On the morning of 7 May 1944, Kapitänleutnant Eberhard Zimmerman, commander of the U-548, spotted a Canadian Frigate, HMCS Valleyfield in the crosshairs of his periscope. He launched two GNATs, acoustic torpedoes, one of which struck the River Frigate near her boiler, splitting the ship in two, and four minutes later, the Valleyfield began its final voyage to the bottom of the Atlantic. Of the 163 crew on board (see chart below), only 43 were rescued.
| Name | Age | Rank | |
| Addison, Henry Charles, RCNVR | Able Seaman | ||
| Anderson, Norman William, RCNVR | Ordinary Seaman | ||
| Arseneault, Willard George, RCNVR | 26 | Leading Stoker | |
| Attwood, Albert James, RCNVR | 46 | Leading Steward | |
| Avery, William Harold, RCNVR | Stoker 1st Class | ||
| Avey, Sydney Charles, RCNVR | 19 | Stoker | |
| Barefoot, Gordon William, RCNVR | 20 | Stoker | |
| Baulne, Joseph Emile René, RCNVR | Able Seaman | ||
| Blochlinger, John Emile, RCNVR | 31 | Petty Officer Stoker | |
| Bolitho, Samuel Symonds, RCNVR | 38 | Engine Room Artificer | |
| Boucher, George Arthur, RCNVR | 23 | Able Seaman | |
| Boudreau, Leonard James, RCNR | 27 | Petty Officer Stoker | |
| Boutilier, Ralph Howard, RCNR | 29 | Petty Officer Stoker | |
| Bouvier, Theodore Joseph, RCNVR | 23 | Signalman | |
| Brault, Roland, RCNVR | 21 | Able Seaman | |
| Brown, David Edgar, RCNVR | 19 | Able Seaman | |
| Brown, David Henry, RCNVR | 28 | Leading Seaman | |
| Burns, Edward Richard, RCNVR | 22 | Cook | |
| Burton, William Clarence, RCNVR | 26 | Supply Assistant | |
| Byron, John, RNR | 53 | Commander | |
| Cant, Daniel, RCNVR | 19 | Stoker | |
| Carey, Percival George, RCNVR | 28 | Able Seaman | |
| Chiesa, John Delkie, RCNVR | Stoker 2nd Class | ||
| Cooke, Dwight Russell, RCNVR | 26 | Petty Officer Stoker | |
| Cornwall, James Anthony, RCNVR | 20 | Able Seaman | |
| Daley, Robert E., RN | Telegraphist | ||
| Daoust, Joseph Harold Hector, RCNVR | 19 | Stoker | |
| Daubs, William, RCNVR | Steward | ||
| Davey, William, RCNVR | 20 | Able Seaman | |
| Dawes, James Calvin, RCNVR | 22 | Able Seaman | |
| Denis, William, RCNVR | 25 | Telegraphist | |
| Deslauriers, Joseph Jacques Uldege, RCNVR | 20 | Stoker | |
| DeWare, Noble Horton, RCNVR | Able Seaman | ||
| Dickenson, Reginald George, RN | Telegraphist | ||
| Donohue, Donald Thomas, RCNVR | 21 | Ordinary Seaman | |
| Dupuis, Raymond Clifford, RCNR | 21 | Able Seaman | |
| Edwards, William Lawrence, RCNVR | 20 | Stoker 1st Class | |
| English, Dermot Thomas, RCNR | 33 | Lieutenant Commander | |
| Erskine, William, RCNVR | Stoker 1st Class | ||
| Flath, John Carleton, RCNVR | 30 | Lieutenant | |
| Flude, Albert Edward, RCNVR | Ordinary Seaman | ||
| Friesen, Louis, RCNVR | 29 | Petty Officer Stoker | |
| Garrioch, Elmer George, RCNVR | 26 | Able Seaman | |
| Gauthier, Joseph Alphonse Jean Paul, RCNVR | 27 | Engine Room Artificer | |
| Gibson, Donald Harry, RCNVR | Telegraphist | ||
| Giles, David Henry, RCNVR | 19 | Able Seaman | |
| Godwin, Donald Harold, RCNVR | 20 | Ordinary Seaman | |
| Goss, Robert William, RCNVR | 19 | Able Seaman | |
| Graham, Douglas George, RCNVR | 23 | Leading Supply Assistant | |
