VOLUME LXXXX JANUARY-FEBRUARY, 1947 NUMBER 1
[Some words in the fold are only partly readable and are marked with question marks.]
127-foot Mine Planter. Actual construction of the new mine planter, mentioned briefly in a previous issue, is expected to begin in a few months. The ship is to be built by the New York Engineering Company. Both design and construction are under the auspices of the Transportation Corps Board.
Some of the basic principles in design differ greatly from those of the M1 class mine planters. The 127-foot vessel while capable of handling lightweight cable is designed primarily as a mine planter and not a combination cable ship-mine planter. It will be a simple work boat, designed to be highly maneuverable. It will require a small crew and will not he a separate unit but part of the mine flotilla section. Special emphasis has been placed on ample deck space, and selection, design and location of deck equipment. Every effort has been made to speed up, simplify and make safer the job of preparing and planting the mine.
The vessel will be 127 Feet long with a 35-foot beam and 8-foot draft. It will be propelled by two 500-horsepower diesel engines through two Voith-Schneider cyclodal propellers, It is the first ship designed expressly for cyclodal propulsion to be built in this country. The propellers are captured German units. The cyclodal propeller differs radically from the conventional screw type propeller. The direction of thrust is controllable through 360 degrees. Hence, steering is accomplished through the propellers and no rudder is employed on the vessel. The system of propulsion is so flexible that the vessel may be brought out broadside from a dock in a crabbing motion. In tests conducted with a captured German vessel, equipped with cyclodal propellers, the vessel was brought to a standstill from full speed ahead in one-half the ship's length. This type of propeller should make the new mine planter highly maneuverable. Top speed is expected to be about 12 knots.
The deck arrangement includes a working space 30 feet long and 34 feet wide. There will be sufficient distance be tween the cathead and the reels to assure a reasonably level lay, The reel positions are to be equipped with elevators and a stub shaft arrangement so that cable reels may be changed in the mine field without using the ship's crane. The cathead is designed as an integral part of the bulwark. When it is being used, it is pushed out and when not being used. It is raised to form part of the rail. It will not have a long projection on the deck as has the present type cathead, The cathead sheave will be at deck height, thus obviating the use of snatch blocks on the deck for obtaining a favorable lead to the cable reels and capstans. Mines will be planted from davit cranes located both port and starboard just forward of the cargo ports. Those cranes a have power traverse and a 250-Foot whip. These whips operate with the same speed as does the whip on the M1 class mine planters. The davit crane machinery will be located in the 'tween decks space under the working area. A 10-ton crane will be mounted just forward of the house. This crane is to be used to load the planter and is not designed for use while in the mine field. There will be two capstans on the main deck working area, one fore and one aft, both on the centerline of the ship. Controls for the deck machinery are to be located in both the port and starboard sides of the pilot house, next to the cycloidal drive control stands. Thus the master will have control of the deck machinery operators. Moreover, the operators will be able to see the entire working deck and can see over sides of the ship while watching the planting and cable laying operations.
The deckhouse on the main deck will contain the galley and mess room. A steam table will be in the galley so food may be prepared ashore and kept warm until required. The ship's crew and the planting crew can be fed in three sittings. Officers' and crews' quarters will be on the boat(?) deck.
The pilot house will contain three control stands for, cyclodal propellers; one on the port side, one on the starboard side and one amidships, Deck machinery control(?) stands will be located next to the port and starboard cyclodal drive control stands. The ship's radio and chart table are to be mounted in the rear of the pilot house just aft of center control stand. The ship's navigation equipment includes radar, a recording fathometer and a radio direction finder. All in all it will be a much more efficient and economical ship to operate.
Then, in the March-April, 1949 issue, came this photo of a model for the new mine planter with a note:
Mine Planter-Of major importance to the modernized flotilla is the new 127-foot mine planter now under construction at New York, later to be launched and completed at Todd's Shipyard, Charleston, S. C. After some delays this prototype planter, which has been designated USAMP Sgt. Truman O. Olson, is being rushed to completion. Incorporating all possible features which will make for efficient operation in the mine field, and eliminating those features which caused the old planters to become general purpose ships, the 127-foot planter will be the first such ship designed for submarine mine work exclusively. One innovation which has great promise is the use of cydoidal propellers. This type of propulsion should make the new planter highly maneuverable.
There we have the solution to some minor mysteries that have seemed to surround two odd Navy vessels, YMP-2 and YMP-3. The YMP-1 was one of the Army Design 277 (Vessel, Passenger-Cargo, Diesel, Wood, 114') types and not particularly unusual. The other two had an air of mystery about origins with "captured German" being rumored and "without propellers or rudder" being strange. Now we know. Those "Voith-Schneider cyclodal propellers" that were " captured German units" and installed in the first ships "designed expressly for cyclodal propulsion to be built in this country" are the origins of those stories.
The Army's harbor defense role of this kind was over and the Navy's to be short lived. So these vessels designed for the Army's future that before operation became the Navy's closing days of harbor defense were indeed unique oddities. Tim Colton shows YMP-2 completed for the Navy at Todd Atlantic, Charleston, S.C. YMP-3 was apparently completed at Higgins, New Orleans though Colton's list shows no such vessel. One source has it built for the Mutual Defense Assistance Program in 1958. In any case it ended up in Turkey apparently without U.S. service. The image shown at NavSource for YMP-3 fits the Army 127 foot mine planter.