The daily Alaskan., 1915-06-16
OUR GREAT CANAL
How Vessels Cross From Ocean
 to Ocean at Panama.
GOING THROUGH THE LOCKS.

Electric Locomotives Of Unique De-
 sign, With a Cog Rall system, Are
 USsd For Towing PurposOs-ssfO- guarding the Lock WaIIs and GatsR.
 Forty electric locomotives of unique design are used to tow shipping through the huge locks of the Panama canal When the canal was being planned 1t was apparent that the vari- ous winch and capstan systems in vogue for towing ships through exist ing canals and locks would not do at all for Panama. After q thorough study of the entire problem of maneu- vertng ships through the locks at Pan anna 1t was evident that they could not safely proceed through the locks under their own power and that substitute for the ships power should embrace the following requirements:
 Ability to place the ship in proper re- lstion to the lock.
 Capabiuty for keeping the ship in its course.
 Accelerating and retarding the ship without rupturing the lines
 The lines when once attached should be used without change for lockage in flight
 In passing through the canal from the Atlantic to the Pacific a vessel en- ters the approach channel in Limon bay, which extends to Gatun, a dis tance of about seven miles. At Gatun le enters a series of three locks in flight and is raised eighty-fve feet to the level of Gatun lake. It then steams at full speed through the great CT part of the channel in this lake for a distance of twenty-four miles to Bas Obispo, where Ii enters the Culebra cut. It passes through this cut, which has a length of nine miles, and reach es Pedro Miguel, where 1t enters a lock and is lowered thirty feet Then 1t passes through Mlrafores lake for a distance of one and one-half miles until it reaches MiratiOres, where 1t is lowered fifty-fve feet through two locks to the sea level, after which 1t passes out into the Pacific through an eight and one-haIf mile channel.
 The main features of all the lock sites are identical, and the following brief description of the Gatun locks. with special reference to the arrange ment of the towing tracks, ship chan nels, inclines and approaches, gives a clearer conception of the towing scheme in general.
 There are two channels at Gatun. one for traffic in each direction. The channels are separated by a center wall, the total length of which Is O,33O feet. There are two systems of tracks, one for towing and the other for the return of the electric locomotives when returning idle. This, however, refers only to the outer walls. For the cen ter wall there Is only one return track in common for both tue towing tracks. The towing tracks are naturally placed next to the channel side. and the sys' terl of towing ulliZes normally not less than four locomotives running along the lock walls. Two of them are opposite each other in advance of the vessel, and two run opposite each oth CT following the vessel. The number of locomotives is, however, increased when the tonnage of the ship de mands 1t
 Cables extend from tue forward 10 cOinotives and connect with the port and starbOald sides. respectively. or the vessel near the bow, and other cn blcs connect the rear locomotives with the port and starboard quarters of the vessel. The lengths of the various ca bles are adjusted by special winding drum on the locomotive to place the vessel substantially in midchannel When the leading To, omotivGS are start ed they tow the vessel. while the trail Ing locomotives follow and keep the ca bles taut By changing the lengths ot the rear cables the vessel can be guid, ed, and to stop the vessel all the loco motives are slowed down and stopped. thus bringing the rear locomotives In action to retard the ship. Therefore the vessel Is always under complete control quite Independent of its own power, which Is not used. md the dan ger of injury to the lock walls and gates Is consequently very greatly les sened.
 These towing tracks have a specially