I just spoke to PayPal on phone. Very different than when the bot services you. Decided in my favor, but for an unexpected reason. It was not the I had emails proving he got the e-plans; which he specifically requested. It was that the plans were emailed. “Intangibles are not covered by a claim.” Damn. I did not know that. I have always said that IBEX needs seminars on e-commerce, but they always ignore me.
Glad that it turned out this way. The only recommendation I can make is a disclaimer that your plans do not include pilot chart studies and user usage (user has to know his purpose). You can sell that service separately.
A while ago I remember reading a performance analysis by John Shuttelworth yacht designs (on his website) about the weight of multihulls and chop/wind.
I experienced North Atlantic designs (US, Canadian, Danish) in the Pacific. You simply can not make it to your destination without propulsion. Very frustrating when you are so close too!