looks without sliding down the wind; and come within less than five points of the compass, some say very much less." One of the advantages of Petty's catamaran was its ability to sail closer into the wind than conventional ships - a quality that was vitally important in cutting down on the distance of voyages.

It would seem that, although Petty conceived the idea of a catamaran and designed it, he had also found some backers to provide finance for the venture and these men thereby became his co-partners:

1664/65 Feb. 18
Up, and to the office, where sat all the morning; at noon to the 'Change, and thence to the Royall Oake taverne in Lumbard Streete, where Sir William Petty and the owners of the double-bottomed boat (the Experiment) did entertain my Lord Brunkard, Sir R. Murrey, myself, and others, with marrow bones and a chine of beefe of the victuals they have made for this ship; and excellent company and good discourse: but, above all, I do value Sir William Petty.

The Diary of Samuel Pepys.
In December 1684, just three years before his death, he built an even larger version, St Michael the Archangel. However, this one was a complete failure and Petty's hopes for catamarans disappeared. There was no more interest shown in the catamaran design until about two centuries later. Petty's idea was way ahead of its time but the question remains whether Petty derived his idea for his craft from the "double-bottomd Vessell" made on the Isle of Wight, mentioned by Aubrey. The Island maker remains anonymous, mentioned only as Mr. .... but known to a Captain Lee. If only ...?


The Diary of Samuel Pepys.
The Diary of John Evelyn.
Bodleian MS Lyell Empt. 32: Correspondence and papers concerning Petty's `double bottom' boat experiments and shipping generally, 1661-1684.
National Maritime Museum SPB/16 (MS 8053): documents relating to Sir William Petty's proposal for a double bottomed ship, 1662-1685.
Sir William Petty. Portrait of a Genius, E. Strauss. (The Bodley Head.1954)
Three Centuries of Sailing, Ernle Bradford