Nevermind I checked and the russian MIR subs had THREE viewports.
>The Mir submersibles are 7.8 m long, 3.6 m wide, 3.0 m high, and weigh 18,600 kg (maximum payload is 290 kg). The personnel sphere's walls are 5 cm thick, and the inside diameter of the working area is 2.1 m. Three viewports are provided (viewport material is 18 cm thick): the forward-facing port is 20 cm diameter; the two side-facing ports are 12 cm diameter each.
So they paid 200 hundred thousand more dollars for a smaller viewport that was above a toilet. And it also killed them.
Again not to get political but just rent the russian sub. It was a wiser choice all around.