3000 sounds like a reasonable guess and if it is then 300 on the tongue would be the standard minimum recomended, 10%. Some will tow well with less, some need more. I had a jet boat with almost no tongue weight (maybe ten lbs?) that towed awesome on a tandem axle trailer, but that's not recommended. My Donzi is 6K and has about 400 tongue and tows fine. With a single axle and small outboards they generally need more than a tandem axle and/or heavy engine, but it all comes down to the package.
Looking at your trailer photo I'd guess that you are over 10% and probably why it tows well.