love it when that happens!! bag the shit out of a site, witch turns around to bite ya in the bum!! swelmap usally is a touch on the small side, i beleave thats because surfers depend on it! so they tone it down a little so if its bigger it a bonus for em?? where as the marine site is just that therefore they tone it right up, for safty reasons ....usauly that site is on the huge side of things?
when ya go fishing its always good to cross cheek against all sites and take an average, i use 4 sites, all differ but at least it gives you a better bearing on things! same applys with the wind forcast!