Wanted to make a quick comparison of these two AFV kits in case others want to build or convert them:
At first glance, most components shared, but some key differences between these two kits:
AFV #73512 (lower kit in picture) depicts the USS Dace (SS-247), a Gato Class submarine built at Electric Boat and later converted under the GUPPY Ib program, recommissioning in 1954 for eventual transfer to Italy's Marina Militaire in 1955, where she served until 1972 as Leonardo da Vinci (S-510).
Wikipedia notes the GUPPY 1b program was "an informal designation for a limited upgrade and modernization given to four boats for transfer to foreign navies. These boats had snorkels and were generally similar to the GUPPY IA, except that they were not equipped with the modern sonar, fire control systems, or ESM. The two Italian boats were of the thin-skinned Gato class."
USS Barb (became ITNS Enrico Tazzoli (S-511) Marina Militare)
USS Dace (became ITNS Leonardo da Vinci (S-510) Marina Militare)
USS Hawkbill (became HNLMS Zeeleeuw (S-803) Royal Netherlands Navy)
USS Icefish (became HNLMS Walrus (S-802) Royal Netherlands Navy)
AFV #73513 (upper kit in picture) depicts the USS Cutlass (SS-478), a Tench Class submarine built by Portsmouth Naval Yard and later convered under the GUPPY II program, with the conversion happening in 1948 at Philadelphia Naval Shipyard. Eventually decommissioned in 1973 (there's quite a gap in Wikipedia's history), Cutlass was sold to the Republic of China, where she was commissioned in the Republic of China Navy as ROCS Hai Shih ("Sea Lion"), SS-791. As of April 2012, Hai Shih was still in service - she is noted in the instruction's notes as the world's longest-serving diesel submarine.
Wikipedia notes that the GUPPY II program implemented from 1947 to 1951 "was generally similar to the GUPPY I, except for retention of both periscopes and introduction of the recently perfected snorkel. The addition of three new masts � snorkel induction, snorkel exhaust, and ESM mast � required more room in the upper portion of the sail. BuShips approved two different sail designs:
The "Electric Boat Sail" had a straight trailing edge, round windows, a wider top and a more rounded forward edge.
The "Portsmouth Sail" had a thinner top, curved trailing edge, square windows and a sharper lower forward edge. It was put on all boats that used the government plans for the conversion.
Some boats with a Portsmouth Sail had an SV radar and needed extra room to house the aerial, thus had a bulge at the sail top. Later modifications put the SS or SS2 radars on these and other boats that had a smaller aerial and had an indicator with interlocks, allowing the mast to be housed only with the aerial in certain angular positions. Also, some GUPPY II and GUPPY III boats had their sails extended higher above the waterline, the "Northern Sail", to raise the bridge, allowing it to be manned in more severe weather."
Other submarines receiving the Guppy II conversion (but not necessarily of the Tench Class modeled here) were:
Catfish (became ARA Sante Fe (S-21) Argentine Navy) (with a Falklands Conflict role)
Clamagore
Cobbler
Cochino
Corporal
Cubera
Diodon
Dogfish (Became Guanabara (S-10) Brazilian Navy)
Greenfish
Halfbeak
Tiru
Trumpetfish (Became Goi�s (S-15) Brazilian Navy)
Tusk (Became Hai Pao (SS-792) Republic of China Navy) Active in service
Cutlass (Became Hai Shih (SS-791) Republic of China Navy) Active in service
Amberjack (Became Cear� (S-14) Brazilian Navy)
Odax
Sirago
Pomodon
Remora
Volador
Sea Leopard (Became Bahia (S-12) Brazilian Navy)
Grampus (Became Rio Grande do Sul (S-11) Brazilian Navy)
Pickerel
Grenadier
For those interested in modeling any of the above other than the USS Tusk/ROC Hai Pao presented in this kit, you're going to have to check USS class type and GUPPY conversion sail type before beginning your builds to assure accuracy. It certainly is possible to switch out hulls and sails between these two kits and still fit parts. The AFV GUPPY ib kit features the "Portsmouth" sail; the AFV GUPPY II kit features the "Atlantic" sail.
So, to be specific about the differences in the two kits:
AFV #73513 (Guppy II)
Ex-Tench Class
Atlantic Sail
Larger sonar array
Anchor location on port side
No limber holes
Upper hull planking pattern and deck features distinctly different from AFV #73512
Decals for both USN and ROC boats
PE includes distinct railings for this class, running partial length of deck
AFV #73512 (Guppy Ib)
Ex-Balao Class
Portsmouth Sail
Small sonar array, located further aft
Anchor location on staboard side
Limber holes
Upper hull planking pattern and deck features distinctly different from AFV #73513
Decals only for Italian naval service
PE includes distinct railings for this class, running the full length of the deck, and handrails for the sail
Here's a comparison of the two sail types:
GUPPY Ib hull bow, with limber holes:
Guppy Ib stern:
Initial assembly (dry-fit sail), GUPPY II - note no limber holes:
