The 28-29 on the right is definitely quite a nice car, shiny paint, 32 shell, 35 wires, flathead, looks slightly dropped in front maybe a reversed eye spring.
It looks like an early hollow wooden paddle board/surfboard, often referred to as a, "cigar box". In an effort to reduce weight in the 30's Tom Blake, plus many others started to experiment by making hollow boards. They were usually around 13'-14' and finless. This was long before anybody started building a foam/fiberglass board or even a balsa wood board.
\ @J.Ukrop Hello, Many years ago, our dad took us to a very small rental in Newport Beach. We lived in a small Westside of Long Beach house, but this one was smaller, yet. (The term beach cottage is a good description) But, it was at the beach and a few steps away was the sand and ocean. So, it was a vacation. There is a section of Newport Bay right on the water that my wife and I looked at smaller homes. The area had access to a waterfront dock available for our sailboat. But, at the time, the houses were very small and the cost of the homes far surpassed our allowances. The boat slip was nice and private, but rented by someone in a week after we saw it. Our old high school wood shop had plans for making a long wooden paddleboard. But, since we had access to two already made, we wanted to make surfboards, which was not allowed. The photo shows a paddleboard that is hollow. It has a flat deck and the bottom could be flat or curved, depending on how the builder shaped and glued the wood. We paddled around the Belmont Shore Alamitos Bay area on a couple of flat top paddleboards as teens. It was a nice way to go deep in the middle of the bay or skim close to shore for the friends laying around on the sandy beach. But, as we paddled, we had to be farther back as the flat bottom dug into the water. So, if we were too far forward, the nose dug into the water surface, we went slower and sometimes, fell overboard. The normal position for early paddleboards, shown below. If one had bad knees, then a sit down position with a paddle was the mode of the day. But, the very early models were used as surfboards on the waves along the California coastline. Without a fin, too! Point into the shoulder of the wave, paddle to get in the wave and the weight of the board allowed the person to ride the wave to shore. No fancy cutbacks or bottom turns, as is the modern surfboard with fin design allows, but a straight forward movement across the face of the wave. Jnaki Assuming the roadster is around 12 feet long, the surfboard looks to be around 14-15 feet. “Spring Break at Balboa Island in 1938, back when they still called it “Easter Vacation.” At that time, the break was always scheduled to occur the week leading up to Easter Sunday, regardless of how late in the school year it fell.” The original photo was taken by Rex Hardy for LIFE Magazine.
Probably a surf board. The old school longboards can be up to 14 ft long. It looks like it may have been broken, split down the middle where two pieces of wood were joined together, that's probably why it doesn't taper on the side shown. Maybe that's crusty wood glue on the face we can see.
Bingo, Just what @El Hueso and @jnaki said. I've got the book about Tom, "Tom Blake: The Uncommon Journey of a Pioneer Waterman". Tom had a couple hot cars back in the day. Here's a picture of Tom with one his his boards similar to the one in the roadster. Here's a picture from the book of Tom and his roadster.
In the mid 50's in San Diego these paddle boards were commonly used by abalone divers and the like. They were hollow and on the top behind the solid wood nose there was a hole placed used to empty the water out after it's use. The hole plug was a common cork thermos plug. They were bulky long and carrying them was like wrestling a pig in the mud. Great work!