- The background to the tea trade
- Chinese silver
- Treaty of Nanking
- British-built clippers
- Ocean Steam Ship Company
- The homeward passage
- Development of the ships
- The way of a ship
- A comparison of hull forms
- Development of the clipper bow
- Development of the upper stern
- Headworks and upper stem
- Disadvantage of Aberdeen clippers
- Comparison of sizes
- Hull Construction
- Construction of iron hull
- Composite construction
- Proposed tea clipper
- Ornamental deckwork
- Ornamental deckwork
- Miscellaneous fittings
- Full deck height poop
- Sail plans
- Details of tops
- Masts and spars
- Iron yards
- Steering Gear Arrangements
- Windlass and Forecastle Arrangement
- Fife Rails and Bitts
Windlass and Forecastle Arrangement
Up to the 19th century naval ships brought in the anchor cable (hemp) by means of a capstan operated on one or two decks, this also being the only machine for moving or hoisting any heavy weights. Merchant ships also had capstans, somewhat smaller and chiefly used for warping into berths. The anchor cable was brought in by means of a windlass, along horizontal barrel operated by handspikes inserted into holes. This barrel, in small ships, was secured at each end in heavy sockets built against the bulwarks, and in larger ships in sockets or holes in heavy wooden posts (carrick bitts) which had strong knees to the deck on their forward sides.
Chain cables had been in use since the first decade of the 19th century, with studded links on some of the larger Indiamen, and by the advent of the American clippers were in common use..
With the ship at anchor the strain on the cable was taken by the turns on the windlass barrel which was prevented from unwinding by a heavy iron plate ratchet (pawl) from another strong post, which dropped by gravity into an iron cogged rim around the middle of the barrel. Sometimes there were up to three of these pawls of varying lengths above one another. The windlass thus could only operate normally in one direction, bringing the cable aboard and not letting it go. When a ship was coming to anchor an estimate had to be made beforehand of the approximate length of cable required and this was brought up from the cable locker. The end of the cable was led over the top of the windlass barrel from aft with two complete turns and then forward through the hawse pipe and shackled to the anchor ring. The full length of required cable had now to be pulled around the windlass drum and laid along the deck in long loops until the turns around the windlass were at the end of the required length, or as nearly so as could be estimated. When the anchor was let go, the cable along the deck would run out until it was stopped by the turns around the windlass, which were left slack to avoid a sudden shock. Any additional length required had to be eased around the drum by means of long hooks, and additional hooks with two prongs were hooked onto links of the cable and attached to an eyebolt on the centre pawl bitt to help ease the strain on the windlass when riding at anchor .
The wooden windlass drum had iron whelps around it which were renewable and varied in shape, their purpose being to protect the wood and also grip the cable. Sometimes the last length of cable might pull around the windlass in a shower of sparks before being held tight, and when this happened it was necessary to keep the turns around the windlass free of each other, otherwise they could override,jam and possibly break.
To prevent this, stout iron bar hoops called normans were inserted into holes in the upper whelps, straddling each separate turn. The hoops and the windlass remained stationary, locked by the pawl. The period of the 1830s and 1840s was prolific in the invention of mechanical gadgets for ships.
By about 1832 the old method for turning the windlass drum by handspikes was improved upon, no doubt because of the increasing use of chain cable. This was effected by an invention whereby two travellers with ratchets turned iron cogged rims each side of the pawl rim, by alternately moving up and down, the motion being supplied by thwartships hand levers pulling purchase rods . This arrangement remained in common use for large ships until the late 1850s, and indeed into the present century on some vessels. Other closely similar ideas followed, including one in which each traveller was rotated by pulling on levers rather like the old handspikes but without the necessity of withdrawing them after each pull. Some of the larger American clippers increased the manpower of the thwartship hand lever type by using a short centre bitt with the crosshead rocker close to the forecastle deck level. From the crosshead a long iron shaft ran along the deck in bearings and from it about three additional sets of levers were angled upwards, thereby enabling more men to operate it.
About the same time that the hand lever windlass with traveller came into use, cable compressors were introduced as an improvement on the chain hooks to hold the cable in addition to the windlass. These, were heavy iron pads with grooves along their centres, fixed to the deck just inside the hawse holes or pipes. The chain cable led over the pad and could be locked in place by dropping a thick, hinged iron bar over the flat of a link and into a slot" The final design of windlass was thought out in general principle by John Avery in 1855, but brought into production by two well known manufacturers Harfield and Emerson Walker in 1858-60. It was operated by a capstan with bevel gears (A very's had levers on a vertical shaft) , and the old wooden barrel was replaced by strong metal cable lifters over which the cable fitted snugly into shaped recesses. The earliest form is shown on the drawing of the patent windlass and was considerably elaborated later by the addition of friction brake drums and eventually by a steampowered drive from a donkey boiler. This, however, was just after the end of the British tea clipper period. The American tea clippers kept to the wooden barrel type as they were out of the trade by the time the patent windlass was in vogue.
With the older form of wooden windlass, the anchor cable led some distance aft along the deck, perhaps as far as the forward deckhouse, and then went down to the cable locker in the hold through a chain or navel pipe. The deck planking under the lead of the cable was thickened or covered with sheathing boards. The patent metal windlass sometimes had this arrangement also, but as the cable only led over the gypsy once, it was held down on it by passing under an iron deck roller just aft of the windlass. When the patent metal windlass was used the more usual arrangement was to have the navel pipe immediately under the gypsy so that the cable went over the top and then straight down to a chain locker situated nearer the bow.
The iron and composite clippers introduced watertight plate bulkheads at the bow and stern, the foremost one, the collision bulkhead, serving as one side of a chain locker. Ships with very fine fore ends would endeavour to have the weighty chain lockers as far from the bow as convenient.
The arrangement of the forecastle deck was largely dependent on the position of the windlass, and the width of the windlass drums was in turn dependent on the distance apart of the hawseholes, which varied according to the bow being full or fine lined. Contemporary builders' drawings can sometimes be at fault here, as being drawn before the ship was built any necessary modifications were made on the ship during the building and not necessarily altered on the drawings. Reproduction of plans by blueprinting was unknown until the last quarter of the 19th century. An original would be made on white paper and any copies had to be hand-traced on transparent linen. Naval dockyards could afford this sort of work but it is not likely that smaller shipyards could. One shipyard in which my father worked in the 1890s producing steel-hulled fourmasters and smaller steam vessels, had one man who constituted designer, estimator, and draughtsman, and so much for inherited skill, he was Swiss. Within the outline of the basic general arrangement that he produced, each foreman or tradesman in the yard used his own initiative and experience to produce a workable ship, but it was seldom that the plan was brought up to date with the final solutions. The larger yards producing ocean-going steamships would have more drawing office personnel of course, although even here one comes across builders' drawings which do not tally entirely with contemporary photographs, even allowing for later alterations.
To revert to the arrangement of the windlass and the forecastle, the conditions to be satisfied were that there should be sufficient space to walk around the capstan, and to stand each side of the hand levers for the windlass, which resulted in some odd shapes for the anchor deck. The arrangement on the Vision, for instance, gave a semicircular convex end to the deck, the capstan being on the forecastle deck and the windlass operating from the upper deck, the centre pawl bitt being short in consequence. Other ships had the reverse, whereby a concave shaped end to the forecastle deck and a longer centre pawl bitt.enabled both windlass and capstan to be operated from the forecastle deck.
Some of these short anchor decks were only three or four feet high being little more than a platform with barely enough space to crawl under , and with this arrangement the body of the windlass barrel was exposed so that it could be attended to, either completely clear of the deck or with the three bitts built as support into the end of the deck.