From the mods page, mega mods for 1.4. I assume the links still work. Basically you have 3 options, but I would use TMO with RSRD.
Stock 1.4 game with Run Silent Run Deep - The Campaign:
RSRDC_V350_for_V14 --D/L Link:
http://silenthunter.filefront.com/fi..._for_14;106055
RSRDC_V350_Patch1 --D/L Link:
http://silenthunter.filefront.com/fi...or_v350;106057
RSRDC_SH4V14_CTDFIX --D/L Link:
http://silenthunter.filefront.com/fi...top_Fix;106051
Trigger Maru, Trigger Maru Overhauled w/ RSRDC (optional):
REL_TriggerMaru_Overhaul --D/L Link:
http://www.megaupload.com/?d=OKA4IYO9
-OR-
1_TMaru_Trigger_Maru_1.7.6 --D/L Link:
http://silenthunter.filefront.com/fi...aru_176;106067
RSRDC_TMOv14_V370 --D/L Link:
http://silenthunter.filefront.com/fi...ampaign;106047
RSRDC_V370_Patch1 --D/L Link:
http://silenthunter.filefront.com/fi...or_v370;106049
RSRDC_SH4V14_CTDFIX --D/L Link:
http://silenthunter.filefront.com/fi...top_Fix;106051
Note that TM-1.7.6 or the original TMO (for 1.4) will work with RSRDC V370.
Real Fleet Boat for v1.4 w/ RSRDC (optional):
RFB_v1-4_031408 --D/L Link:
http://www.megaupload.com/?d=4TQ0IULI
RFB_V1-4_TorpedoFix_081108 --D/L Link:
http://silenthunter.filefront.com/fi...x_Patch;106053
RSRDC_RFBv14_V390 --D/L Link:
http://silenthunter.filefront.com/fi...at_V390;106061
RSRDC_v390_Patch2 --D/L Link:
http://silenthunter.filefront.com/fi...Patch_2;106065
RSRDC_SH4V14_CTDFIX --D/L Link:
http://silenthunter.filefront.com/fi...top_Fix;106051
-- note there is no "patch 1" for RSRDC v390. Patch 2 contains all the needed fixes.
The above files are the last releases for 1.4. They will not work with 1.5.
FooFighter's Sub Skins:
website link (download the skins from there):
http://www.oldsmobile1958.com/silenthunter/
ROW, PE, or Environment should be installed last. Rumor has it PE4 or Environment will work with 1.4. I'm currently running PE4 with TMO and RSRDC V370.