Scharnhorst vs Alaska

[SteveSmith]

Scharnhorsts were very definitely battlecruiser since, while they were armored like battleships, they lacked the armament to harm battleships.

German and British battlecruisers had specific design attributes that separated them from battleships. One such attribute is that German battleships had three shafts and battlecruisers had four. Scharnhorst had three. The Germans always considered it a battleship.

[Thorsten Wahl]

German and British battlecruisers had specific design attributes that separated them from battleships. One such attribute is that German battleships had three shafts and battlecruisers had four. Scharnhorst had three. The Germans always considered it a battleship.

The Scharnhorsts were constructed with the Dunkerque class in mind. During the construction process it was seen that upgrading the armament was necessary to deal with "true" battleships protected against 14-16" armament.
Other armament then the 28 cm gun was not available when the construction started ; construction of a new construction gun lasts at least one year.
and they "needed " a counter as soon as posssible.

The number of shafts was depending on the horspower required to push a ship though the water, as the power transmisson screw -> water was limited by cavitation.

according to the knowledge of the time 3 shaft ships with conventional drive in general had a better propelling efficiency then a 4 shaft ship. So it was also used as a matter to save weight.

[RF]

The Germans always considered it a battleship.

This I think is more propaganda than reality, much the same as the pocket battleships were described as ''armoured cruisers.'' The River Plate battle demonstrated that Graf Spee was not an armoured ship as it suffered considerable damage from six inch shells, forcing it to seek sanctuary in a hostile neutral port.
Scharnhorst was conceived as an enlarged pocket battleship with a third turret. The British Admiralty description of battlecruiser I think was spot on.

If Scharnhorst was in your navy, would you pitch it one on one against USS Alaska?

[Thorsten Wahl]

Once more, the Scharnhorsts as constructed were meant to counter the Dunkerques.... with an option to upgrade the guns.

[lwd]

...
This I think is more propaganda than reality, much the same as the pocket battleships were described as ''armoured cruisers.'' The River Plate battle demonstrated that Graf Spee was not an armoured ship as it suffered considerable damage from six inch shells, forcing it to seek sanctuary in a hostile neutral port.

The fact that it took damage form 6" shells in no way indicates that it wasn't armored. Indeed one of the Japanese BB took damage from 40mm fire. The Graff Spee and company were designed to comply with the Treaty of Versailles which allowed the KM armored ships with the tonage and main guns they were designed with.

... If Scharnhorst was in your navy, would you pitch it one on one against USS Alaska?

While the design of the twins predates that of the Alaska's by less than a decade it was a decade that saw considerable advancements in technology and political landscape. As others have mentioned the twins were designed to take on the French equivalents.