Dennis F. Jones
Defence Res. Establishment Atlantic, P.O. Box 1012, Dartmouth, NS B2Y 3Z7, Canada
The class I barrel-stave flextensional projector is a lightweight and compact underwater sound source that is well-suited to low-frequency sonar and oceanographic applications. By modifying a few of the parts used in the class I projector, a high-power class II or broadband class III barrel-stave projector can be constructed, which is testimony to the versatility of the basic barrel-stave design. These projectors require gaps, between adjacent staves, that are sufficiently wide for free-stave vibration at the operating drive levels and water depths. Gap widths of about 1 mm are typical. A rubber boot is stretched over the projector to inhibit the ingress of seawater through the gaps. However, since the gap widths and boot wall thicknesses are similar, the boots can be forced into the gaps by hydrostatic pressure, causing significant variations in the projector performance parameters with water depth [D. F. Jones and M. B. Moffett, J. Acoust. Soc. Am. 93, 2305(A) (1993)]. To minimize these variations, a new rubber boot with reinforcements in the vicinity of the gaps has been fabricated and tested on a class II barrel-stave projector. Measured results showing performance stability with depth are presented.