candidate. "They have to be comfortable in the water," says Bisset who adds that the attrition problem is not only manifested during BUD/S training, but in boot camp where many of the improperly screened candidates fail the swim test.

"If they fail the test, the contract is not consummated and they don't get to go to BUD/S, they are sent to the fleet," he says. "Last year, only 39 percent of candidates were able to pass the initial screen test in boot camp. Fifty percent of those failing to pass the test were dropped due to failing the swim portion. Well, that works out okay for the Navy, but not the SEALs."

SEAL candidates who are fortunate enough to be mentored by Bisset and his staff certainly have an edge over their non-mentored peers going into SEAL training.

Those who meet the recommended SEAL RDAC physical fitness scores have a BUD/S graduation rate of 70 percent. The graduation rate of those who don't go through Bisset's program is between 20 and 25 percent.

Despite its enormous success, the program is not foolproof. Nothing is when it comes to training commandos for war. "Some kids are PT studs and they still end up quitting," says Bisset. SEAL training is extremely tough, "and it is just so hard to get into the heart and brain of the man who says he wants to be a SEAL."

This article first appeared in NavySEALS.com.