20 years loan at 4.5% interest rate from SDE Banking Services.
Seriously, this should probably be in general tips&tactics section, not in the UK national subforum.
-Play games (blitz lesser xp means you normally collect more creds/points with them)
-avoid remodeling. You never get those fees back.
-Sell some sailors with good base. For best result, level them to 12, and wait to class them that you have an interested buyers. Make sure you include the points needed to class them in the cost of the transaction. Neut trade used to be doable, but they nuked it to promote elites sales.
-Easy way : Buy a PCV and sell it to harbor.
Once you have your first CV, they are credit-making machines, and cred stop being an issue.