No. of Recommendations: 7
Though they could use their subs to harass (directly) sea traffic. Diesels are very quiet, and difficult to detect.
Diesels are very noisy and can only run when the sub is on the surface, not a great plan in a relatively narrow sea or isthmus. Diesel subs run on batteries when underwater, and only have enough juice for a couple days, although newer ones with fuel cells can triple that time or more. Running on electric makes them quieter, but not at all quiet. They can still be easily detected by sonobuoys or other means. They are still limited by motor noise and cavitation of the water passing the propellers.
Recharging the batteries takes several hours so it is not inconsequential for a sub to sit on the surface to do so.