| Griffin, John Albert, RCNVR | 18 | Ordinary Seaman | |
| Guilbault, Joseph Rene Celestin, RCNVR | 18 | Able Seaman | |
| Guthrie, Robert Milford, RCN | 20 | Leading Seaman | |
| Hammick, Laurence Almeric, RCNVR | Signalman | ||
| Hancock, Charles Clifford Nelson, RNPS | 22 | Ordinary Telegraphist | |
| Harding, Percival Roy, RCNVR | 20 | Able Seaman | |
| Harvey, Stanley Frederick, RCNVR | 23 | Petty Officer | |
| Hoffman, Martin John, RCNVR | 22 | Ordnance Artificer 4th Class | |
| Howe, Ralph Ingraham, RCNVR | 18 | Ordinary Seaman | |
| Howlett, Robert Floyd, RCNVR | 23 | Supply Assistant | |
| Ioanin, George Albert, RCNVR | Ordinary Seaman | ||
| Irvine, Clarence Edward, RCNVR | 36 | Surgeon Lieutenant | |
| Irwin, William Charles, RCNVR | 20 | Able Seaman | |
| Ivy, William Edward, RCNVR | Petty Officer Telegraphist | ||
| Jobin, Joseph Romeo Gaston, RCNVR | 25 | Leading Seaman | |
| Johnson, Lorne Irwin Clinton, RCNVR | Ordinary Seaman | ||
| Johnston, John Stewart, RCNVR | 35 | Engine Room Artificer | |
| Kaplan, Irving Jack, RCNVR | Yeoman of Signals | ||
| King, Albert Edward, RCNVR | 20 | Radio Artificer | |
| Knight, Raymond Edward, RCNVR | 18 | Ordinary Seaman | |
| Laing, Ellsworth Clark, RCNVR | Ordinary Seaman | ||
| Lariviere, Joseph Arthur Adrien Gerard, RCNVR | 20 | Able Seaman | |
| Laviolette, James Ferdinand, RCNVR | Chief Petty Officer | ||
| Law, Jack Fraser, RCNVR | Able Seaman | ||
| Layton, Paul Chisholm, RCNVR | 24 | Leading Writer | |
| Le Drew, Rexford Stanfield, RN | Engine Room Mechanic 4th Class | ||
| Lee, Frank Edward, RCNVR | 24 | Able Seaman | |
| Lennox, Allan John, RCNVR | 22 | Telegraphist | |
| Lockwood, Harold Laverne, RCNVR | 20 | Ordinary Seaman | |
| Long, Jeffrey Alfred, RCNVR | 19 | Ordinary Seaman | |
| Lonsberry, Frederick Murray, RCNVR | 21 | Able Seaman | |
| Lyons, Nelson, RCNVR | 22 | Stoker | |
| Maclachlan, George Alan, RCNVR | 22 | Lieutenant | |
| Maclaren, Ian Pearson, RCNVR | 23 | Lieutenant | |
| Maclean, James Douglas, RCNVR | 22 | Engine Room Artificer | |
| Martin, Leslie Frederick, RCNVR | Stoker 2nd Class | ||
| Mason, Stirling Cashman, RCNVR | 22 | Lieutenant | |
| McCue, Thomas Bernard, RCNVR | 20 | Steward | |
| McDonald, Richard Alexander Angus, RCNVR | 20 | Able Seaman | |
| McGettigan, Emmett Patrick, RCNVR | 25 | Leading Cook | |
| McGibbon, John Donald, RCNVR | 19 | Ordinary Seaman | |
| McGregor, Alexander Murray, RCNVR | Cook (S) | ||
| McLaughlin, Russell Lewis, RCNVR | Telegraphist | ||
| McNeill, Bernard James, RCNVR | 19 | Able Seaman | |
| Menzies, Joseph Blair, RCNVR | 30 | Engine Room Artificer | |
| Mills, Archie William, RCNVR | 37 | Coder | |
| Mooney, Francis Joseph, RCNVR | 21 | Stoker | |
| Moore, William Wallace, RCNVR | 20 | Able Seaman | |
| Mulcahy, Daniel, RCNVR | 27 | Stoker | |
| Munro, Edward Donald, RCNVR | Coder | ||
| Murphy, John William, RCNR | 32 | Engine Room Artificer | |
| Murray, Leon James Ashworth, RCNVR | 28 | Stoker | |
| Nadeau, Joseph Raoul Rolland, RCNVR | 25 | Able Seaman | |
| Nelson, Terrence Dominic, RCNVR | 19 | Signalman | |
| Newman, Clifford Jerome, RCNVR | 25 | Engine Room Artificer | |
| Nichols, Percy Merrill, RCNVR | 23 | Able Seaman | |
