Finnish Kilo submarine feasibility

How useful would Soviet Project 877-style submarines have been for Finland if delivered as debt payments and fitted with Western technology?

The hulls could be useful, especially with missile capability, but Westernizing submarines is risky and Finland would need to rebuild submarine personnel from scratch.

Kilo-family hulls are judged a useful starting point, although the variant depends on when the hypothetical transfer occurs. The possibilities range from the original Project 877 family and EKM boats to later Project 636 designs. Modifying a submarine pressure hull can introduce weak points, making Western equipment integration more hazardous than a comparable surface-ship refit. Finland would also need to establish a submarine cadre after operating without one through the Cold War. A missile-capable version is preferred for the strategic depth and deterrence it could provide.