Accession Number:

ADA030218

Title:

Theoretical Determination of Porpoising Instability of High-Speed Planing Boats

Descriptive Note:

Corporate Author:

DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD

Personal Author(s):

Report Date:

1976-04-01

Pagination or Media Count:

73.0

Abstract:

A theoretical method is derived for predicting trim angle and speed coefficient at the inception of porpoising of prismatic planing hulls. Although equations are derived for the surge, pitch, and heave degrees of freedom, it is seen that the effect of surge is small at ordinary operating trim angles. Comparisons of theoretical predictions with existing experimental data on coupled pitch and heave porpoising show reasonably good agreement for a wide range of speed coefficients, load coefficients, and deadrise angles. The theory may also be used for estimating the natural frequencies and damping characteristics of prismatic hulls in the stable, high-speed planing range.

Subject Categories:

  • Marine Engineering
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE