SWAMPSCOTT — A unique vessel can be spotted off the shore of Fisherman’s Beach this week.

The Seismic Princess is being used by the town to test sand density for a potential $20 million pier project. The boat utilizes its “feet” to press into the sea floor and elevate its “body” out of the water so its passengers do not have to deal with the sea’s motion.

“What it does is it gets you out of the tidal work zone,” Fitzgerald Metal Works owner Dave Fitzgerald said. “You can get above any tides that go up and down.”

Fitzgerald’s company was responsible for the design and construction of the rig now being used by McAllister Marine Engineering, which has been hired by the town to carry out the pier’s redevelopment. The sand-density testing is one portion of the project’s first phase, which is known as feasibility research.

Harbor and Waterfront Advisory Committee Chair Jackson Schultz emphasized the importance of the testing, as it will determine what materials would be most appropriate to use for the pier’s construction. Drills have been attached to the Seismic Princess, and the density is measured in 6-inch intervals through the amount of hammer blows to the drill casing it takes to penetrate through the ground.

“You take these blow counts and that gives you a good picture of the density of the soils that you’re going through,” McAllister Marine Engineering founder John McAllister said.

He added that samples of the sediment will be sent for laboratory tests to determine more specific physical characteristics. According to McAllister, the depth of bedrock layers tends to vary significantly in the ocean. Therefore, it is crucial to identify the different depths.

“The ideal is you’re finding dense soils that are densely compacted,” McAllister said. “The deck needs to be constantly supported, it needs to carry all the weight. If there’s cars, people, whatever there is… all that load is transferred down to the bottom of the piles like it is on a foundation in your house.”

The town recently received a grant of $212,800 from the Seaport Economic Council with the goal of getting 60% of the design phase complete. The first phase of the project was funded through a $100,000 grant from the SEC as well. Schultz said that the new pier might not be completed until 2030.