Udi,
Rigid solar panels are relatively inexpensive and long lasting but heavy and require solid SS support frame. Weight and size of solar panels are tied directly to power output. High efficiency monocrystalline rigid 100W panel weight is between 15 to over 25 lbs plus support tubing. So four rigid 100W panels and tubing will weight probably more than your anchor.
In order to reduce total weight, I installed 4 x 1”OD x .049” WT SS tubes attached to FWD and AFT bimini arches and used two semi-flexible high efficiency 100W panels, each 3.5 lbs (ordered from China). I made frame supporting each panel from used, discarded fibreglass hokey sticks. There is room above bimini for 400W panels. Attached pics are done during installation.