The New Brig: Get Clued Up!
The STAs Stavros S Niarchos has been undergoing sea trials over the last few weeks. Here Michael Willoughby, who was closely involved with the development of the new vessel, takes an in-depth look at her design, and the philosophy behind it .
In 1997 the Sail Training Association came to the decision that replacement vessels were needed for the two ageing schooners, Sir Winston Churchill (1996) and Malcolm Miller (1967). Both vessels had given wonderful service in providing young trainees with a disciplined and challenging experience that can only be achieved on board a vessel under sail.
It was decided that the replacements should be square-rigged and various proposals were examined, and it was during this period that the STA were sent details of two unfinished auxiliary sailing ship hulls that were lying in Lubeck. The design was by Aberking and Rassumssen for West Indian cruise ships, but while under construction work on them had been halted and the hulls put up for sale.
Mr Pritchard-Gordon of the STA, with two naval architects, went over to Germany to inspect them as possible sail training vessels. Their inspection proved positive so a decision was taken to purchase them, and a contract transferring them to the STA was signed in the autumn of 1997, and shortly after, the two hulls were towed from Lubeck to the River Wear.
The only construction drawings available were the lines of the hulls which were passed to Burness, Corlett & Partners and myself. We were asked to produce a basic design for their completion as sail training vessels and to draw up a tender document. This was completed in early 1999 and sent out to eight prospective shipbuilders.
The initial specification for the two hulls was for them to be barque-rigged, and the proposal called for a raised forecastle head and extended bow which increased the water line length to 41m on a beam of 9.91m and draft of 3.5m. The beam required the lower yards to be 19.8m long with the spacing between the fore and main masts about 18m, but by reducing the yard lengths to a minimum of 18.8m and the masts spacing to 15.5m, there was just sufficient space to step a mizzen mast 8m abaft the main mast. This arrangement created a number of problems, the most significant being that the yard arms would be too close to each other when braced in opposite tacks. Eventually it became apparent that the barque design was impractical, and after four months trying to resolve the problems, a new design was set out with the vessel rigged as a brig. The result was a design that looked right, obeyed the rules for brig designs of the past, and in service will, I believe, prove to be right.
We had the good fortune to be responsible to the chairman of the STA Building Committee for the design of a practical square-rigged training vessel. A proposal was put forward with reasons for the change from a barque to a brig, and it was agreed that the two vessels should be so rigged.
The design of the rig was standard, except that instead of the depth of the fore course and mainsail being half the head they have been reduced by 3,000mm to make them easier for the trainee crews to handle. This has the additional benefit of reducing the height of the two masts.
The original hull had 900mm bulwarks on the main deck without pin rails and a 600mm one on the poop. Our proposal called for a main deck bulwark of 1,300mm with pin rails and a 1,000mm bulwark on the poop with pin rails, but with no topgallant rail. This arrangement gave the vessel a continuous sheer line from stem to stern.
The proposal was for a steel spike bowsprit with a 14-degree steeve to carry the four head sails. The lower and topmasts to be single steel spars with timber topgallant and royal masts and 1.5m poles to carry the statutary lights and aerials, with timber spars for the spanker.
Each mast to carry three lower yards of steel and two upper yards of timber, with the main mast having three staysails and the spanker. The 10 square sails and eight fore and aft sails making a total sail area of about 1,000sq m.
The foremast would be 35m from the water line to the top of the pole and the main mast 36m, but in all other respects the two masts would be similar. The two lower yards to be 18.8m between the yard arm bands, with the royal yards half their length.
The standing rigging to be to commercial sailing vessel standard made up with plough steel wire with turned up ends secured with four seizings with no splices or pressed-on fittings. The finished shrouds and stays, except for those carrying staysails, to be protected by being wormed, parcelled and served their full length with leather round the mast loops.
When the yards are braced round there is a considerable turning moment on the mast, and with the shrouds and backstays looped around the mast, it is free to turn on its axis over its whole length, the stress being confined to the heel only. This obviates the local stresses created by welded lugs on the masts for shrouds and backstay, which prevent them turning, with possible mast failure as happened on the full rigger Christian Radich.
The main machinery for the vessels, including the two 390kw Mercedes auxiliary engines were part of the purchase contract but the engine room space was bare. We were therefore required to include in the design proposals the installation of all the machinery, electrical system, air-conditioning and pipe work throughout the vessel to meet the STA requirements, including the twin-screw propulsion units and bridge controls.
The authorities required a power steering gear with a mechanical emergency system. It was explained that the failure of a power system could very easily result in the dismasting of the vessels, so it was agreed that mechanical steering should be main system, with power system as the emergency steering arrangement.
Design drawings were drawn up to meet the STA specifications for the accommodation to be air-conditioned, with facilities for 48 trainees, four petty officers and 12 after-guard, with the domestic arrangements, with machinery space, pumping systems and tanks, dry stores, refrigeration and frozen compartments on the lower deck, sufficient for the vessel to make 28-day sea passages.
