The Napier Deltic Marine Engine

THE NAPIER DELTIC MARINE ENGINE

E. E. Chatterton, B.Sc.(Eng.), M .I.M ech.E ., F.R .A e.S.,* and D. D. P. Fuller**

Introduction

The recent amendment to the Merchant Shipping Act has two principal effects. In the first place, it gives scope for smaller main propelling machinery installations disposed so as to occupy the minimum possible space consistent with the efficient and safe operation of a vessel. In the second place, the amendment offers incentive to marine engine designers to develop lighter and more compact units which will permit further saving of space than is possible by merely changing the position and design of engine rooms. In this paper proposals are submitted designed to take full advantage of the new regulations by the application of the Napier Deltic marine engine, which is now being manufactured for the Royal Navy and for the navies of several foreign powers. The recent amendment to the Act has given rise to still more active consideration of the application of the Deltic engine to merchant ships, and the invitation from your Papers and Transactions Committee to embody some of the conclusions in this paper is welcomed.

As always, consideration of a question of this nature must be based on the requirements of the shipowner, namely that a cargo should be transported at the required speed at the lowest possible cost per ton. The introduction of propulsion machinery of advanced design, thus saving space and weight, offers an opportunity to reduce substantially the cost of transporting cargo at a given speed, and in considering any proposals it is essential that full consideration should be given to this aspect, which may be broadly subdivided as follows : —

1. A reduction in the capital cost of the machinery.

2. A reduction in the capital cost of the hull in relation to cargo capacity.

3. A reduction in the cost of the hull due to the lighter machinery.

4. A reduction in power (or fuel consumption) in relation to cargo capacity.

The relative importance of each of these factors on operating cost will, of course, depend on the operating schedule of the ship, but in general the most important factors will be those which affect the capital cost of the vessel. It is submitted that by the use of multi-engine installations using compact engines of modern design, advantages can be shown on each of the foregoing counts. The detailed features of construction referred to in the following proposals have already been widely published and a paper devoted to the operation of Deltic engines will be presented to the Institute by Mr. Chatterton during next session. For ready reference, however, those features of design and performance which are relevant to the application of the engine to merchant ships are repeated here.

The 18-cylinder Deltic engine comprises six triangular banks. Each bank is in the form of an equilateral triangle with a main crankshaft journal at each apex, as illustrated in

* Chief Engineer (Piston Engine Division), D. Napier and Sons, Ltd.

** Manager of Deltic Engine Sales and Contracts, D. Napier and Sons, Ltd.