One thing about the Manta Ray is that it has the same hull as a Viper, Warehouse Hobbies used to make. The only difference was the open hatch cover. If Enforcer Boats
https://enforcerrcboats.com/index.php?route=common/home has the mold yet for that hatch you could have two boats by switching hatch covers. Here's a pic of one with the Viper hatch on.