Hauling boat in pickup bed while hauling TT.

You did not say how long the sun dolphin is.

Before I had my truck cap I made a U shaped rack for my 16 ft canoe. the posts of the rack dropped into the stake holes on the bed's sides and the cross piece was cab height.

I have a single Yakama rack on the cab for the front.

Now that I have the truck cap, the back of the canoe rides on it.

10 foot 2 inches
I would be looking at some type of rack.

I assume you have more than 55 inches tailgate width? I'd look for some way to adapt a plumbers rack type of thing to slide the boat on.someone recently had a small aluminum v bottom on a trailer perhaps they will jump in. I wanted to do this but couldn't find a boat/trailer combo that was narrow enough.
bumpy

I googled boat rack for truck. There were countless options.

I'm hauling a 17' canoe on a pair of Yakima Outdoorsman racks. F150 short box.

I was thinking of something like this.
Truck rack

16 foot royalex Bell Chestnut Prospector canoe sits on Thule racks on my k2500 sub.

I have a ladder rack installed over my tonneau cover to carry my kayak.

Thanks everyone, I think the ladder rack will need to fit the bill.

I haul 12 foot sit on top fishing Kayaks that weigh 100 lbs each on Yakima Outdoorsman Racks and it would work fine for your boat I would think.