The STX AH 04 Skandi Skansen in Lerwick back in 2012 photo by Paul Moar.

On the south side of the channel into Aberdeen harbour there is a capstain set on the end of a short mole. There is no graffiti decorated plastic covered explanation to tell the general public about the materials used in its construction, the date of its installation or its use, but a mariner standing next to it and looking out to sea would summise that it had been placed there to heave sailing vessels up the channel. It has probably been there for 200 years.

The same sort of capstains can be seen in ilustrations of jolly jack tars heaving in the anchors of warships on the 19th century, and indeed up until recently the navy still used a version of the capstain to get the anchor chains into the chain lockers.

The owners of commercial vessels on the other hand soon identified that the forecastle of a ship is a wasted space in terms of cargo carrying and therefore it should be a short as possible. Consequently the means of getting the chain into the chain locker should be compact. This required a vertical winch set aft of the hawse pipe and over the spurling pipe. For good measure drums were attached to the ends of the gypseys which helped with the deployment and recovery of mooring lines.

At the same a time as this development of anchor deployment and recovery means was taking place, the steam engine and then the diesel engine were invented. Tugs took to the seas in order to assist with the docking of ships, incidentally making redundant the capstains in the entrance to Aberdeen harbour, and finally salvage tugs with their own towing wires reeled onto drums on the afterdeck were constructed. The development of marine winches was therefore well advanced when the first column stabilised semi-submersible the Ocean Driller entered service in 1963, bringing with it the need to deploy several anchors from the same vessel.

The marine part of the industry tackled this new problem in a variety of ways. There are tales of tugs laying anchors using a hang-off point on the bow, and certainly the Americans approached the problem by bolting down portable winches powered by V8 diesels on the forward ends of what were otherwise a conventional supply vessels.

The naval architects employed by the shipowners, shipyards and design houses of America and Europe were looking for a marketing advantage for their ships and therefore were trying to solve the problem. By 1972 Tidewater owned four "Supply- Towing" vessels equipped with a winch capable of pulling 200,000 lb (100 short tons) and in Europe a number of shipowners developed and brought into service anchor-handling tug supply vessels.

Typically by 1972 the Maersk Company had seven 4000 bhp anchor handing supply vessels in service, each fitted with a double drum waterfall type winch driven by a Scania diesel engine. These winches claimed 100 tons (long tons) pull, and by 1974 they had built a further seven vessels of more than 6000 bhp, each equipped with a Brattvaag low pressure hydraulic winch with 100 tonnes pull. The drums of these winches, one tow drum and one workdrum, were capable of storing 3550 ft (1082 meters) of 50mm wire.

UK owners including Offshore Marine and OIL were also developing new vessels with winches of similar capabilities from a variety of suppliers. OIL, financed by the Ocean Group and Inchcape built four anchor handlers in Holland. These ships made up the BP marine service which anchored the Sea Quest in 300 ft of water in the Forties Field. The 300 foot water depth was no problem, but due to the poor holding the vessels were required to deploy a variety of hardware on the end of the moorings, which, although scientifically shaped, in reality held the rig in position by means of sheer weight.

At this stage all winches were provided with a single tow drum with approximately 1000 meters of some suitable dimensioned wire wound onto it, and a single workdrum onto which numbers of pennants which made up the string between the anchor and the mooring buoy  were reeled. Anchor-handler crews, who were learning this job from scratch, were beset with endless problems relating to these pennant strings. If the job was starting from scratch, the wires would be delivered to the ship in coils and they would then have to be reeled onto the workdrum with some tension, connected together with 50 tonne shackles. Unless some special effort was made to tighten up the wraps, the first time the ship pulled away with an anchor on the end of the wire, the top wrap would bury itself under those beneath making it impossible to lower the anchor to the seabed.

Even  if this did not happen the wire wrapping over the top of the threads of the shackle pins would make it impossible to get the nuts off, resulting in two 36" wrenches becoming an essential components of the tool kit.

