Backstay?
If your boom is long enough, and you have a backstay, try a tarp over the boom.Not very elegant, but it works.Also, there are some boom tents and umbrellas you can suspend from the main halyard and strap to the lifelines you might consider.West Marine and most local boat cover shops can fabricate a real nice bimini.My h26 has a bimini that can not be used while sailing, because of the mainsheet placement in the cockpit, but shade while motoring or mooring is better than nothing.