A Twilight of Empires

Converting MSP into Ship Units

Instead, use this:

At any point during the turn MSP on a trade route may be turned into transport units, i.e. HT, T, or XT as available.   MSP are converted to such units of equal cargo value, at least half of which must be of the highest cargo value.   The cost in gp is equal to the cost of the unit into which they are converted.

Regardless of when MSP are nationalized they will be removed from trade for the entire turn, and thereafter.   The militarized ships are to appear at the Base Port of the Route from which they were converted.   Please note that attempts to "game" the system in order to extract gp or nfp will be nullified.

Example

The ever-industrious Frisian king, Aethelwoof, realizes that he needs to transport his new army of horse archers across the sea.   Merchant shipping is his only hope, and so he approaches the bourgouisie with a command to turn over their ships in return for a nominal fee. If 40 MSP are to be converted, this will give 40 cargo value worth of hulls.   The Frisians had recently discovered how to build full-sized transports (T units) at 4gp/3nfp each, carrying 3 cargo per unit.   At least 20 MSP must convert to these, so we have (7 units) × (3 cargo/unit) = 21 MSP, costing (7 units) × (4 gp/unit) = 28gp.   This leaves 19 MSP as XT units at 2 cargo (3gp/2nfp) each.   Dropping fractions as usual, 9 units are available, costing 27gp.   In the end, 40 MSP become 7T,9XT with an out-of-pocket cost of 55gp, not counting the lost trade income. Overwhelmed by numbers in the merchants' contracts, a foe he could subdue with neither sword nor axe, Aethelwoof took to his bed.

Other combinations of unit type and number would give different results in the example above.   As they say, your mileage may vary.