| Noble, Wilfred James, RNPS | Steward | ||
| Norman, Harry, RN | 19 | Telegraphist | |
| O’Connor, Terrence Patrick, RCNVR | Signalman | ||
| O’Grady, Daniel George, RCNVR | Engine Room Artificer 4th Class | ||
| Oakley, Victor Sydney, RCNVR | 23 | Telegraphist | |
| Oke, Frederick George, RCNVR | 23 | Leading Sick Berth Attendant | |
| Orme, William Leslie, RCNVR | 22 | Petty Officer | |
| Ozon, Gerald Thomas, RCNVR | 20 | Steward | |
| Pedwell, Jack Aldon, RCNR | 24 | Leading Stoker | |
| Perry, Roland, RCNVR | Able Seaman | ||
| Phillips, Ronald Keith, RCNVR | 18 | Ordinary Seaman | |
| Poole, Donald James, RCN | 21 | Petty Officer | |
| Porter, John David, RCNVR | 19 | Able Seaman | |
| Ralph, Georg, RCN | 20 | Able Seaman | |
| Randall, Walter Gordon, RCN | 19 | Leading Seaman | |
| Raymond, Paul Joseph Russell, RCNVR | 21 | Able Seaman | |
| Reynolds, Frank Clarin, RCNVR | 31 | Lieutenant | |
| Ridout, William George, RCNVR | 26 | Lieutenant | |
| Rudd, John Sydney, RCNVR | 21 | Leading Coder | |
| Russ, Clyde, RCNVR | Able Seaman | ||
| Sanger, Lewis John, RCNVR | 23 | Lieutenant | |
| Schofield, Darcy Joseph Milton, RCNVR | 19 | Cook | |
| Sieber, Thomas Joseph, RCNVR | Ordinary Coder | ||
| Sillers, John Alfred, RCNVR | 21 | Telegraphist | |
| Sinclair, Eric William, RCNVR | 31 | Able Seaman | |
| Skurdaskas, Thaddeus Joseph, RCNVR | Leading Seaman | ||
| Snider, Richard Samuel, RCNVR | Ordinary Telegraphist | ||
| Stevens, Cyril Edward, RCNVR | 21 | Ordinary Seaman | |
| Storey, John Edmund, RCNVR | 27 | Passenger (Lieutenant (E)) | |
| Strachan, Edward Eloi, RCNVR | 20 | Telegraphist | |
| Stringer, Joseph, RCNVR | 20 | Able Seaman | |
| Sullivan, Samuel, RCNVR | 26 | Telegraphist | |
| Sutton, Kenneth Roger, RCNVR | 25 | Paymaster Lieutenant | |
| Swales, Leroy Stilson, RCNVR | 24 | Steward | |
| Tapson, Stanley Carson, RCNVR | Stoker 1st Class | ||
| Tate, Charles Ian Passman, RCNVR | 22 | Lieutenant | |
| Templeton, Thomas McDonald, RCNVR | 25 | Leading Seaman | |
| Therrien, Joseph Hector Clarence, RCNVR | 26 | Shipwright 4th Class | |
| Topp, Charles James, RCNVR | 26 | Leading Stoker | |
| Urquhart, Harold Frederick, RCNVR | 23 | Petty Officer Stoker | |
| Valiquette, Raymond James, RCNVR | 24 | Petty Officer | |
| Wakeley, Stanley Gordon, RCNVR | 19 | Able Seaman | |
| Walker, Robert Thomas, RCNVR | 27 | Able Seaman | |
| Ward, Victor Albert, RCNVR | 25 | Signalman | |
| Warren, Jack Hamilton, RCNVR | Lieutenant | ||
| Watson, John Crittenden, RCNVR | 25 | Lieutenant (E) | |
| West, Robert Evans, RCNVR | 20 | Stoker | |
| Whitlock, Roy Nelson, RCNVR | 20 | Ordinary Seaman | |
| Willard, John Murray, RCNVR | Leading Stoker | ||
| Willis, Stanley Turnbull, RCN | 24 | Leading Stoker | |
| Wilson, Murray Francis, RCNVR | 19 | Able Seaman | |
| Wilson, Robert Harvey, RCNVR | 19 | Able Seaman | |
| Wilson, Roderick Arnold, RCN | 25 | Chief Petty Officer Stoker | |
| Windsor, Frank Louis, RCNVR | 23 | Able Seaman | |
| Woods, Mervyl Harrison, RCNVR | 20 | Able Seaman | |
| Woolridge, George Leslie, RCNVR | 19 | Able Seaman | |
| Yeo, Bertram Thomas, RCNVR | Leading Stoker | ||
| Young, James Earl, RCNVR | 24 | Able Seaman | |