If you can't find a good boat cover, think about a retractable mount for your Ultrex. We have many customers who buy our mount because their boat covers no longer fit well and they are damaging the motor or just ripping the cover. With the Ultrex you would need a TMA-1 adapter plate and most likely, a SS-7-HD mount. Let us know if we can help.
www.shuttleslide.com/shop* We also sell an adapter plate (DPA-1) where you can reuse the existing hole pattern in your deck, so you don't have to drill new holes in your deck. You drill your pattern into the DPA plate and only attach that to your deck. We are having a sale until Memorial Day (info on our Facebook page).