Uma explicação razoável que eu posso ver ...
Os homens já estavam nos navios . Apenas os capitães votaram no Kingsmoot
The kingsmoot was a traditional ceremony held by inhabitants of the Iron Islands in which kings were chosen by longship captains
O GRRM disse o seguinte sobre o tamanho da frota de ferro :
In brief, though... the Iron Islands can float a lot more than a hundred ships. Each of the major lords probably commands that any.
However, it is important to remember that the longships are smaller and simpler than the fleets that Joffrey and Stannis warred with on the Blackwater. The former are Viking longboats, more or less; for the latter, think Venetian/Byzantine dromonds of war.