That was as obviously wrong then as it is now, especially since tides move in a frequency much faster than annually. Perhaps if he hadn't gone there, the scientific leaders (including the ones in charge of the church's education) in his day might have been more open to dissing the Aristotelian world view in favor of the Copernican world view.
Although Kepler urged Galileo to validate his elliptical hypothesis, Galileo was a better experimenter and observer than analyst. In fact is it likely that Galileo could not calculate planetary positions using Copernican or Ptolemaic models. Owen Gingerich, in The Eye of Heaven: Ptolemy, Copernicus, Kepler shows convincingly that the Copernican model was no more accurate than the Ptolemaic model in predicting the position of planets or explaining their observed positions. Both were occasionally months off in predicting retrograde motion, and had roughly equal RMS errors in position. The advantage of the Ptolemaic model was that is was much simpler to use, requiring fewer calculations, and fewer parameters to model. The one advantage of the Copernican model was that it did not require the distance to the moon to change by a factor of two in the course of month, a phenomenon not observed, as the angular diameter of the moon only changes by few percent. A further perceived advantage of the Copernican model was that it resolved planetary motion into a combination of uniform circular motions, at the expense of simplicity. Ptolemy accounted for the effect of Kepler's second law by introduction of the much hated equant, which violated Aristotle's injunction that planetary motion must be resolved into uniform circular motions. This is an aesthetic consideration, not a scientific one. The Keplerian model was distinctly more accurate, but required solving a transcendental equation, at time when only a handful of mathematicians even knew how solve polynomial equations higher than quadratic.
Where Galileo got into trouble with the church is with the publication of Dialogue Concerning the Two Chief World Systems. Pope Urban VIII had been a friend of Galileo's and reviewed a draft of Dialogue. He asked a few questions about the treatment of tides. Galileo told him he would clarify those points in final draft. What Galileo did was put the Pope's questions in the mouth of the doltish character of Simplicio, and has the all-wise interlocutor Salviati dismissively swat them away. Unfortunately, the Pope's questions were reasonable, and Galileo's response was sophistry. Galileo also had a rural prelate provide the Imprimatur for the final draft, to avoid any Vatican interference. Kinda guy who could piss off the Pope.