If you set store by honoring those who fell in defense of the nation with something tangible, submariners can be a difficult lot, much like the whalers of old. However, Eternal Reefs may be what you’re looking for:
The “On Eternal Patrol Memorial Reef” will be the first-ever undersea memorial to honor the United States submarines and their crews that made the ultimate sacrifice and never returned from duty. Imagine 66 reef balls, one for each US-manned submarine lost since 1900 and a single reef ball honoring those lost in non-sinking incidents, forming a patriotic reef off the coast of Sarasota, Florida. It will forever pay tribute to those “On Eternal Patrol” and replenish the precious marine environment in which they served.
It’s crossed my mind more than once that humanity really should clean up after itself, even to the extent of raising wrecks and salvaging the hulks. Of course, this couldn’t possibly be done with current technologies, and some wrecks are actually beneficial, on balance, at their final locations.
Memorializing the lost submariners in this way sure seems appropriate. If you’re so inclined, they’ll accept donations.