1. A telex to Warren Jones proposing that a number of radical keel shapes be analysed at the Netherlands Aerospace laboratory (NLR) in Amsterdam (by Joop Slooff and his staff): see the attached document

2. Minutes (in Dutch) of a meeting at NLR on 16th April 1981 (well before Ben arrived in the Netherlands) to discuss the details of analysing the performance of alternative keel shapes.

Peter Kiers (from the computer department at NSMB - now MARIN) and I visited the National Aerospace Laboratory in Amsterdam for a meeting with Joop Slooff and his colleague H. Sietsma. Joop and I had been members of a Netherlands Navy Research Group studying future advanced naval vehicles for a year or so and during breaks in these meetings we had discussed the possibilities of improving the performance of sailing yachts in general and the use of their computer codes for this purpose in particular.

I had called Joop a number of times prior to this meeting about the costs and about the computing details of their computer code. Mr. H. Sietsma and Mr. P. Kiers were present because of us needing to know the details concerning the format of the input we needed to provide and the like.

The minutes of this meeting and my personal notes, provide details of what was discussed. The sketches in my personal notes show 3 keel shapes that were specifically discussed. The upside-down keel was one of these. This shape at that point in time was no more than one of a number of possible alternatives, although Joop did explain why this shape was his "favourite".

See the attached document.

3. Telex sent by Ben to Warren Jones about progress made up to 22nd May 1981. Keel III referred to herein is the thicker version of the conventional keel as used on "Australia 1980", drawn by Ben. This keel was later adopted for "Challenge 12".

Darth Vader was Ben's name for the large upside down keel with winglets which Joop Slooff was then analysing by computer. This crude keel concept, drawn up by Joop Slooff and staff, showed potential (a major increase in side force) but its resistance was much too high as the subsequent tests in the tank were to show.

See the attached document.

4. The report written by Joop Slooff on the work he did: see the attached document.

5. Telex sent to Ben on 1st July 1981 informing him of drawing of new aft-body (bustle) and rudder we were preparing so as to shorten the waterline length and increase light-wind performance: see the attached document.

6. Telex sent to Ben on 6th July providing further info on why the waterline length should be shortened: see the attached document.

7. Telex sent by Ben and myself to MARIN on 20th July 1981 from Sydney providing the results of re-fairing the bustle on the hull so as to accommodate the shortened waterline. Ben and I had spent most of the weekend 18-19 July together in Sydney to discuss this and to re-fair part of the hull lines we had prepared: see the attached document.

8. Agenda for meeting with Alan Bond, John Bertrand and Warren Jones at MARIN on 27th July 1981. Ben Lexcen was not present - Joop Slooff and I were: see the attached document.

9 and 10. Letter to Warren Jones dated 5th August 1981 about further work to be done by us, see the attached document, and reply to this letter dated 10th August 1981: see the attached document.

11. Letter to Warren dated 13th August 1981 about the performance improvements, see the attached document.

12. Letter to Ben dated 14th August 1981 enclosing the final drawings of the keel and hull, etc: see the attached document.

13. Letter to Ben enclosing the offsets for the keel and winglets (for the building of the mould for the casting), etc: see the attached document.

14. Letter dated 4th March 1982 enclosing the drawings and offsets for building "Challenge 12": see the attached document.

15. We have all of the original drawings Ben did on the 2 conventional keels (keels II and III) that were tested and all of the original drawings that we prepared for the upside-down keels and winglets (the large version keel IV, and the final version keel V) - these are combined in MARIN report (NSMB) Report No. 44359-1-DR. We have prepared an excerpt of this report, see the attached document.
In the future we might release the entire report.

Back...