Wolverine Insurance Company has introduced updates to its Michigan watercraft program, filing new rate and rule manuals on May 4, 2026, with an effective date of August 1, 2026 for both new and renewal business.

The program covers 607 policyholders and approximately $222,976 in written premium.

Instead of pricing changes, the update centers on a full refresh of rating and underwriting rules across both standard boats and yachts, replacing prior manuals from 2022.

The revised program maintains a traditional inland marine structure, with premiums driven by base rates, territory, coverage levels, and a wide set of credits and surcharges tied to risk characteristics such as boat type, age, ownership structure, and operator experience.

Key underwriting constraints remain in place. The program excludes high-risk segments such as boats exceeding 40 feet, speeds above 65 mph, values above $200,000, commercial use, and certain specialty or nonstandard vessels.

Coverage continues to include physical damage, liability, medical payments, and optional features like uninsured boaters coverage, pollution liability, and agreed value endorsements, with additional enhancements for towing, equipment, and emergency services.

The filing also reinforces the use of insurance scores and motor vehicle records in underwriting, linking boating risk to driving behavior and applying tiered discounts based on credit-based insurance scores.