On our 40 Ocean it's a straight run from the bow filler down through a channel of fibreglass at the very tip of the bow, separating it from the anchor locker. The smaller tank vent hose runs parallel to it. Originally there was some fibreglass tabbed around the hose at the top (in the anchor locker), which wasn't a good solution as it let water pass along the outside of the hose from the anchor locker into the bow cabin. I fixed this with some self-amalgamating tape and adhesive sealant, which stopped the leaking.
To replace the hose, I would have to cut away that and some of the fibreglass tabbing, then make it waterproof around the new hose again. If you have the space, a bulkhead hose fitting would be nice, but on our boat at least there is no way to access the underside, so that wouldn't be possible.
It might be easier to just clean the hose in place instead