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We designed and built our own cantilever-style bimini and had a local canvas shop fabricate the shades and canvas to our specifications. Pretty attractive and user friendly assembly overall.

The side shades are zippered to the bimini top with integrated zipper flaps with loopson the bottom to hook to the hand rails. Five removable roll-up panels total. I prototyped the frame in 3/4 inch PVC, full scale and attached to boat to prove design concept and work out final design. This was really a fun project and we saved gobs of $$ in the process. The total cost was around $3000. Which included a professional tubing bender and 1 in. die for $600. Design software included. I had a tubing notcher and tig equipment already.
A local boat rail fabricator quoted $7600. His work is awesome. And we may have justified the cost. But the lead time was too far out. Motivation comes in many forms.

Design Approach and Basic Elements

Frame:
1” diameter 304 SS tubing. Notch and weld all joints. Mechanical attachments four places.
Cantilever frame attached to sun deck stanchions.
No other supports if possible. Removable struts if necessary. (We like to fish out the back so no obstructions for fishing poles and bodies.)
Limit or eliminate frame to boat weldments. (Removable)
Lace-on top (because we like the look) with zip open trap door to sun deck.

Sunshades:
Five panels. Roll-up or remove as necessary.
Straps with twist fastener, looped around hand rails.
Side curtains fold back half way and snap open at entry way.
LED flood lights around frame and inside bimini. I fished steel cable inside tubes before welding to pull feed wires. Made provisions to service or replace wires if needed. Individual light switches inside rear door.

Final Observations

We sure love it! Worked out cantilever angles to maintain adequate support and not have head knockers while boarding. We walk by the frame without much regard for it at all. The frame is an obvious hand hold. We had an unplanned test when a visitor slipped while boarding and was hanging with both hands from the lower rung of the frame and both feet overboard. He was an easy 230 lbs. He and the frame had no ill effects. The frame exceeded my expectations in stiffness in all directions. Just amazing actually. No you cannot hang from the rear tube. Too far away as an obvious hand hold anyway. I did not pull off the easily removable requirement totally. There are two weldments at the ladder. I could have got around this now that I think of it. I may build another one sometime after we critique this one awhile.