The second-largest owner of U.S. marinas is acquiring the third-largest owner, creating a new powerhouse in this niche real-estate business as boat sales surge during the pandemic. Centerbridge Partners LP said it is paying about $400 million for Westrec Marinas, which the investment firm will absorb into its own Suntex Marinas. That will create a combined company with more than 50 marinas that is valued at $2.5 billion, making it the second-highest-valued U.S. marina owner after Safe Harbor Marinas.