Hi I am building a seaplane similar to the ones attached. Could someone please explain to me the importance of an upwards thrust line on a seaplane? The plans I have call for 3 degree upwards thust line and I can't figure out what the purpose of it is. I am used to building downwards thrust lines on conventional prop driven planes so they don't climb when throttle is applied.
Any clarification on the sublect would be appreciated, Ilike to understand why I am building something a certain way.
Thanks,

Essar.</p>