The Bulk Canaller

Cargoes

Ever since the early agricultural development of the prairie provinces, grain has been the largest single commodity in the eastbound traffic and as a bulk cargo has been the mainstay of the canal traffic even as far back as 1800. The wheat cargoes originate mainly in Fort William-Port Arthur and are shipped via the Sault Ste. Marie and Welland canals to elevators at ports on Lake Erie and Lake Ontario, such as Port Colborne and Prescott, in large Upper Lake freighters carrying 500,000 bu and up. At these elevators the grain is transhipped to canallers for carriage to Montreal where it is again transhipped to ocean-going vessels for overseas points. Before 1930 all transhipments from Upper Lake vessels had to be made at Lake Erie ports but the opening of the Welland canal in that year enabled the Upper Lakers to continue to Prescott.

The heavy eastbound grain traffic is now partially balanced by a relatively new westbound cargo. This is the Labrador iron ore which is being shipped largely by ocean-going vessels from the ore port at Seven Islands to Contrecoeur, Que., whence it is being carried by canaller to Hamilton and Lake Erie ports.

Imported special type ores for the U.S. steel industries are also transported via the canals, having been discharged from ocean-going vessels at Sorel and Montreal.

Before the Labrador iron ore traffic development in the postwar period the bulk traffic through the canals was almost entirely eastbound giving rise to an uneconomical situation when ships had to return west in ballast.

General Arrangement

Fig. 12 Bulk Canaller Thordoc Ex Casco; Built 1927

The bulk cargo vessels which are employed in the grain and ore trades have always formed the largest part of the canal fleet and several vessels representative of their period are shown in the accompanying illustrations.

The Calgary, built in 1912, is typical of the early bulk freighters for the new canal. This particular vessel was one of the first twin-screw Diesel canallers (9).

Fig. 12, shows the Thordoc ex Casco built in 1927 and typical of the many single-screw steam canallers built in the period 1927-1929, the raised quarterdeck being used to control trim in the deep-load condition. Two other vessels of this period are the New York News,

Fig. 13 The New York News; Built 1925

Fig. 13, and the

Fig. 14 The Sandland, Built 1925 Shown with Deck Cargo of Lumber

Sandland Fig. 14.

The Manicouagan renamed Col. Robert McCormick, Fig. 15 and the Iroquois, Fig. 16, were built in 1955 and are two of the most recent bulk vessels built for the canals.

The basic features of these vessels have changed very little since 1912, the general layout being the same in most cases.

The wheelhouse, together with the deck officers' and crew's accommodation, is placed as far forward as possible and the remainder of the accommodation together with galley, mess rooms, and so on, is grouped round the casing aft.

Fig. 16 The Iroquois, Built 1955

Fig. 15 Manicouagan Built 1955, Renamed Col. Robert McCormick

The chief reason for the forward wheelhouse is to enable the wheelsman to see the exact position of the bow when entering locks and channels but it also has some disadvantages, especially in bad weather. In addition, the wheelsman is without a point on which to steer and this has led to the fitting of the steering pole or "spearpole," a light spar about 20 ft long hinged on the top of the stem bar and supported by wire stays. The spearpole can be seen in several of the illustrations.

Fig. 17 Bulk Canaller Belvoir, Built 1955

The inconvenient division of the accommodation into two separate islands, has been eliminated in some of the more recent canallers which have been built with all accommodation aft and with a sunk forecastle as in the Belvoir, Fig. 17. This results in more compact living quarters and allows more space for the forward deck machinery. This type is conned into the locks by a man stationed forward.

Many of the older vessels have an additional deckhouse on the poop deck aft. The need for this house arose as a result of a dispute in 1946 between the crews and the operators, when a three-watch crew replaced the two-watch system which had been used up to that time. In some vessels it was possible to accommodate the additional crew in the existing accommodation spaces but many others required the extra house.

Mooring

The mooring and warping equipment of canallers is specially arranged for maneuvering the vessel through the canal locks and a description of the method of locking will indicate the purpose of the equipment.

As a canaller approaches a lock the speed is reduced and the ship centered on the lock. As the clearance in many ships is only a few inches this must be done very carefully and a good deal of experience is required. As soon as the bow is into the lock the displaced water has to pass through the narrow gap between the lock walls and the ship, so that much more power is required and in fact most ships need "full ahead" in order to enter the lock.

When the ship is partially into the lock, wires are laid out forward from the mooring winches to bollards on the lock wall and the vessel is slowly warped forward and kept central in the lock. At the same time a wire is laid aft from the forecastle snubbing winch through a wire stopper or compressor to the lock wall. This wire is paid out as the ship moves forward until the bow officer judges that the bow is in the right position to clear the swing of the gates. The wire is then clenched in the compressor and the ship stopped.

