Now I understand your terminology Peregreno. For a manual "tactical peek" sounds much more official than "porpoise".
That's loke saying ossifers dine on vagina while NCO's eat pu$$Y.
Your assessment of the tactical use of SCUBA is so true. As for the tactical peek, consider where the swimmers came from. Unless it was from an escape trunk of a sub, they were cast from surface craft. Then they had to set their compasses. All of this on the surface. A 5 second peek after 50 meters or so isn't going to be any more compromising.
SF has many other uses for SF swimmers. In Panama we blew channels through the barrier reefs to allow fishermen easier access to the open water. We also blew all of the tree stumps in the Gatun rec areadown to 6 feet under water. In Germany, TURD (Trojan Underwater Recovery Detachment) was used for just that. In Thailand we recovered several submerged T-28s belonging to the RLAF. In Vietnam divers were used to inspect and clear piers and waterways.
