Thailand, or at least many senior naval officers, wants to buy six German U-206 submarines for $43 million each. That sounds like a bargain, but there are several catches. About a year ago, Germany decommissioned these six U-206A coastal submarines. The 450 ton boats each had a crew of 22 and were only 48.6 meters/151 feet long, and 4.6 meters/14.25 feet wide. They were armed with eight 21 inch/533mm torpedo tubes. They could stay at sea for about five weeks at a time. Germany built 18 of these boats in the 1970s, then refurbished twelve of them in the early 1990s. Six of those have already been retired, and the remaining six were supposed to remain in service until 2016. By then, Germany expected to have two new U-212A subs in service. These two new boats are still on schedule. The six U-206As were taken out of service because of a shortage of money and naval threats. Then there's the unexpectedly high costs of maintaining troops in Afghanistan. The money had to come from somewhere.
The German U-206A sailors were retrained and transferred to the remaining U-212A subs. These are much larger (1,450 ton) boats, but only require 27 sailors to operate. The U-206A sailors will allow two crews to be formed for each U-212A boat, a practice being adopted by more nations, to keep subs at sea more, and maintain the morale of crews. Submarine sailors are difficult to recruit (very high standards) and retain (all that time at sea is uncomfortable, and hard on family life.)
The Thai government is not enthusiastic about acquiring these used, but well maintained, German subs. The Thai navy has a hard time making the case that there is any current, or potential, naval foe that the subs could be used against.