At this point we should spare a thought for the operators of the winches on these vessels. They were required to stand for the duration of the anchor job, out in the open twirling the wheels and pulling handles, not unlike 1950s British Rail signalmen, but getting much colder.

Smit-Lloyd, whose designs never changed, except in detail, throughout the life of the company, identified this particular problem and put the winch driver in a small hut attached to the aft end of the accommodation, just forward of the winch. OIL and Wimpey followed suit in the latter case the reflection of the Smit-Lloyd design, not being limited to the winch drivers house.

In 1975 the arrival of the UT704 revolutionised almost all aspects of the business, one of the changes being to put the winch driver in the Pilot House next to the Master, both of them facing aft in adjacent seats with their controls to hand, able to look down on the working deck and the winch from their lofty position.

The next major change in winch design and operation was the development of the twin workdrum. The first ships to be fitted with twin workdrums might have been the OIL anchor handers Oil Harrier and Oil Hustler which entered service in 1976. The winches were built in Holland by Van de Giessen. Unusually they were electrically powered and when paying out relied entirely on the brakes for control. Unfortunately designers has miscalculated the trend in mooring system development and the workdrums, with a theoretical capacity of 600meters of 56mm wire proved to be too small for the efficient deployment of anchors in 300 meters of water using a permanent chasing system.

By the end of the decade all the lessons were being learned, and Maersk, who had been pretty quiet for the previous five years returned to the fray with yet another fleet of superships, the first being the Maersk Retreiver and the Maersk Ruler. These ships were equipped with Brattvaag triple drum waterfall winches capable of 270 tonnes pull and of storing 1200 meters of 72mm wire on each of their three drums.

Readers might be wondering what was happening in other areas of the world. The answer is, very little. The Americans were moving their rigs using a variety of small craft including barges and tugs. Typically a set of six identical 180 foot anchor-handlers built for Petromar by Halter Marine in 1983, were still equipped with Smatco waterfall winches, powered by GM diesels and with a capacity of 945 meters of 54mm wire on each drum. These winches were capable of 136 tonnes pull on the first wrap. The Brazilians, now the world leaders in the design of deep water mooring systems, then had no idea of what might be achieved with a decent ship.

By 1983 double workdrums were more of less required in Europe and the British company Star Offshore demonstrated the capabilities of the equipment by fitted what appeared to be a wildly oversized winch to what was nothing more than an improved UT704. The winch had 300 tonnes pull and could easily store 1000 meters of 54mm wire on each of the workdrums. This conservative estimate was dramatically exceeded in 1984 when the ship, the Star Polaris, recovered almost the whole of a 1500 meter mooring of 72 mm diameter, which had failed at the fairlead of the Pentagone 84, onto one of its workdrums. The mooring was subsequently reconnected to the rig and the anchor redeployed.

Two slightly improved versions of this vessel with exactly the same winches, the Star Sirus and Star Spica entered service in 1985 and were immediately pressed into service, mooring rigs with buoy and pennant systems in 700 meters of water west of Shetland. Despite the 300 tonnes pull at the first wrap it was still difficult to pull anchors aboard in this depth of water, because the pulling power of a full drum is considerably less. Recognition of this difficulty resulted in much more powerful winches being installed in later years.

Meanwhile, in Copenhagen, Maersk unveiled a completely revolutionary design of anchor-handler, the Maersk M class. The winches on these vessels built by Rauma Repola in Finland had 300 tonnes pull and, uniquely, were provided with two tow drums and two work drums each with a capacity of 1200 meters of 65mm wire. The winch houses on these ships completely enclosed the winch itself so that the Master and Chief Engineer viewed the drums by means of close circuit television. However it should be noted that at this time experiments with spooling gear had been almost universally unsuccessful and so spooling onto the drums was carried out by the deck crew pulling the wire from side to side using tuggers. Of course almost all the ship we have mentioned so far are still in service, so this is still the technique which is used.

