Page viii contents 



Page 



62. Physics of sound 557 



621. Physical laws of sound. 622. Propagation in an ideal water medium. 

 623. Propagation in a heterogeneous water medium. 



63. Velocity of sound 573 



631. Practical use of velocity of sound. 632. Temperature of sea water. 

 633. Salinity of sea water. 634. Records and computations. 635. Determina- 

 tion of velocity. 636. Methods of applying velocity data. 



64. R.A.R. stations 595 



641. Shore R.A.R. stations. 642. Ship R.A.R. stations. 643. Sono-radio buoy sta- 

 tions. 644. Radio frequencies and power. 



65. Sono-radio buoys 601 



651. Vincent sono-radio buoy. 652. East Coast sono-radio buoy. 653. Com- 

 parison of East Coast and Vincent sono-radio buoys. 654. Adjustment of a 

 sono-radio buoy. 655. Operating difficulties. 656. Hydrophones. 



66. R.A.R. bombs and explosives 618 



661. Types of bombs. 662. Bomb containers. 663. Construction of bombs. 

 664. Deep-sea bomb. 665. Storage of bombs. 666. Trinitrotoluene(TNT). 

 667. Detonators. 668. Fuse. 669. Precautions in handling explosives. 



67. Ship personnel and equipment 626 



671. Personnel organization. 672. Ship equipment for Radio Acoustic Ranging. 

 673. The chronograph. 674. Communication system. 



68. R.A.R. operations 636 



681. R.A.R. positions. 682. Plotting R.A.R. positions. 683. R.A.R. sounding lines. 

 684. Bombing operations. 685. Chronograph tapes. 



Chapter 7.— THE SMOOTH SHEET 



71. The Sheet 657 



711. Smooth-sheet paper. 712. Smooth-sheet size. 713. Auxiliary plotting sheets. 

 714. Tracing mediums. 



72. Drafting and lettering 663 



721. Character of the drafting. 722. Orientation of smooth sheet. 723. Lettering. 

 724. Selection of pencils. 725. Selection of pen points. 726. Inks. 727. Erasing 

 and cleaning. 



73. Preparation of the smooth sheet 666 



731. Protection of smooth sheet. 732. The projection. 733. Hydrographic sheets 

 from air photographic surveys. 734. Projections for R.A.R. sheets. 735. Plotting 

 large-scale offshore surveys. 736. Changing datum of survey sheet. 737. Projec- 

 tion constructed after survey. 



74. Plotting the control ■ 683 



741. Plotting the shore control. 742. Plotting the floating control. 743. Station 

 symbols. 744. Station names. 745. Verification of the control. 746. Projection 

 and control data. 



75. Transfer of the topography 691 



751. Omission of topography. 752. The shoreline. 753. Revisions by hydrographic 

 party. 754. The low-water line. 755. Offshore detail. 756. Methods of transfer. 

 757. Verification of transfer. 



76. Plotting the positions 697 



761. Smooth-sheet covers. 762. Protracting three-point fix positions. 763. Plotting 

 R.A.R. positions. 764. Plotting astronomic positions. 765. Plotting the dead 

 reckoning. 766. Detached positions. 767. Use of boat sheet in smooth plotting. 

 768. Identification of positions. 769. Plotting supplemental data. 



77. Soundings and depth curves 714 



771. Depth units. 772. Plotting the soundings. 773. Penciling the soundings. 

 774. Errors in soundings and positions. 775. Congested areas. 776. Depth curves. 

 777. Inspection of plotting. 



