The Wind of Luck team has posted a short update about the game's progress towards release. The plan is to release WoL in two parts, first the WoL Arena followed by the rest of the project pending funding sources.
As for WoL:Arena - Ships will be partially upgradeable, with equipment and crew, and there will be some progression from smallest boats to 1-rate ships. players will earn fame and money in each battle and spend it to research and buy new ships, cannons and equipment. I.e. in "Asian" tree there will be like 9 tiers of ships starting from Hokulea and finishing in some really huge vessels like legendary Treasure Ship of Zheng He fleet. Yes, it means that we will need to completely rebalance ships for WoL: Arena but it seems like the only way to make the game finally live.
Read the full post on the Wind of Luck site.