oh

select *
from (
    select
        DP.port_id,
        S.ship_id,
        count(S.ship_id) as Cnt,
        V.voyage_id
    from       Captain_Ship_Voyage as CSV
    inner join Voyage              as V   on V.voyage_id = CSV.voyage_id
    inner join DestPoint           as DP  on DP.voyage_id = V.voyage_id
    inner join Ship                as S   on S.ship_id = CSV.ship_id
    group by Dp.port_id, S.[name], S.ship_id, V.voyage_id
) as tmptmt
where
    Cnt = (
        select max(Cnt)
        from (
            select
                count(ISh.ship_id) as Cnt
            from       Captain_Ship_Voyage as ICSV
            inner join Voyage              as IV   on IV.voyage_id = ICSV.voyage_id
            inner join DestPoint           as IDP  on IDP.voyage_id = IV.voyage_id
            inner join Ship                as ISh  on ISh.ship_id = ICSV.ship_id
            where
                IV.voyage_id = tmptmt.voyage_id
            group by IDp.port_id, ISh.[name], ISh.ship_id
        ) as tmpp
    )