I realize it is impossible to accurately compare the cost of something from many centuries ago to today, but I'm just trying to get a general idea of how much a ship was worth. I would like to know the relative cost of a "merchantman" a "war galley" and a "carrack". It doesn't have to be a specific number if that's not possible. Would losing a few merchant ships have ruined the economy of a small country? Could a sailor ever hope to save up enough to buy his own ship? Was a trading ship generally worth more or less than the cargo it was hauling? Were warships somewhat expendable or did monarchs/governments have to protect them? Again, just a general idea of the cost is all I'm looking for.
I also realize that ships could vary quite a bit within the categories above but I didn't want to get so specific that it limited the potential sources. I can get more specific in my question if it is required in order to provide an answer. Thank you.
I am not aware of many sources for the costs of medieval ships. Perhaps someone else will contribute with more.
Here are some data. They all come from the century after the one you are interested in unfortunately.
The English warship Mary Rose, built in 1510, was a huge ship for her era. She was about 1500 tons and carried a number of cannon. She had a crew of about 500 men. Ships of her type cost about 1,650 pounds to build.
http://www.thepirateking.com/ships/brief_history_wind_powered_ships.htm
We have a record of a 52 foot long fishing vessel with 16.5 foot beam built in 1609 in Rye for 100 pounds.
The town of Rye also built a 25 ton “pinnace” in 1588 for service against the Spanish for 64 pounds.
http://www.gresham.ac.uk/lectures-and-events/elizabethan-merchant-ships-and-shipbuilding
Most English ships in this period were small.
In 1582, a fairly good survey of English ships counted:
10-80 tons – 1,204 ships
80-100 tons – 73 ships
More than 100 tons – 178 ships
(The English government subsidized the building of ships greater than 100 tons since the 15th century, as they were thought to be useful for the defense of the realm.)
Between 1560 and 1610, the government paid this subsidy towards the construction of 510 vessels. 126 of these ships were built between 1560 and 1588, while 384 were built between 1589 and 1610, indicating that the number of large ships being built was increasing.
For a valuation of ships seized for piracy, as prizes of war, for smuggling, the records of the English High Court of Admiralty are useful indicators of the values of existing ships. Between 1579 and 1590, we have records of 119 ships coming before this court.
The ages of these ships, where listed, ranged from 1 year to 50 years old, and averaged about 15 years.
For 79 of these ships we can compare the value appraised by the court against the tonnage.
43 ships were valued at less than 1 pound per ton
21 ships were valued at between 1 pound and 1.5 pounds per ton
14 ships were valued between 1.5 and 3.5 pounds per ton
1 ship was valued at 6.8 pounds per ton
The tonnages ranged from 20 to 200 tons. About half these ships had weapons. Age and condition of the ship and the number of cannon (these were small – most firing 1.5 to 4 lb shot, the largest firing 6 lb shot, when royal ships generally mounted cannon firing 9lb – 18lb shot) seems to have had considerable impact on the value.
Merchant ships generally seem to have been worth a lot less than their cargoes. An old 35 ton Dunkirk flyboat seized in 1588 was appraised to be worth 15 pounds, but its cargo, mostly cloth, was appraised at 827 pounds.
It looks to me like ships generally cost between 1 pound and 3 pounds per ton (less if old and decrepit). There may have been some economies of scale (larger ships costing less per ton) but these larger ships may have had more cannon, which were expensive.