I'll go even further. If somebody in the bay area (or anywhere) will drive over or ship me a powerful telescope (presumably more powerful what sounds to be TomB's crappy little refractor), I will personally and with fantastic care, drive it down to Monterrey on a brilliantly clear day (most days this time of year), set it up for him, and invite him out. We'll look at ships over the horizon, agree on what we see (at least descriptively), and take some pictures. Then I will gingerly repack it and ship it back with 24hour turnaround from Tom's viewing.
Here's what we'll do, bubbles. We won't even need to wait for a ship to depart from the harbour. You come over to Monterey with your camera, I'll secure a telescope, and we'll repeat together one of the bay experiments I preform regularly:
I live along the California Monterey Bay. It is a relatively long bay that sits next to the Pacific Ocean. The exact distance between the extremes of the Monterey Bay, Lovers Point in Pacific Grove and Lighthouse State Beach in Santa Cruz, is 33.4 statute miles. See this
map.
On a very clear and chilly day it is possible to see Lighthouse Beach from Lovers Point and vice versa. With a good telescope, laying down on the stomach at the edge of the shore on the Lovers Point beach 20 inches above the sea level it is possible to see people at the waters edge on the adjacent beach 33 miles away near the lighthouse. The entire beach is visible down to the water splashing upon the shore. Upon looking into the telescope I can see children running in and out of the water, splashing and playing. I can see people sun bathing at the shore and teenagers merrily throwing Frisbees to one another. I can see runners jogging along the water's edge with their dogs. From my vantage point the entire beach is visible.
IF the earth is a globe, and is 24,900 English statute miles in circumference, the surface of all standing water must have a certain degree of convexityevery part must be an arc of a circle. From the summit of any such arc there will exist a curvature or declination of 8 inches in the first statute mile. In the second mile the fall will be 32 inches; in the third mile, 72 inches, or 6 feet, as shown in
this chart. Ergo; looking at the opposite beach 30 miles away there should be a bulge of water over 600 feet tall blocking my view. There isn't.
Here's the math:
Suppose that the earth is a sphere with a
radius of 3,963 miles. If you are at a point P on the earth's surface and move tangent to the surface a distance of 1 mile then you can form a right angled triangle as in the diagram.
Looking over a distance of 1 mile, we can use the theorem of Pythagoras:
a
^{2} = 3,963
^{2} + 1
^{2} = 15,705,370
and when we square root that figure we get a = 3,963.000126 miles
Thus your position is 3,963.000126  3,963 = 0.000126 miles above the surface of the earth.
0.000126 miles = 12 in * 5,280 ft * 0.000126 mi = 7.98 inches
Hence after one mile the earth drops approximately
8 inches.

Ergo, looking across 30 miles the Pythagorean theorem becomes:
a
^{2} = 3963
^{2} +30
^{2} = 15,706,269
and when we square root that figure we get a = 3,963.113549 miles
Thus your position is 3,963.113549  3,963 = 0.113549 miles above the surface of the earth
0.113549 miles = 5,280 ft * 0.113549 mi = 599.53872 feet
Hence after 30 miles the earth drops approximately
600 feet.

Whenever I have doubts about the shape of the earth I simply walk outside my home, down to the beach, and perform this simple test. The same result comes up over and over throughout the year under a plethora of different atmospheric conditions. The last time I repeated this account before on this form the main response I get from RE proponents was to call me a liar.
With your testimony, we can help confirm that the earth truly is a plane.