The warping operations require winches in pairs along the upper deck. These winches can be seen in Fig. 20. In this case they are also used for the cargo gear but in ships without derricks they are placed in pairs close together near the centerline so that one man can operate both winches, paying out on one and hauling in on the other as necessary to keep the ship centered in the lock.

The warping wires are carried out over the ship's side through a special type of roller fairlead known as the Port Colborne fairlead which may be seen in Fig. 20. This type has two rollers mounted in a ring which is free to rotate in a vertical frame mounted in the bulwark or other support. This fairlead was specially developed for use in canals where the lead angle of the wire changes sharply as the locks are drained and filled, the arrangement allowing the rollers to align themselves in any direction. The Port Colborne fairlead has superseded an older type in which a roller in a pivoted frame has only partial movement. Many of the older vessels still have this type.

To enable the crew to get ashore easily and quickly to handle the lines at the locks a pair of landing booms is fitted. These are spars hinged at the corners of the forecastle deck and supported by guy wires. When a downbound ship enters a flooded lock a deckhand swings himself ashore on the "monkey line" attached to the end of the boom and when the ship is unlocked returns in the same way.

The anchor pockets, another special feature arranged for the locks, may be seen in the illustrations. A seagoing vessel of this size would not normally have this refinement but the forward shape of a canaller is so full that anchors stowed in conventional hawsepipes would be likely to foul the lock gates and must therefore be housed entirely inside the line of the shell.

Structural Features

In general, canallers are built on a transverse framing system with, in many cases, longitudinal deck beams. The structural details and amount of riveting and welding vary greatly according to the time and place of build.

The transverse framing is mainly used because with bulk-grain cargoes, longitudinal framing leads to lodgment of grain on the frames which is difficult to remove. Several ships are framed longitudinally, being mainly those designed for specific cargoes such as newsprint and not originally intended to carry grain.

The extreme fullness of canallers leads to framing difficulties at the forward end and in many riveted ships a system of cant framing was adopted to avoid excessive bevels of the frame flanges. With welded frames the bevel difficulty does not arise but efficient welds are more difficult to obtain with the shell plating lying at steep angles to the frames and in addition the unsupported panel of shell plating becomes very wide and intermediate panel stiffeners are required if cant framing is not adopted.

The midship body of a canaller presents little difficulty in shell plating, the vertical sides and constant bilge radius allowing easy prefabrication, the ends however, have a great deal of compound curvature and good workmanship is required to produce a fair shell.

Welding on a large scale was introduced to canal vessels quite early and a completely welded vessel, the Franquelin, was completed in 1936. The ships built after the war are, of course, almost entirely welded.

Welded shells have proved to be efficient for canal work as these vessels are often in contact with locks and projecting masonry. In a riveted ship sprung rivets due to bumps are fairly common but welded hulls can be severely deformed without leakage. In many welded canallers dents in the bows just at and below the load line and at the line of the bilge are several inches deep without signs of leakage.

Fig. 18 Midship Section of Standard Bulk Canaller Built 1927-29 by Swan Hunter and Wigham Richardson & Co. Ltd.

Wide hatches are essential for the handling of the varied canal cargoes and for the easy access of elevator hoists. They are usually 28 to 30 ft wide, which is large for a ship of 43 ft 6 in. beam; the length/breadth ratio however is low and adequate longitudinal strength can be obtained without the deck plating being too thick.

Fig. 19 Midship Section of early Postwar Canaller

Canallers are normally built without hold pillars the deck being supported by a system of web frames and cantilever brackets from the web frames and the transverse bulkheads. The deck girders and hatch-side coamings are frequently made continuous throughout the well deck with shallow girders below deck.

Midship sections of two types of canaller are given in Figs. 18 and 19. Fig. 18 is the section of one of the many bulk vessels built in the late 1920's and shows the all-riveted construction used at that time. These ships had solid floors on every third frame with intercostal bulb angle fore and afters between the floors on the bottom shell and tank top. It also will be noted that the hatch coamings consist of 12-in.-bulb angles. These have now been replaced by conventional coamings 24 in. high to comply with the amended load line regulations.

Fig. 20 General Arrangement of Early Postwar Canaller

Fig. 19 shows the section of an early postwar bulk vessel, almost entirely welded, using inverted angle frames and plate floors at each frame. The general arrangement of this type is shown in Fig. 20.

