In early 1930s Polish Navy was planning to build a training ship for Naval Academy, but government was not willing to spend money on ships that were not really combat capable. As result, ORP Gryf was designed, officially minelayer/pride of the navy/trainig ship hybrid. It's proposed wartime mission was to lay large minefield in Gulf of Finland (as when she was designed most probable enemy was Soviet Union) to prevent Soviet navy from entering Baltic. This in general sounds a bit fishy as operation such as this called for sth like British Abdiel-class minelayers - so fast that they could run there, lay mines and return in a single night. Real ORP Gryf though was painfully slow (20kts) while very economical, as she was powered by diesel engine. As result, if such mining operation was attempted, the ship would be most probably caught at daybreak by Soviet air force and sunk. And the minefield, even 300 mines, would not be enough to close Gulf of Finland, not to mention that completely unprotected minefield could be easily removed.
So, in reality, it was most probably primarily training ship that the navy needed (recent studies show that just after her arrival under deck mine handling rooms were adapted for berthing, cutting mine capacity by more then a half). Supposed large mining capacity and powerful main battery (6x120m) as well as planned wartime use were probably smoke and mirrors for politicians to accept funding.
What if in a different world finally decision was reached to build ship, that could fulfill all roles Gryf was to serve - capable cruiser and minelayer but also training ship for Naval School during the peace time. Was Poland able to finance such project? It is questionable. But maybe? After all, It is not a battleship level of expensive
Ship project was based on the hull of heavy cruiser Algerie and was built in France, just in some more reliable shipyard than usual Polish pick Chantiers et Ateliers Augustin Normand in Le Havre.
To make space for mining deck, turret Y was deleted and deck up to aft superstructure was flattened and equipped with mine rails leading to 2 ramps on stern.
Remaining turrets were changed from twin 203mm to triple 152mm to avoid any treaty considerations. Those turrets were ordered in Swedish Bofors, using long barreled (L/55) guns ordered before for coastal battery on Hel peninsula (Bateria im. H.Laskowskiego) and Swedish cruiser Gotland.
I assume the ship would use more modern machinery then Algerie, giving additional about 1-1,5 kts for a max speed of 32,5kts. In and attempt to make the ship at least a bit similar to Grom class DDs original funnel was replaced with raked and streamlined one.
Soon after arrival in Poland in 1938 additional superstructure was added on the after deck, occupying most of the supposed mine deck. It was designed as berthing space for 300 cadets, and on the deck various guns were fitted for training purposes, including singe and double 120mm turrets as used on Grom class destroyers, 75mm guns used on smaller ships, Bofors 40mm AA and 13,2mm Hotchkiss AAMG.
Both this superstructure and the large "hotel" part (housing lecture halls and additional accommodation) were constructed in such way as to allow quick removal in case of imminent war.
AA battery would definitely have multiple 40mm Bofors guns - 4x2 on the after superstructure, 4x2 on the front superstructure and 1x2 on the training deck. 1-2 75mm on the training deck would also be AA capable. All Polish ships had twin 13,2mm AAMGs so Gryf would definitely have them as well. On the other hand, I do not plan to add heavy AA battery. A questionable choice, as original ship had them, but for example Dutch cruisers lacked it as well. Plus Poland lacked suitable gun so it would be another atypical ammo in the supply chain.
I am yet undecided if the ship should have catapult and planes. Probably yes.
Before leaving for Britain in August 1939 ship would land both 120mm turrets, to be used as coastal defense. "Academy" superstructures would be removed after arrival in UK and British 4in AA guns in twin turrets would be fitted amidships and maybe on the mine deck, turning her into solid AA ship, especially after those were integrated with proper AA FC later in the war.
Ship so far, showing her in service just before the war. Obviously a lot needs to be done, but what do you think so far?