As far as I inderstand it,the document in question (
https://invenio.bundesarchiv.de/invenio/direktlink/be9c3138-5bf0-458e-8203-e38ad7803aa4/ ,p. 50ff) is a reply from the navy to the army dating from jan 15th 1945.
The contetnt of the initial letter is not (yet?) known. However, we can deduce from
- the headline "construction of fast transportvessels for tanks",
- the explanations why neither the projected hydrofoils nor S-boats are able to fulfill that role,
- further explanations what tactical requirements were passed to and fulfilled by the navy (->MFP) in the recent years, and
- finally the demand that the army drops both the hydrofoil folly and the claim that the navy would have delayed the production of fast tank transports as demanded by the army
that the army initially complained about the navy delaying the construction of hydrofoil LCTs.
From the date I guess that the issue popped up due to the Red Army's
Vistula-Oder-offensive. Whether the army really believed that fast LCTs had changed the outcome or whether they just searched for a scapegoat I cannot say. The "proposal" of a LST like ship by the navy, however, is clearly just for feigning cooperation. Buisiness as usual in the face of total desaster...
Michi