Flying boats? No no you can't have flying boats! That is Terrain issues..
P3Dv4.5 Tongass "boats".. Thinking.. hmmm.. Did you update the required entries in the terrain.cfg file?
(The required 40 Tongass Terrain.cfg entries for use in P3Dv4+ are appended/attached to this post.)Info:
https://return.mistymoorings.com/getting_started/index.php#5Once the terrain.cfg file is done/saved. (Sim off)
1. Delete the shaders folder >
Path >> C:\Users\your name\AppData\Local\Lockheed Martin\Prepar3D v4\Shaders
2. Delete the simobjects folder >
Path >> C:\Users\your name\AppData\Roaming\Lockheed Martin\Prepar3D v4\SimObjects
and
3. The sceneryindexes64 folder >
Path >> C:\ProgramData\Lockheed Martin\Prepar3D v4\SceneryIndexes_x64
That should fix Tongass on the sim's next start up.
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PS: Also for Tongass: did you update the AI models? >
https://return.mistymoorings.com/getting_started/index.php#9 (This saves CTD as the original models in Tongass are non-com[patible with P3Dv4x But Rod Jackson fifxed them all up to FSX Native/compatible with P3Dv4x and above).
Hope this cures your Tongass problem(s).
Norm