The original hulls were built to Germanischer Lloyd Rules and it was agreed that the vessels should be completed under their survey. For my part, this had a considerable advantage as they had supervised the building and maintenance of large fleets of commercial square-rigged sailing vessels for over a century, and more recently have continued to do so for the German sail training vessels.
There were four tenderers for the design contract, and the joint BCP and Michael Willoughby one proved to be successful. A contract was signed in March 1998 by the STA, after which it took six weeks for the building tender to be drawn up and approved.
Tenders were sent out to eight European shipbuilders for the completion of the hulls as sail training vessels to our joint design. Appledore Shipbuilders were the successful bidders, and in late 1998 a building contract was placed with them for delivery of the first vessel in November 1999.
The Appledore design office then produced the building drawing, and in February 1999 the two hulls, loaded with their machinery in packing cases, were towed from the River Wear and berthed in the shipyards covered building dock. After their arrival the design contract with Burness, Corlett & Partners was suspended, leaving me to complete the design of the rig, weather deck and hull modifications in collaboration with the shipyard design office and the contract riggers, T Nielsen & Company of Gloucester.
The project team responsible for completing the first vessel was Mr Pritchard-Gordon for the STA, who had overall responsibility for the contract, Mr Geoff Dean, the Managing Director of Appledore Shipbuilders, and Mr Tommi Nielsen of T Nielsen & Company, who was sub-contracted by the shipyard for making the two masts and the 13 spars, and for rigging the vessel ready for sea, complete with sails made by James Lawrence & Company of Brightlingsea.
The first task of the shipyard was to remove the large steel structures above the main deck before building on a new raised forecastle head, fiddle bow and forefoot. The additional weight aloft and the sailing loads required an additional 50 tons of permanent ballast to meet Germanischer Lloyd sailing ship stability rules. The shipyard therefore increased the depth of the box keel to take this, which resulted in the draft being increased to 4.6m. This increased draft should greatly improve the windward performance of the vessel. The bulwarks have now been raised to 1.3m and provided with timber pin rails on the main deck and 1,000mm bulwarks on the poop with pin rails.
The forecastle head is connected to the mid-ship deckhouse by a narrow bridge with an emergency generator, workshop and storeroom below. The deckhouse on the main deck houses the galley, pantry and a three-table mess room for trainees, two heads, two air conditioning units and a ships office.
A new deckhouse has been built on the poop consisting of a raised chartroom and bridge, the Masters cabin and Officers ward room. On the tween deck there is accommodation for four POs forward with their mess room, mens and womens shower rooms and six eight-berth cabins for trainees. Under the poop there are two main shower rooms with two small ones for ladies, and aft of them there is accommodation for the 12 permanent crew, making a total complement of 64. On the lower deck there are the fuel and fresh water tanks, dry store rooms, refrigerated and freezer rooms and the main machinery space in the stern.
The hull is divided into watertight compartments to meet the damage stability rules set out by the authorities. To maintain their integrity on the accommodation deck, there are single lever, quick action locks on the watertight doors that can be instantly shut in the event of an emergency.
The vessel has been rigged as a powerful well balanced brig, carrying 18 sails totalling 1,162sq m, made up of four head sails, 10 square sails, three main staysails and spanker. The 10 lower sails are of heavyweight Duradon canvas and the eight upper sails of lightweight Duradon canvas. The running rigging and layout of the pin rails are to the normal practice for square-rigged vessels, set out to reduce chaffe to a minimum.
The bowsprit is a steel spar 14m long and 11m outboard, from bed to the royal stay band. It is 500mm diameter at the bed and 200mm at the royal stay band with a 300mm-long wood plug in the end. The steeve is 14 degrees and the outboard end 5.3m above the sea. The bobstays are round steel bar, the outer one to the topgallant stay band is 40mm diameter and the inner one to the inner jib stay band 65mm diameter. The six bowsprit shrouds are galvanised chain, the outer pair leading from the topgallant stay band, and double ones from the inner jib stay band. A safety net is fitted from the fiddle head to the outboard end.
On the fore end of the forecastle head there is a short pin rail for the four downhauls of the headsails. There is the windlass with an access hatch to the chain locker, and on the after end there are eye bolts for the eight standing parts of the headsail sheets with hardwood fair leads at the break for leading the hauling parts on the main rail.
The main mast is one metre higher than the fore mast but in all the other respects the two masts are similar. The lower masts and top mast are single steel spars, the fore mast 27.5m from heel to topmast cap, and the main mast 28.5m, both have a diameter of 530mm at the partners, and 260mm at the top mast cap. The timber topgallant masts are each 9.3m long from heel to royal stops with 2.5m doubling, and both masts have 1.5m poles for navigation lights, aerials and instruments. Because of the equipment on the pole masts, small angled signal yards are fitted to both masts at the royal stops for flying the house flag, courtesy flag and signals. When the foremast was stepped an old tradition was maintained when a 1903 golden sovereign was placed under the heel.
