Stretching MkI to MkIII

1. The new centre section raft being constructed for The Princess Anne at BHC	2. The Princess Anne at BHC's East Cowes works being prepared for separation	3. Another view of engineers separating the craft in to two pieces	4. The rear of the craft being stripped for it's conversion work
5. A view of the rear half of the craft (looking aft) stripped down to accept the new centre section	6. The craft cut in two with the new raft being positioned	7. The longitudinal bulkheads are positioned on the raft	8. Work continues on modifying the Mk I front and rear to take the new centre section
9. Work on The Princess Anne continues as the new centre section for The Princess Margaret is built alongside	10. Nearing the completion of major structural work	11. The rear of the craft, now having had the engines re-fitted	12. After conversion work The Princess Anne is readied for sliding out of the workshop on the rails seen in the foreground
13. A closer view of the rear of the craft in the workshop	14. The huge craft is slid out on to the East Cowes pad to await the fitting of the skirt	15. A different view from slightly above shows the longer craft emerging	16. Another view of the craft from the front quarter as work progresses
17. Work to fit the skirt sections, propeller pylons & fins gets underway	18. Skirt sections being fitted to the craft	19. Now with some skirt fitted and one of the propeller pylons	20. The Princess Anne being completed in preparation for hovering trials
21. An aerial view taken on the same day as the previous picture shows the limited space available at Cowes	22. After fitting the skirt system on The Princess Anne is tested on the pad before trials begin in the Solent	23. The Mk III craft takes to the water for the first time, ready for trials and ultimately re-delivery to Seaspeed

1. An early artist's impression of a Mk III craft in Seaspeed livery	2. An artist's impression of The Princess Anne after stretching to Mk III status	3. The concept showing the new centre section to be inserted in to the Mk I craft	4. The centre section in position, and then inserted to make the Mk III craft
5. Testing a 1:12 scale dynamic model undergoing tests in waves on BHC No. 3 towing tank	6. Another picture of the same model which is now in the Hovercraft Museum collection - though having been cut in to 4 pieces by BHC due to its size, it is in need of restoration !	7. MPs visiting BHC on 7 July 1975 view testing of the Mk III model	8. The model being towed along the tank in tests
9. Adjustments are made by an engineer - showing to advantage the size of this model	10. Mk III dynamic model undergoing remote controlled free-flight tests to assess handling characteristics

1. The Princess Margaret was stretched slightly differently, the centre section having been pre-fabricated	2. A closer view of the new centre section	3. Nearly in position between the separated sections of the Mk I craft	4. The two halves of the Mk I being joined to the new centre section
5. Widening the superstructure of the craft required extensions to the roof beams and panelling	6. This view shows the openings in the roof to allow the Rolls Royce Proteus engines to be installed and removed	7. Final installations being made before roll-out on to the pad	8. Completing the structural work
9. New skirt sections suspended in the skirt workshops are readied for attachment to a MK III craft