3. The heaviest and thickets oils are most effectual. Refined kerosene is of little use; crude petroleum is serviceable when no other oil is obtainable, or it may be mixed with other oils; all animal and vegetable oils, such as waste oil from the engines, have great effect.

4. In cold water, the oil, being thickened by the low temperature and not being able to spread freely, will have its effect much reduced. A rapid spreading oil should be used.

5. A small quantity of oil suffices, if applied in such a manner as to spread to windward.

6. It is useful in a ship or boat either when running, or lying-to, or in wearing.

7. When lowering and hoisting boats in a heavy sea the use of oil has been found greatly to facilitate the operation.

8. The best method of application appears to be to hang over the side, in such a manner as to be in the water, small canvas bags, partly filled with oakum, capable of holding from 1 to 2 gallons of oil, the bags being pricked with a sail needle to permit leakage. The waste pipes forward are also very useful for this purpose. Any method of using oil will answer that produces a slow and steady flow.

9. Crossing a bar with a flood current, to pour oil overboard and allow it to float in ahead of the boat, which would follow with a bag towing astern, would appear to be the best plan.

On a bar, with the ebb current running, it would seem to be useless to try oil for the purpose of entering.

10. For boarding a wreck, it is recommended to pour oil overboard to windward of her before going alongside. If she is aground the effect of oil will be depend upon attending circumstances.

11. For a vessel riding in bad weather to a sea anchor, it is recommended to fasten the bag to an endless line rove through a block on the sea anchor, by which means the oil can be diffused well ahead of the boat, and the bag readily hauled on board for refilling, if neces

sary.

The use of oil being of comparatively recent origin, much remains to be learned concerning the methods of application. Mariners are invited to forward the results of their experiences with the use of oil to the Hydrographic Office or any of its branch offices.

CHAPTER I.

GENERAL INFORMATION.

Plan.-H. O. Publication No. 108A, Great Lakes Pilot, Volume I, commences at Detroit, describes and gives sailing directions for Lake St. Clair, St. Clair River, Lake Huron, Georgian Bay, North Channel, Lake Michigan, and Lake Superior.

It connects at Detroit with H. O. Publication No. 108B, Great Lakes Pilot, Volume II, which describes and gives sailing directions for the remainder of the Great Lakes and the St. Lawrence River to Montreal.

Great Lakes. While it is convenient to divide the Great Lakes Pilot into two volumes, to be properly understood the Great Lakes region must be considered as a single waterway. The Great Lakes are a series of inland seas whose aggregate area, about 94,100 square miles, exceeds that of any other series of fresh-water lakes in the world. They occupy depressions that are separated by low reliefs only from the drainage system of the Mississippi River and from the depression of Hudson Bay, the entire drainage area amounting to 288,245 square miles.

Their elevation ranges from about 600 feet in Lake Superior to 234 feet in Lake Ontario; but from Lake Superior to Lake Erie the fall is only 36 feet, so that almost the entire descent is accomplished in the Niagara and St. Lawrence Rivers. To overcome these falls various canals have been constructed which determine the dimensions of the lake carriers and give them their well-known characteristics.

Lake level.-In late years there has been a serious lowering of the lake level which has caused great concern, for the lessening of the draft available for a large lake carrier by 1. foot means a 10 per cent loss in cargo carried. For this reason there is considerable opposition to an enlargement of the Chicago Drainage Canal with a consequent increase in the amount of lake water carried off.

Climate. The climate of this region is favorably affected by the Great Lakes, which moderate the cold in winter and the heat in sumThis permits the extensive fruit culture of this section, particularly in the Lake Erie region.

mer.

Fisheries on the Great Lakes attain considerable magnitude, which is apt to increase in the future; Georgian Bay supplies a large amount of fish to the markets of the United States.

24

LAKE HARBORS

-OUTLETS- -TRIBUTARY CANALS- -COMMERCE.

Lake harbors are nearly all shallow, and are subject to constant silting, which requires regular dredging. They are usually protected by breakwaters, sometimes provided with stilling basins, with piers projecting from river banks to assist in scouring the harbor of silt. The water fronts are solidly built up with elevators, coal trestles, and warehouses, and provided with rails furnishing close connections between railway and water transportation.

