The Dog Boat is presented as a favorite design because its motor-torpedo and motor-gun configurations could be optimized for different missions. With 228 of 229 planned boats completed, the type also embodied the scale of British coastal-force production. Its broad beam and low machinery helped create a stable platform, while six-pounders, 20 mm guns, machine guns, depth charges, smoke gear, and improvised additions could make it exceptionally heavily armed. The British accepted a lower maximum speed than the fastest German or Italian boats in exchange for firepower, stability, endurance, and rough-water capability. A range of about 2,000 nautical miles at 11 knots allowed the type to remain useful far beyond a short dash from harbour, and captured examples also entered Kriegsmarine service. The Royal Navy used its numerical advantage by mixing Dog Boats with Vospers or other Fairmiles, often sending eight to ten craft against smaller German groups rather than seeking even small-craft duels.
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Fairmile D "Dog Boats": guns, stability, and endurance
The Fairmile D combined a broad, stable hull with long endurance and heavy, adaptable armament, making it a particularly capable British answer to enemy coastal forces.