Type XXIs had much better facilities than previous classes, with a freezer for foodstuffs and minor conveniences for the crew such as a shower and wash basin. They were much quieter, and enjoyed a hydraulic torpedo reload system that allowed all six torpedo tubes to be reloaded faster than a Type VIIC could reload a single tube. Improvements in battery design yielded a storage capacity roughly three times that of a Type VIIC, giving these boats enormous underwater range. They could travel submerged at about five knots for two or three days before recharging the batteries, which took less than five hours on the snorkel.
Between 1943 and 1945, 118 boats of this type were built by Blohm and Voss of Hamburg, AG Weser of Bremen, and F.Schichau of Danzig.
U-2501 - U-2502 - U-2503 - U-2504 - U-2505 - U-2506 - U-2507 - U-2508 - U-2509 - U-2510 - U-2511 - U-2512 - U-2513 - U-2514 - U-2515 - U-2516 - U-2517 - U-2518 - U-2519 - U-2520 - U-2521 - U-2522 - U-2523 - U-2524 - U-2525 - U-2526 - U-2527 - U-2528 - U-2529 - U-2530 - U-2531 - U-2533 - U-2534 - U-2535 - U-2536 - U-2538 - U-2539 - U-2540 - U-2541 - U-2542 - U-2543 - U-2544 - U-2545 - U-2546 - U-2548 - U-2551 - U-2552 - U-3001 - U-3002 - U-3003 - U-3004 - U-3005 - U-3006 - U-3007 - U-3008 - U-3009 - U-3010 - U-3011 - U-3012 - U-3013 - U-3014 - U-3015 - U-3016 - U-3017 - U-3018 - U-3019 - U-3020 - U-3021 - U-3022 - U-3023 - U-3024 - U-3025 - U-3026 - U-3027 - U-3028 - U-3029 - U-3030 - U-3031 - U-3032 - U-3033 - U-3034 - U-3035 - U-3037 - U-3038 - U-3039 - U-3040 - U-3041 - U-3044 - U-3501 - U-3502 - U-3503 - U-3504 - U-3505 - U-3506 - U-3507 - U-3508 - U-3509 - U-3510 - U-3511 - U-3512 - U-3513 - U-3514 - U-3515 - U-3516 - U-3517 - U-3518 - U-3519 - U-3520 - U-3521 - U-3522 - U-3523 - U-3524 - U-3525 - U-3526 - U-3527 - U-3528 - U-3529 - U-3530