In the late 1980s there was another breathing space as the oil price plummeted and as a consequence all types of activity were reduced to a minimum. During this lull Maritime Engineering developed the ME606 which appeared as the Maersk P class in 1991. This ship type was fitted with a Brattvaag winch with an SWL of 350 tonnes and workdrums capable of storing 2000 metres of 77mm wire. It must now be obvious that anchor-handlers were being developed to do more than move semi-submersibles, and the change was probably down to the Brazilians who had more or less accidentally hired one of the Maersk fleet and found that they really had the ability to go deeper.

To make the most of this knowledge they hired the Maersk Provider which was enhanced for its Petrobras contract with a winch of extremely large dimensions. It was fitted with the largest Brattvaag winch to date which had an SWL of 450 tonnes and two workdrums capable of storing 1500 meters of 109mm wire. She has been engaged in laying deep water moorings ever since. In 1996 they hired the Maersk Chieftain a large but now ageing VS476 which was modified to deal with the polyester rope which has the disadvantage of having a very large working radius and so requiring a very large or modified roller and a large winch drum.

The Bazilians led the way into deep water, stimulating the development of other vessel designs which would deploy moorings in depths of more than 2000 metres. Ulsteins developed the UT 722, which was intended to be a sort of bread and butter anchor-handler, and the UT731 and 740 which were intended to be construction vessels fitted with enormous winches. These latest winches  have of course reverted to the single workdrum, although some have two tow drums.

Typical is the Farstad UT722 Far Senior which entered service in 1999. It has a winch winch capable of pulling 400 tonnes at the first wrap. The work drum and a tow drum have a combined capacity of nearly 6000 meters of 96mm wire. Each of the drums is divided into a large section and a small section so that connections will be so positioned that they will not damage the main part of the wire. Spooling gear has returned but it is controlled from the bridge and each set of spooling gear is provided with a CCTV pointing towards the drum, so that loose turns can be minimised.

In America Halter Marine produced a number of designs. The HLX255 255 ft anchor handler Seacor Vanguard was delivered by the yard in October 1998. This vessel  could store 41,200 ft of 3.5" wire on its drums and uniquely was provided with a traction winch. Traction winches had so far only been used in the offshore industry as a means of tensioning moorings on semi-submersibles while actually storing the wire in the pontoons. They consist of two closely positioned drums with the mooring wire running from one to the other. Hence when operational the wire is always at the first wrap and so the as the mooring is recovered the maximum pull remains available.

Apparently taking board all the lessons identified in this article, Ulstein Verft developed the A101, the first anchor handler designed by the yard after the sale of all other parts of the business to Rolls Royce. The first manifestation of this design was the Olympic Hercules for which Rauma Brattvaag provided the winch. Following what might be called the "deepwater configuration" this winch has two tow drums capable of storing between them 2700 metres of 83mm wire, and a single work drum with a capacity of 2000 metres of 109mm wire and capable of pulling 500 tonnes. Uniquely the vessel is provided with two secondary drums with 170 tonnes pull, capable of holding 1600 metres of 8 inch synthetic rope.

It may be worth mentioning that the popularity of low pressure hydraulics as an operating medium for these winches has resulted in very long lead times which sometimes exceed the building time for the ships. As a result we there are designs of electric winch, which are being operated extremely successfully in deep water. In America when this article was originally compiled in 2002 the Laney Chouest was being built in conditions of extreme secrecy. This vessel was claimed by Edison Chouest to be the largest in the anchor-handler yet built, and was due to enter service in September of that year. The design of the anchor-handling winch continues to determine the effectiveness of the ship on which it is mounted and so it would have been the winch which determined the effectiveness of the Laney Chouest.

Since then, as a 2016 update, only a few vessels have exceeded the capabilities of the A101, but prominent of them may be the STX AH04 built by the company which is now VARD. This vessel claims 36,000 bhp using hybrid technology, and apparently has a work drum with the capacity of 18,700 metres of 76mm wire and a tow drum capacity of 6,700 metres of wire of the same dimensions. Havyard have also designed a ship which claims to be able to store sufficient fibre rope to carry out the complete mooring operation for a semi-submersible, however, although this ship was due to enter service some years ago we have yet to see it (I think).

 
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