This points to the problems of lumping different classes of boats (small craft ) together.
Most of the boats in the 2nd MTB Flotilla were the early 60ft boats powered by a trio of Napier Lions of 550hp each.
There were two purchased boats, 55ft Thornycroft that were about 2/3rds the tonnage, that had been built for the Chinese.
These 55 footers were small boats with the crew not sleeping aboard.
The more common 72ft boats wound up with 3 Packards of 1200hp once supply shortages had been over come.
The Big Fairmile boats Started with the Type A (12 built) with three 600hp American Hall-Scott engines. These were 110ft boats of 57 tons light. These were hard chine boats. And held 1200 imp gal of fuel (not enough)
The mass produced Type B round chine boats used two 600hp Hall-Scotts because they couldn't get enough engines. Weight went to 67 tons. Later to 85 tons with increase armament and equipment. Fuel went to 2305 gal. Speed dropped to 20kts at best and 17.5kts max continuous for the early light boats.
Endurance was 600 Nautical miles at max speed and 1500 Nautical miles at 12kts.
It may have been these type of "boat" that did most of the long range voyages.
The Hall-Scotts were 2181(?) cu in engines that were close to 4000lbs with clutch and gear box (forward and reverse).
The 24 Fairmile C motor gun boats used a Type A hull with a strengthened deck and three supercharged Hall-Scotts of 850-900hp engines and could hit 26-27kts. Weight was 72 tons to start. More guns and equipment were added.
The Hall-Scotts were fairly rugged engines compared to the lighter/higher powered Packard V-2500 engines.
The later Fairmile D boats modified the hull a bit and used four Packard engines to drive the 90-118ton boats at 29-30kts (for the lighter boats).
Going back to the 70-72ft boats at the beginning of the war the high speed boats were powered by three Isotta-Fraschini engines of 1100-1150hp each which gave about 40-42kts in the early boats, but when Italy joined the war supplies were cut off and some boats were built with only two engines (?), a slow boat being better than no boat. There was period when they stuck three 600hp Hall-Scotts in the boats but that dropped the top speed to well under 30kts. Packard then supplied the V-2500 engines (not Merlins).
MTB/MGBs worked with a number of bases. They are short ranged boats, at least the small fast ones.
If you want fast (over 30kts) you are very limited on available engines or very, very limited on the size of the boats, Even 300-450hp light weight marine engines are not common in 1930s.
The 105ft MMS
was a rather different beast. A single diesel of up to 500hp in a 240-255 tons 'boat' that could hit 11-12kts.
Sticking a pair of 18in TT on board needs a strange combination of optimism and desperation. ( I don't think it was ever done).
But boatyards that can build such craft successfully may not be able to build 30+kt torpedo boats (at least and have them last very long).
There were some yards that could do it but most Far Eastern navies in the late 30s just bought a few boats from European makers (often British) although the Philippines managed to build a few.
Most of these were slightly updated/lengthened versions of the WW I 55ft Thornycraft boats that used a single step hydroplane hull to help with high speed. But this type of hull only worked in fairly calm waters which is why most of the British and American boats used V hulls.
The single step hydroplane was also rather sensitive to where the weight was.
