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DEVOTED TO EVERYTHING AND EVERY INTEREST CONNECTED OR _ ASSO- CIATED WITH MARINE MATTERS ON THE FACE OF THE EARTH. et, Published monthly by The Penton Publishing Co. CLEVELAND. BOSTON. (cc.cg ccs soe ces 73-74 Journal Bldg. BUGEALO...<-, i ise... cs +1932 Ellicott Sa: GHICAGO ioe. ed see 1328 Monadnock Blk. CINCINNATIR. c<3:.s First National Bank Bldg. NEW. YORK. eo cc cess < 1005 West Street Bldg. PITTSBURG. 2 soc st csere aos 'o one 510 Park Bldg. SHATILE:.... eee eee. 302 Pioneer' Bldg. Correspondence on Marine Engineering, Ship Building and Shipping Subjects Solicited. and Mexico, Foreign, $2.00. 10°. cents: Subscription, U. S. annum. Canada, $1.50. § Single copies, U. S. and Mexico, Elsewhere, 15 cents. Change of advertising copy must reach this office on or before the first of each month. The Cleveland News Co. will supply the trade with the Marine Review through the regular channels of the American News Co. European Agents, The International News ompany, Breams Building, Chancery Lane, London, E. C., England. Entered at the Post Office at Cleveland, Ohio, as Second Class Matter. April, 1909. THE PANAMA CANAL AND THE NAVIGATOR. Although the type of canal at Pana- settled in favor of the lock system there contin- ma is probably definitely ues to be more or less agitation and discussion of the subject not only in the daily press but to some extent in the technical, though it must be said that the latter almost unanimously sup- port the decision in favor. of the lock type. from a few engineers whose opinions . the weight to which they seem to think they were entitled The opposition to it comes chiefly were not given interested in and some of which are methods such special of prosecuting work and which methods they advocate as a solution of the difficulties in the On both sides the dis- cussion has been almost wholly of an engineering nature and confined chiefly to questions of construction. sea level type. The ¢an- al is presumably being built as a ship channel and not principally to settle _ differences of opinion between rival $1.00 «per = tHE Marine REVIEW schools of engineers and it would seem as though its utility, or more properly re for the purpose intended, should cut some figure. So far the men who are to use the channel seem to have been overlooked but it is they, and not the engineers, who will justify or confound the judg- ment of those who determined the type. We need the argu- ments advanced by each side but will consider both types as they affect navi- not here discuss gation. First as to plan. The total length of canal is approximately 50 miles; in the sea. level type about two-fifths of this is made up of curves, in the lock type about one-seventh. In_ the type these curves are sinuous; in the sea_ level lock type they merely represent the 'center line of the canal at the inter- section of straight portions, or ranges; in actual navigation there is practically none, because the ship is kept steadily on one range until she closes the range the shifts of wheel occur the channel is on next course, and where these widened by the suppression of the in- terior angle to give abundant room to swing or pass another ship. It is impossible to steady a ship on a constantly changing course, even in daylight, because there is nothing to steady her, leaving out of the question the influence of bottom drag of which we will speak later, and in this the army engineers who have had the bene- fit of long experience in laying out, constructing and maintaining ship chan- nels as actually demanded by naviga- tion, have evidenced the value of. their experience. Navigation of such a chan- nel at night, when even the bank is not visible' is entirely mmpossible, where- as straight reaches with simple range lights are as easily negotiated by night as by day, so long as the lights can be picked up, Of oJ course ranges on curves are not fea- even with a glass. sible and lighted buoys in a curving channel are altogether impracticable. In width of channel the proposed sea 'level is little a continuous ditch, with a bottom width of 150 ft. The surface width has no bearing on type more than the question whatever except in so far as it affects the flow of water past the ship, which we will discuss later. The lock type has a least bottom wi ae 300 ft. and this for only about eight miles; for about 22 miles 500 ft. width | and for about 20 miles across Gatun Lake, as the water impounded by the great Gatun dam is called, it will pe from 800 to 1,000 ft. wide. These Widths allow even in the shallowest Portions, of a considerable amount of swing, and human power has not yet been able to prevent this swing in narrow or shal- low channels, even with no current. The narrower the channel the greater the tendency to swing, and as the ship always makes for the nearest bank, when "hunting" is once begun, it becomes jn- creasingly more difficult to arrest, be- cause of the increased angle of helm necessary to steady her. Passing other ships in such a channel is a matter of most serious difficulty, hécatee the cross section of the two ships is such a large proportion of the total channel sec- tion that violent disturbing eddies and currents are set up, chiefly by propeller action, and it is very doubtful indeed if two 60-ft. beam ships, with the most careful and deliberate each . other in a 150-ft. channel without rub- bing. handling, could pass Anyone who has ever watched the effect on. the water level in a nar- row channel of even a slowly working propeller with a deep ship will read- ily understand the difficulty. Further, the width room for a ship with temporarily dis- great provides ample abled engines or steering gear to lie off the with the sea level type a ship must be anchor whereas tO atl ranges, kept moving or blockade the channel. Second, as to depth. The sea level canal proposes a depth of 41 ft. and if the plans advocated by some were fol- lowed, this would oniy be at high tide and subject to a tide range of 10 it The lock.type provides a least depth ao AS ft Lake, a stretch of about it waries irom=<45° to,» 70) it. speed due to reduced bottom drag will be very considerable, not omly by rea son of the reduced resistance but also the very much better steering possible with an additional 4 ft. of water. Atlow water the channel depth would be te duced to 31 ft., not even sufficient t0 float many of the ships which would and across Gatun 20 miles, The difference 1