The Great Escape

Matt black disk with wake of a rowing scull on it. Wake gloss black? gloss white? silver lustre?

Rowing Scull

Length approx 8.2m / 27ft - say LWL = 8. Min wt 14kg.
Average speed 5.3m/s by a competitive rower.
Froude No = V/√(g.L) = 5.3/√(9.81.8) = 0.598

Wakes and Oar Ripples

Shallow Water

Shallow water when V > (gd)^½
5.3 > (9.81d)^½
d < 2.86m
This is likely in a river, so go for shallow water

Wake angle off CL, 𝛽: 𝛽=sin^-1[(gd)^0.5/V

d / V	3	4	5.3
0.5	47.5	33.6	24.7
1	-	51.5	36.2
1.5	-	73.5	46.4
2	-	-	56.7
2.5	-	-	69.1
2.85	-	-	86.1

Deep Water

Cusp pattern: https://personal.math.ubc.ca/~cass/courses/m309-01a/carmen/Mainpage.htm
or https://farside.ph.utexas.edu/teaching/315/Waveshtml/node70.html
𝛽 = 19.5 at the outside, 15 on the inside
Correcting for higher speed gives 17.8° on the outside, so say 13.3 on the inside
See http://www.fast.u-psud.fr/~moisy/papers/2013_rabaud_prl.pdf and https://www.pct.espci.fr/~elie/Publications/Kelvin_wake_pattern.pdf for high speed effects
Angle of waves ≈53° to the direction of travel
Transverse waves lower than at slow speed as Fr > 0.5, but still there

Images

Note irregularity as speed varies https://t4.ftcdn.net/jpg/01/11/47/71/360_F_111477186_FAnmtxWZ1nfkHhtjHXqIugpPFvLzNO6S.jpg
https://www.google.com/search?q=rowing+boat+from+above&tbm=isch&hl=en-GB&sa=X&ved=2ahUKEwignb-er6z3AhUCSkEAHVkhC1MQtI8BKAB6BAgAEDI
https://www.google.com/imgres?imgurl=https%3A%2F%2Froweracademy.com%2Fwp-content%2Fuploads%2F2019%2F07%2Frower_academy_1800x500-above.jpg&imgrefurl=https%3A%2F%2Froweracademy.com%2Fcategory%2Frowers%2Ftechnique%2Fpage%2F2%2F&tbnid=1UNPqj_xd8nT0M&vet=12ahUKEwirkeyXyaj3AhXO4YUKHcBk4QMygMegUIARC3AQ..i&docid=WWqFzvLaSGpnFM&w=1800&h=500&itg=1&q=single%20rowing%20from%20above&hl=en-GB&ved=2ahUKEwirkeyXyaj3AhXO4YUKHcBk4QMygMegUIARC3AQ
Good for oar wakes: https://www.google.com/search?q=single+rowing+from+above&tbm=isch&hl=en-GB&tbs=rimg:Cb5mkurAtcJQYa1v_1yW5xnDa&sa=X&ved=2ahUKEwiuvp6Iyaj3AhVYiFwKHazeAvoQuIIBegQIABAr&biw=1903&bih=1112
https://www.google.com/search?sxsrf=APq-WBuVE-r-BAcicwRCW1DtOYZzyl20cQ:1650661336792&source=univ&tbm=isch&q=rowing+skiff+from+above&fir=MHYv3MgfmnBMxM%252CWs7yZikqxZVFFM%252C_%253Bd45fLuvjKILqwM%252CIhC39tXW-eS41M%252C_%253B2pEyICQozLMBKM%252CIhC39tXW-eS41M%252C_%253Bo2KpOO0rRYKj8M%252C7HBytSLSlssr3M%252C_%253B9Y7s1uyKGyzv_M%252CLdPppiK6DWrqpM%252C_%253BSVISR31LJ30AIM%252CxZABmGfn0jhw1M%252C_%253Bwl9jT_cQXcEKwM%252CQjeKSZxfGFRNdM%252C_%253BECJaFT89tWzBZM%252CxZABmGfn0jhw1M%252C_&usg=AI4_-kQHwZPt9BNUXL_cy3ZzctRC7CGnXw&sa=X&ved=2ahUKEwic1_7UyKj3AhXgQkEAHakjAoIQ7Al6BAgKED8&biw=1920&bih=1112&dpr=1