JANUARY 27, 2021
By J.B. Hadler (Fellow), E.N. Hubble, R.G. Allen and D.L. Blount
Our team has the pleasure of supporting many clients in the definition phase of their projects. In these early on, low maturity efforts, we have discovered the need to be able to produce relatively accurate design/product information in a short amount of time with little known information. This necessity leads us to follow the Pareto Principle in early stage design, where 20% of the work will lead the team to 80% of the results. One paper we have found extremely helpful in these efforts is the Planing Hull Feasibility Model, which we fondly refer to as PHFM. PHFM was an effort by the U.S. Navy to develop regression equations based on existing US Navy planing craft to aid designers in there feasibility studies. Over the years we have used the techniques and equations extensively and updated them as necessary to reflect modern technology. It’s a great tool in our toolkit!
This paper outlines the development of a feasibility model which can be used to assist in the design of planing hulls. The concept of the model is to calculate the weight, volume and vertical centre of gravity of the major ship components, including the variable loads, for a planing ship or fixed displacement and enclosed volume, with the remainder of the weight and volume available for the payload.
The data base for the model includes small patrol craft, hydrofoils, destroyers DD, and destroyer escorts DE, so that wide range of planing ship sizes can be considered. The hull structural design concept is based upon a rational design procedure which takes into account sea loads as well as the effect of changing hull proportions, i.e., length, beam, and depth.
Results of studies done on a typical hard-chine planing ship with mission and basic characteristics Similar to the US Navy’s PG89 Class show the value of the feasibility model in improving the payload carrying ability by optimizing the ship proportions. The effect of different types of hull material and construction upon the overall ship size, as well as the effect of reducing the weights of the reduction gears, are shown from feasibility model studies.
In case you would like to receive the full paper, or discuss about this subject, please contact Jeffrey Bowles.
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