Stuck on science cap

You can craft compendiums. You may not have a tech to spend them on, but there is no cap on them, and you can turn them into blueprints as needed later (needed for both later techs and several important buildings). As a very minor fringe benefit, each compendium also adds +10 to your science cap. You just need to build up enough manuscripts to where bleeding off the excess science is easy on a whim, so anything that gets you fur (to convert to parchment) and culture would be important. If the compendiums pile up, start converting them to blueprints, which also bleeds off science, although much more.

You can also spend science on Academies, whose largest cost is mainly science (with a bit of wood and minerals), and which also increases your science cap. It also isn't hard to max out the building this way, so unfortunately this will only take you so far. Observatories cost Science as well - you may think they will just increase your stellar events, and put you in the same situation, but more star charts is never a bad thing in the long run. It's just, as you said, building up the wood, which can drag on for a bit.

Oh -- my mistake:

clarification:

With 303.670 ships, my Harbour capacity is 7711.224catnip / 23.459Kwood / 31.837K minerals / 5026.947 iron / 948.481 coal / 158.080 gold / 316.160 titanium.

With 308.400 ships, my Harbour capacity is 7721.215catnip / 23.489Kwood / 31.879K minerals / 5033.460 iron / 949.709 coal / 158.285 gold / 316.570 titanium.

So I guess I hit the Diminishing Returns knee in the curve, I was expecting it to be more gradual.