These three yachts are all basically the same design with different tops and lay-out changes.
The She 31, or She 31b as most are, is the original. She is low and pretty and fast. Unfortunately she does not have much space below decks and the forecabin, in particular is very cramped.
To overcome some of her shortcomings South Hants Engineering produced the 9.5 Traveller which had a higher, longer coachroof, two inches more headroom (from 5ft 10in to 6ft) and improved accommodation.
After SHE ceased trading around 1979, the moulds were taken on by Laird Adams Engineering. They returned to the original deck moulding for the Delta 94 but added several inches to the topsides which extended her overall length and also created 6ft headroom. The accommodation was better than either SHEs.
The weight of the boats increased with each model but so did the sail area. The Delta is probably the quickest of the trio and the Traveller the slowest.