On Saturday morning, June 5th, 2021, while I was on the Block Island ferry heading to Block Island from Pt. Judith,RI, a one hour trip, I was on the lower deck as I had to stay with my motorcycle, looking west, a beautiful clear and sunny day with some choppiness to the ocean, I spied what at first I thought was a seagull flying low just inches above the waves, but realized quickly it was too low and too fast for a bird, and I saw no wings moving. Upon closer inspection the object, about 300 yards out, was silvery-white and did not vary from its path right at the water surface level. It was moving about 30 to 40 mph in a straight line. It would move below the water's surface and reappear as the waves had no effect on it. I tried to focus on the shape of the object but could only determine that it was about 18 inches in length and appeared to be somewhat cylinder shaped with two prongs sticking out from the underside. No lights were visible on it. It was ju! st plain odd and did not look like anything else I had ever seen on the water. It showed no wake or water disturbance. It past the ferry as it traveled south with the ferry; it was going faster than the ferry and then seemed to veer out further west toward a group of fishing boats gathered in one spot. I lost sight of it then. A few minutes later as I continued to look west another identical object, further out from where I first saw the first one, seemed to join the first one in that general area, both heading south and then a bit westward. They were fast and low. No sound was heard. I had binoculars but they were in my lock truck pack on the bike plus the boat was rocking due to wind and I didn't want to miss viewing the objects.