I can recommend two. In the U.S., the Nautical Research Journal deals with scale ship models, generally of a high standard. It deals with other maritime/naval topics as well; it has, in fact, been the target of some criticism from ship modelers who don't find some of the non-modeling topics particularly interesting. In fact the percentage of the magazine devoted to models varies from issue to issue - largely depending on what's been sent to the editor. It's published quarterly, so it's entirely possible for a year to go by in which an individual modeler won't find much that especially interests him/her. And the next year may see four issues that the same individual finds fascinating.
The NRJ's parent organization, the Nautical Research Guild, produces a set of CDs containing all issues of the Journal since 1949. Those CDs are surely one of the biggest bargains in ship modeling.
My vote for best magazine devoted strictly to scale ship modeling goes to the British quarterly Model Shipwright. It's also pretty selective about what it publishes; there's not a great deal in it for newcomers, but some of the models featured in it are among the best you'll ever see. The coverage includes every aspect of scale ship modeling, from 1/1200 waterline merchantmen to enormous RC models. Subscriptions are on the expensive side - largely due to the lousy state of the dollar relative to the pound, and to the expense of airmail delivery. But in my opinion it's worth it.
Quite a few back issues of Model Shipwright are, rather surprisingly, available through Barnes and Noble. Just go to www.bn.com and type "Model Shipwright" into the search engine.
The model club to which I belong voted some years ago to take an approach toward magazine subscriptions that I think is a good idea. We meet at the North Carolina Maritime Museum in Beaufort (next meeting Saturday, September 27, at 2:00; new members and guests always welcome). The museum has a small library and several computers and printers that are available to club members. We used a chunk of the club treasury to buy a subscription to Model Shipwright for the library, and we bought a set of the NRG CDs for use by any club members who want to use them. It's a nice, convenient arrangement - especially for those members who, unlike me, live within an easy drive of the museum. We're lucky in being affiliated with a museum and library, but I suspect lots of public libraries would welcome the gift of a subscription from a model club.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.