Film makers always have to work to a budget and use what is available, even if the story is compromised. It is always possible that the original (fictional) story was wrong, in this case the use of a lease-lend Grumman MIGHT have been more likely than a Swordfish.
And was it not true that bits of Vanguard starred as bits of various WW2 German warships?
It is no use expecting the general public who are 99% of the audience to be able to spot corner cutting by the props department, as they are just watching pictures. Gaffes by the continuity department, thinking here of wild west trains pounding across prairies with curiously interchangeable wheels and funnels, and planes with variable numbers of engines, are something else.
One of the greatest sea films must have been "Cruel Sea", and that had the "wrong" type corvette, but they had to use what was available.
The annoying thing is Discovery Channel - the number of times the same bit of stock has been used for a sinking merchantman from both world wars, the number of times the destruction of Barham has represented the sinking of a large capital ship from any number of navies is annoying when you consider that the programs are aimed at a basically anorak audience who can and will spot these things, rather than the general public, who can't.