How & Why during WWII MTBs became MGBs: European & Mediterranean Theatre

European and Mediterranean coastal warfare shifted from torpedo attacks on major ships toward armed fights between fast coastal craft.

Only if the navy had a role that justified a new intermediate type; for Britain, destroyers and smaller coastal vessels often covered the likely tasks more economically.

The World War I background shows why small torpedo craft appealed despite limited headline successes: they were cheap, numerous, and could carry weapons dangerous to much larger ships.

They could travel aboard larger ships in complete or kit form, but some carried extra fuel and self-deployed over long distances, including passages toward Malta.

Fast boats began as torpedo threats to larger ships, but European waters pushed them into fighting one another and made smaller, faster-firing weapons essential.

Late nineteenth- and early twentieth-century capital ships sometimes carried small torpedo boats, giving a distant battleship its own deployable fast-attack craft.

The most useful weapon against lightly built fast craft was often an anti-aircraft gun rather than a cruiser or destroyer’s heavier main battery.

Italian MAS development linked the First World War Adriatic to the Second World War, when stripped-down examples operated on Lake Ladoga during the siege of Leningrad.

They had limited protective armour around vital crew positions, but too much would undermine speed; British heavier armament chiefly answered the need to kill fast boats quickly.

Italian MAS boats suited the Mediterranean as extremely fast torpedo craft, but their strengths depended on striking quickly and escaping rather than sustained combat.

German Räumboote were primarily minesweepers and support craft, yet their wide service record means that not every wartime British report of an “E-boat” meant a Schnellboot.

The R-boat family grew from small mine-warfare vessels into larger, adaptable craft that could carry torpedoes and other armament when required.

The Schnellboot’s refined lines and diesel development made it a formidable torpedo attacker, but the same design choices constrained its gun platform and rough-water performance.

The early Schnellboot line served as an export and technology-transfer story as well as a German design programme, beginning with sales to Nationalist Spain and ending in several Allied navies.

The modestly named Harbour Defence Motor Launch was a long-range, wooden anti-submarine craft whose practical service reached far beyond a literal harbour.

It displaced about 54 tons fully loaded, with each of its two engines producing 152 brake horsepower.

Vosper’s 70-foot boats show how disrupted Dutch procurement, several hull variants, varied engines, and mixed torpedo-and-gun fits produced a widely adopted high-powered MTB design.

Full speed was intended for relatively calm water, around sea states two or three, though crews sometimes pushed boats hard in rougher conditions at considerable strain.

No official record is cited; an unofficial account says Abdiel-class minelayers overtook U.S. carrier groups already running at full speed.

The Fairmile A and B show a different coastal-force priority: seaworthier, broadly produced subchasers and escorts rather than pure high-speed torpedo attackers.

It depends on the test and period; some early trials used brake horsepower, while British practice increasingly standardized figures as shaft horsepower for comparison.

The roughly 650 Fairmile Bs demonstrate how Allied production scale and standardized upgrades could matter more than the performance of any single fast-boat design.

The Royal Navy's quick-firing label described period loading and handling standards, not an automatic weapon in the modern sense.

The notes checked during the talk list construction in New Zealand, Australia, and South Africa, but no Indian build.

The 1941 Fairmile C marks an explicit move into the motor-gun-boat role, with pom-poms, machine guns, Oerlikons, and depth charges replacing the earlier subchaser emphasis.

Italy’s CRDA 60-ton MS boats reflected the realization that the very fast MAS design sacrificed too much ability to operate when Mediterranean conditions worsened.

They combined junior officers with experienced chiefs, technical ratings for weapons and sensors, and crews focused mainly on gunnery and machinery.

Indirectly: Italy adapted captured Yugoslav boats derived from early Schnellboot work into a more seaworthy alternative to the MAS.

Vosper’s 73-foot boats could combine high speed and torpedoes with a six-pounder gun, making them dangerous to enemy coastal craft as well as larger targets.

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.

Not generally; its broad beam and low machinery kept the centre of gravity low enough to support the heavy armament.

They seldom met on equal terms because the Royal Navy often concentrated larger mixed flotillas against smaller German groups.

A late discussion challenges equipment-only comparisons by pairing German armoured success in France with British tank performance in North Africa and the British Army's high degree of motorization in 1939.

The comparison of France in 1940 with ABDA Command makes command structure, doctrine, and communications part of the explanation for early Allied operational problems.

Reports of Tommy guns, grenades, and other unofficial weapons show why published coastal-craft armament lists can only approximate what crews actually took into close-range action.

The closing argument ties the MGB’s heavy armament to convoy defence: British forces increasingly used intelligence, radar, and ambush tactics to meet raiding boats before they reached their targets.

Hedgehog was not identified on British MTBs, while Mousetrap was fitted to American-operated subchasers of Fairmile ancestry rather than British boats.

The deadly Schnellboot attack during pre-D-Day Exercise Tiger receives brief treatment here because it lies beyond the main focus of this design survey.

A radar-plotting example shows how operational descriptions can imply that a ship used equipment absent from its official fit, leaving jury-rigging or unofficial procurement as plausible explanations.