Classification

Up to the amalgamation of Lloyd's Register of Shipping and the British Corporation Register of Shipping and Aircraft in 1949, most canallers were built to the requirements of the latter society. The ships are classed B.S.* with the notations "For service in the Great Lakes and River St. Lawrence," or for "Great Lakes and coasting services," etc., according to their service. Since the amalgamation the ships have been built to the corresponding class of Lloyd's Register.

Conduit Bilge

The walls of the canal locks are built with a slight slope and the portion of the ship most likely to come into contact with the wall is that at and just above, the upper turn of the bilge. The double-bottom height is normally kept to the minimum allowed by classification rules so that the double bottom, even if extended to the shell without a sloped margin, would not protect the vulnerable part of the shell. The "conduit bilge" arrangement, a patented system which was introduced in the Buckeye State in 1929 for service in the New York State Barge Canal, provides this protection and at the same time provides additional ballast capacity without removing useful cargo space. It also results in a much cleaner arrangement in the bilge, without brackets to interfere with the unloading of grain cargoes. The shorter span between the deck and the conduit top results in a shallower frame and a much stiffer side panel.

In its original form the conduit bilge was part of a form of construction specifically designed for the carriage of grain, sugar, and the like. The upper corners of the hold space, which are normally void when a bulk cargo is carried, were removed and the shell and deck beveled off at an angle of 45 deg. This effected a reduction of steel weight due to a smaller sectional area and, in combination with the conduit bilge, further reduced size of side framing.

Fig. 21 Outline Section of "Red" Barges Built in 1933

In the early 1930's several barges were built with this form of construction, a line diagram of which is given in Fig. 21. These vessels were built as barges in an attempt to overcome economic difficulties resulting from delays in the locks and at elevators. The barges being of simple construction and unpowered were economical to build but proved uneconomical to operate. Within a few years of building they were fitted with a lowpower twin-screw Diesel installation and can now navigate the canals without tugs.

Fig. 22 Barge Redfern, Built on Conduit-Bilge System

A photograph of the Redfern, one of this type is given in Fig. 22. This vessel was later fitted with an aluminum deckhouse aft, shown in Fig. 23, to provide accommodation for increased complement.

Fig. 23 Aluminum Superstructure of the Redfern

The conduit bilge arrangement has been fitted, in various forms in several canallers, one of the special forms being shown in Fig. 24 where the height and width are arranged to suit a standard roll of paper.

Fig. 24 Outline Section of the Chicago Tribune

Ballasting

The average canal vessel, having machinery aft and very full lines forward is a difficult vessel to trim when in a light or partially loaded condition. This is further complicated by the fact that in order to obtain the maximum cubic no space except the fore peak and the conduit bilge if fitted, can be allocated as a permanent trimming tank. A near even keel trim is, of course, essential for a vessel passing through the locks and to obtain this an unusual method of ballasting is adopted. Flooding valves are provided in the tank top or, where a conduit bilge is fitted, in the side of the conduit bilge tank, allowing the holds to be flooded as required for trimming. In riveted vessels the hold divisional bulkhead is made watertight up to about 8 ft above the tank top. The effect of this large free surface is not serious as, owing to their form, canallers have adequate stability.

The tanks, double bottom, fore peak, and conduit bilge are provided with the normal pumping arrangements.

Some canallers at deep load, particularly when down to the 16-ft 6-in. coasting or lake draft tend to trim by the head. This is due partially to the shift aft of LCB as the very full stern becomes immersed and partially due to the fact that the LCG of the cargo space is so far forward. This is particularly so in steam-powered canallers which usually have longer machinery spaces than Diesel-powered vessels. As a result many steam vessels have a raised quarter deck enabling the full deadweight to be carried while maintaining even keel trim.

Steering

A canal vessel spends most of its life in the narrow and restricted waters of rivers and canals and its steering qualities are therefore of considerable importance. The hull form of canallers is, of course, not good from this point of view. Large rudders are therefore necessary but somewhat difficult to achieve as the swing of the lock gates makes it impracticable to have the rudder extending beyond the end of the vessel. In some canallers this problem is partially overcome by using higher powered motors on the steering gear than normally would be necessary, thereby increasing the rudder speed.

A number of canallers have been built with twin screws and twin rudders which produce a marked improvement in the steering characteristics. This improvement is expensive and was fitted in a relatively small number of canallers.

The majority of the older vessels were equipped with steam steering gear. The engine was fitted in the steering-gear compartment aft and controlled from the bridge by a shaft running below the upper deck or by a wire transmission running in sheaves.

There has been some discussion about the fitting of activated rudders but so far no canallers have been so equipped.

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This paper was presented at a meeting of the Society of Naval Architects and Marine Engineers and is reproduced with permission.