I look forward to reading this translated work. I beg your forbearance if the following does not appear to be directly of relevance – I don’t think this is a matter of semantics.
From « avant-propos » p ii of « Le bataillon des marins de la Garde, 1803-1815, (1905) Eugène Lomier, Jean Baptiste Grivel (baron), Publisher Impr. E. Lefebvre
« Napoléon 1er, qui se connaissait en hommes, a dit des Marins : On les a trouvés, au besoin, matelots, soldats, artilleurs, pontonniers, tout ! »
I have been perusing this work together with a short article by a certain Jean Sarramon recently entitled Marine Land Operations in the Peninsular War in "New Lights on the Peninsular War: International Congress on the Iberian Peninsula (Selected Papers) 1780-1840"
Whilst there would have been many a sailor in both the “marins de la garde” and the relevant ranks of the “equipages de la flotille” it would appear preposterous to suggest that they were formed or operated as “sailors” for any protracted period from 1803 onwards (even perhaps during 1804 – 1805). The 44e were indeed allocated as HQ and hospital guard during the third invasion of Portugal (amongst other duties) but did not do any sailing as far as I can tell.
Whilst there is clearly a nautical origin in their formation and appearance etc (e.g. the retention of naval titles for officers and the use of anchor insignia), they would appear to have operated as primarily land based troops (and perhaps most often as infantry) throughout the period. Indeed, it would also appear that at least half of the other ranks of the “equipages de la flotille” were comprised of workers – most likely including stevedores, dockers, dock labourers and longshoremen and such like in their number as well as ship builders and pontonniers etc.
It would appear to me, and here I admit I do not have a good grasp of French, that “marins” is clearly a generic term to identify / differentiate these units from infantry (garde, line and light) and cannot simply be reduced to the single term sailor – matelot.
With the exception of the navigation of small craft on rivers in mainland Europe and the Iberian peninsula, this would appear to be one operation these troops were not asked to undertake – at least commonly.