All six lower yards are steel spars, the lower ones are 18.8m long and 30mm diameter at the slings, the lower topsail yards 16m long and 320mm at the slings, and the upper topsail yards 13.35m long and 280mm at the slings. All the steel yards are fitted with long timber plugs to take the outer end of the flemish horses.
The four upper yards are timber, the topgallants 10.4m long and 190mm diameter at the slings, and the royals 9.6m long and 150mm diameter at the slings. The two lower yards are on trusses with chain slings, and the lower topsail yards on cranes and are fixed. The three upper yards are on halliards, the steel upper topsail yards are on mast tracks on the fore side of the topmasts, and the timber topgallant and royal yards on parrels.
All the yards are fitted with a jackstay 40 degrees forward of the centre line for bending on the sails, with a safety jackstay on top of the yard. There is also provision for a wire safety wire to be fitted along the yard for trainees to clip on their harnesses when working out on a yard.
Fore and Aft Sails
The bowsprit carries four head sails on their respective stays and each is rigged with halliard and purchase, sheets and downhaul, with fixed length tacks.
The mainmast carries three staysails on the three upper main stays with the spanker on the gaff and boom. The spanker boom is fitted with twin sheets port and starboard, leading to bitts on the bridge deck so that it can be controlled on either tack. The gaff has two vangs leading to the poop rail port and starboard. The sail has four brails per side and is furled along the gaff with the clew inhaul whip to the mast.
Shell Plating and Steel Work
As built, the scantlings of the hull were designed for the low-powered cruise ship, so modifications were needed to take the heavier loads imposed by a full-rigged sailing ship. The sheer strake was therefore strengthened, also the deck beams in way of the standing rigging of the masts. The tank tops also required strengthening to take the vertical static and sailing loads of both masts.
The brigs are powerful sailing vessels with a multiple of fore and aft sails to achieve a good balance in all weather conditions, which in combination with the fine lines of the hulls, will ensure a good all-round performance. As training vessels for short term trainees it is an excellent rig, it is not too heavy, and unlike the schooners which can be worked from the deck, they will require their trainees to work aloft, whatever the weather, from the moment of the vessels put to sea until they return to harbour.
Like all square-rigged vessels, the brigs will only sail when under both square sails and fore and aft sails. The fore and aft sails alone have insufficient power to take the vessels to windward, and although they will point closer to the wind, they will make excessive leeway.
The braces have been marked for the yards to be braced to 40 degrees, giving a closehauled performance of about 70 degrees off the true wind, but if necessary they could be braced a further five degrees in an emergency.
With the yards braced to 40 degrees, and the angle of attack of 15 degrees, and leeway of 10 degrees, the course made good will be about 65 degrees off the apparent wind, but a further five degrees off the true wind, so will actually make about 20 degrees to windward.
With their broad beam relative to the water-line lengths, the brigs will be very comfortable and seaworthy vessels, but they will also create a comparatively strong lee bow effect when going to windward which, combined with the windage from the deckhouse and bridge on the poop, will impose a considerable turning moment about the foremast. Watch officers will therefore need to pay great attention to the steering to avoid the vessel being taken aback in a sudden increase of wind strength.
When squalls are expected the vessels should not be carrying their upper sails. If hit by one with a trainee at the wheel, it will probably prove more expedient to bear away as it takes an experienced helmsman to bring a square-rigged sailing ship close to the wind without being taken aback, particularly in darkness.
Brigs, being well balanced vessels, will heave to with few problems. When shortening sail, the action of lowering the three upper yards will not only reduce the sail area and the centre of pressure, but in doing so will also lower the centre of gravity. All sailing ships need more ballast than ships powered by engines to enable them to stand up when under sail. However, in calms and when running before a strong wind, this weight in the keel can produce a roll period equal to that of the swell, with very uncomfortable results. There were instances in the past when this became so pronounced in calms that the whole rig gave way and the vessel was dismasted. The brigs have auxiliary engines, so in calms this can be avoided by turning on to a heading that increases the roll period so that it no longer matches that of the swell. Similarly, when running down wind excessive rolling can be reduced by tacking 10 degrees or so on either side of the intended course.
The brigs are well proportioned sailing vessels which the crew will find comfortable in a seaway, easy to handle under sail, and with a strong rig that will allow them to be driven as hard as their Masters feel expedient. In the past, brigs were considered by seamen to be the most efficient of all square-rigged sailing vessels, well balanced, powerful vessels going to windward and highly manoeuvrable in narrow waters. I believe that the STA brigs will live up to the reputation of their predecessors and prove to be good sail training vessels.
This article is from the April / May 2000 issue of the
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