In Search of Speed and Weatherly Performance
Square Rig
The ideal rig for sail training should include square sails on at least one mast, particularly if operating worldwide on the Trade Routes when the trainees have time to become conversant with its complexities. The exciting downwind performance is normally offset by an inability to go to windward effectively. This can frustrate plans to reach upwind locations and, in the worst case, increases the risk of becoming embayed.
A modern solution is to 'motor-sail' using the engine, making excessive noise, wasting fuel and creating an uncomfortable motion, which puts unnatural stress on the rig. Not an ideal solution!
Fore and Aft rig
The desired weatherly performance can, of course, be achieved with Fore and Aft rigs, which are not so crew intensive but can become threatening downwind in severe conditions. Historically, a compromise has been struck in the Topsail Schooner but it remains only a partial solution to the dilemna.
The Polacre/Xebec rig
Phillip Goode, yacht and sail designer, based in Majorca as the Lloyds agent, had a particular interest in the Barbary coast Xebecs, the most successful corsair vessels of the Mediterranean for two centuries and, arguably, the fastest displacement sailing vessels of all time for their size.
This hybrid sail arrangement of the square Norse sails on the main mast and a massive triangular Lateen on the fore mast in one ship had spawned a cult of swift and weatherly pirate ships whose ability to outrun their pursuers was legendary.
Using the geometry of the Xebec rig, Phillip had designed a number of sail plans for modern yachts which he tested on scale models but - in spite of achieving exceptional results on all points of sailing - they did not appeal to the owners of today's maxi-yachts. Fortuitously he was put in touch with Graham Neilson and a collaborative project was launched for the Pelican.
The model Pelicanina
As a test vehicle, Phillip Goode built a 12.5:1 scale model of Pelican, incorporating the new long poop and his three-masted, 12-sail rig. Her centre of gravity (CG) and meta centre (GM) had to be scaled to that of the future ship and she had to run on her predicted draught marks. Pelicanina was 3.5 metres long and weighed nearly 1/4 of a tonne.
Test results
Pelicanina was sailed in the open sea off Palma. The results, recorded on video, were extraordinary and spectacular. She proved to be perfectly balanced, sailing fast to windward in scale winds of up to 60 knots - unheard of in a square rigger. Her speed off the wind was exceptional and downwind there was no tendency to yaw. It seemed that the secrets of her Arab forebears were being slowly revealed.
Problems identified
As expected, the model identified several technical problems to be solved before this performance could be replicated at full scale:
- Single pole masts were required (à la 'polacre'), the tallest to be 100ft.
- The yards had to brace 18 degrees of the centreline. Normally it is 35 degrees for conventional square riggers.
- To avoid distorting the square sails at these extreme angles, the pivot point of each had to be in perfect alignment - not possible in conventionally stepped masts.
- Suspension points of yards and some stays had to be altered.
Verification of the rig by Lloyds of London
The unconventional sail distribution and rigging plan were bound to raise questions of strength and security, so it was decided to submit all elements to scrutiny under the 'Verification of Rig' procedure now available at Lloyds' Register in London.
Computer Generated Analysis
Here, all sections of the masts, bowsprit and standing rigging were 'modelled' and subjected to the maximum wind speeds acceptable for Full and Plain sail, ultimately reducing to 'bare poles' in hurricane conditions at 122 knots!
From the predicted sail loading and ship movement the mast scantlings were analysed for axial force (vertical thrust), bending and buckling. Rig tensions were then calculated and the standard Safety Factor of 3.5:1 applied to ensure that the chosen wire rigging and terminals would be sufficiently robust. A 16-page report and annexes with colour computer graphics concludes: "...the minimum acceptance criteria were satisfied in all cases".
The masts
The masts are fully galvanised 20-sided steel in hollow section. Historically, 'lower' masts were always stepped on the keel, emerging at the weather deck through mast collars with wedges, packing and aprons to prevent leaking. Now, stump masts - which are integral with the hull and deck structures - are Lloyd's preferred option and are fitted in Pelican. These terminate in a flange, half a metre above the wooden deck. The mast itself, with an identical flange at its base, is then bolted to the stump - ensuring continuity and water tightness.
