[Icelander]

I understand from what sources I can find that Royal Navy truck carriages for long guns in the late 18th century and early 19th century were about 20% of the weight of the gun.* This translates into just over 6 cwt to 13 cwt (716-1,456 lbs.) weight of naval truck carriages for guns ranging from a medium 12-lb to a short 42-lb. The sliding carriages used by carronades were about half the weight of the carronade**, except for the 68-lb carronade, which had a carriage weighing only 28% of the carronade itself.

Field artillery carriages were far heavier, proportionally. Even the famously light 'Grasshopper' 3-lb piece required a carriage of around 300 lbs., which is around 150% of the weight of the cannon itself. Field artillery 6-lb cannon usually required a carriage weighing around 900-1,200 lbs., which is from 101% to 180% of the weight of the piece itself. Heavier field artillery required carriages of 0-5-1 ton in weight, usually weighing only slightly more to slightly less than the cannons themselves (72% to 125%).*** Though not universal, there is a fairly obvious trend toward lighter carriages from the 1770s to 1815 and the carriages that were only 100% or less of gun weight nearly all date to the latter part of the Napoleonic wars.

Obviously, these are all solidly TL5 carriages, made after Gribeauval's artillery design revolution in France during the 1760s. Does anyone have a good idea of what advancements in design or manufacturing are required before a TL4 industrial base can build TL5 carriages?

Also, what would be a fair Cost for these carriages, if someone were making them with TL4 technology?****

It's obvious that they would be much more expensive than the TL4 carriages listed in Low-Tech, but how much more expensive? Three times more expensive? Four times? Five times? Ten times? Twenty times?

*I would give limited credence to the bare statement in a text that this was so, but I was able to find sources for the actual weights for the carriages for the 12-lb, 24-lb, 32-lb and 42-lb aboard the HMS Victory and they are all 20% or less of the gun weight.
**53% for the 12-lb, 45% for the 18-lb, 24-lb and 32-lb.
***Discussion of field guns and their carriages, including some weight figures, can usually be found in works on Napoleon's and Wellington's campaigns, as well as in treatments on the American Revolutionary War. Pieces from these wars, on replica carriages, can often be seen in museums.
****No factories, hand-crafting all metal screws, axles and such, etc.