Outlets to the ocean are (1) via the Erie Canal to Albany and New York Harbor; (2) via combined rail-and-water route to St. John, New Brunswick, Portland, Me., and Boston, Mass.; (3) via the St. Lawrence to Montreal. The Erie Canal as recently improved provides passage for 1,000-ton barges, which necessitates breaking cargo at Buffalo and again at an ocean port. The canals of St. Lawrence provide unbroken passage to small vessels. The delays incident to these routes have led many to advocate enlarging the St. Lawrence canals so that ocean-going steamers can dock at any of the ports of the Great Lakes.

Another plan proposed is an enlargement of the Chicago Drainage Canal to connect the Great Lakes with the ocean via the Mississippi Either project would involve large expenditures, but the decreased cost of traffic would probably repay the initial cost very quickly.

Tributary canal systems include the Erie, the Ohio, and the the Chicago Drainage Canal, in the United States, and the Ottawa Canal, Rideau Canal, Trent Canal, Murray Canal, and Chambly Canal, in Canada.

These systems, connecting as they do the St. Lawrence, the Hudson, the Ohio, and the Mississippi, are bound to form a large part in any well-developed system of inland waterways.

Transportation.-Almost one-half of the gross tonnage of the United States merchant marine is employed on the Great Lakes, and a greater tonnage annually passes through the Detroit River than enters and clears in the foreign trade of the Atlantic and Pacific ports of the United States. The traffic of the canal at St. Marys Falls exceeds that of the Suez Canal.

Transportation on the Great Lakes excels that on the ocean in rapidity, economy, and efficiency. The richest part of the United States is tributary to the Great Lakes and offers for cargo the products of farm, forest, and mine. The bulkiness of the products and the short navigational season on the Great Lakes have made rapid cargo handling a necessity and this necessity has produced terminal facilities in all the large ports that include elevators, warehouses, wharves, belt-line railroads, tugs, barges-in short, all the modern appliances for the transshipment and storage of bulky cargo.

Commerce. The bulk of the traffic is eastbound, consisting in the main of wheat, lumber, and ore from the upper lakes. The west

bound traffic is principally coal and factory products from New York, Pennsylvania, Ohio, and West Virginia, and imports from Montreal. This has made the Lake Erie ports important exchange points for east-going and west-going products. The amount of United States wheat available for export is continually decreasing, the amount of Canadian wheat available for export is increasing and this will increase competition for east-bound cargoes of wheat and will influence the routes.

Ice.-Ice closes the Lakes to navigation for a certain period each year. The average season of open navigation is 225 days per year. Efforts are being made to extend the season by the use of ice breakers. Ferries used in connection with certain railroad systems are built to crush their way through the ice in an effort to maintain a year-round service.

Traffic on the Great Lakes resembles railroad traffic in density and schedule. Vessels are driven almost like locomotives in order to make the most of the open season. They are loaded and discharged in hours, and it is not unusual for one of the largest carriers to arrive at a port, load to capacity, and depart within six hours. As a result of this combination of terminal facilities and specially designed cargo carriers, the freight rates are low.

Lake carriers.-The dimensions of the vessels on the Lakes are fixed by the depths of the channels connecting the Lakes, particularly the passage between Lake Superior and Lake Huron and Lake Huron and Lake Erie. At present (1921) St. Marys Canal lock (Canadian), with a depth of 19 feet, a width of 60 feet, and an available length of 900 feet, controls traffic on Lake Superior, Lake Michigan, Lake Huron, North Channel, and Georgian Bay. The channels in St. Clair River and Lake control the entrance from the westward into the lower lakes. In 1921 the controlling depth was 20 feet, so that vessels designed to engage in through traffic between the upper and lower lakes could not exceed that depth.

The Welland Canal, passing vessels of 14 feet depth, 255 feet length, and 45 feet width, controls the dimensions of vessels designed to trade in Lake Ontario and further restricts their size. The various canals on the St. Lawrence have the same controlling dimensions as the Welland Canal, so vessels that can transit Welland Canal may become ocean carriers as well. The new Welland Canal is designed to carry vessels 800 feet long, 25 feet draft, and 80 feet wide. This enlargement will permit vessels of those dimensions to pass from Lake Erie to Lake Ontario, but the principal advantage resulting from the new Welland Canal will be passing vessels of 19 feet draft, and 860 feet length from Duluth or the head of the Lakes to Ogdensburg, N. Y., or Prescott, Canada, from which terminals it will be possible to lighter alongside ocean vessels at