Barnacle free tandem island hull cover

I moved from fresh water to salt/brackish and searched this forum for ideas of how to store my TI at a slip without barnacle damage. The O’Brien Ultra foam mat was sold out so I searched for alternatives and found dockydock.com which makes custom “drive into/onto” barnacle free hull boat covers which have submerged covers held up by floating foam perimeters in the shape of the hull. Once the boat is in the submerged cover the rear gate is closed by pulling up the submerged entrance part of the hull cover trapping the salt water around the hull which is then pumped out making the loose submerged cover cling to the shape of the hull up to the floating foam rim. It prevents barnacle and other marine growth by starving them of nutrients and oxygen according to the dockydock FAQ.
This seemed like a great idea for protecting Hobie Islands if it had the right kind of marine grade water proof tarp supported by pool noodles if required. Then pump out the trapped salt water using a battery powered hand pump placed in the mirage drive well so the loose fitting tarp clings to the hull. Not clear what the best tarp material might be but perhaps a PVC or vinyl coated tarp 6x25 feet might do the trick. In may not be necessary to use pool noodles for the entire rim but rather use bungee cords secured to the top of the boat through the grommets to hold the hull cover securely. An exact shape is not necessary since water pressure when pumped empty would force the tarp to cling to the shape since loose fitting is necessary slack required to squeeze all the salt water out. If it rains that water is fresh which barnacles cannot tolerate though too much rain may submerge the boat bringing the barnacle environment back. Therefore a boat top cover would be needed perhaps. This could be done using a larger tarp such as 12x 25’ but grommeted at the mid 6’ foot line where half is the hull submerged cover and the other half the sun/rain top cover. Rather than drive into the hull cover perhaps a half circle aluminum tool can drag the hull cover lengthwise from front to back below the boat while the intermittent foam rim floats keep it from sinking until grommet cord is hooked on top of boat on both sides.
The ultra floating mat is about $800 but tarps are cheap and a hand held battery powered water pump is less than $30. So even if the elements or some barnacle get on it, just discard it for a new tarp.

I have ordered the pump but need advice on the type of tarp that best repels barnacles.
The dockydock solution must be working since they have been in business for several years. Look at their gallery photos and YouTube to see examples for big boats.
Bob

Seems like alot of work. How did it work out for you?