Sizing a lift is a boat problem first and a lake-permit problem second. This guide keeps them apart. Nothing here is a manufacturer’s capacity table. Those belong to the company that built the lift, and the research behind this site did not collect a set we are willing to republish as if we had tested it.
Size the lift from the boat
- Length and beam, measured, not remembered from the listing.
- Dry weight from the boat’s capacity plate or the builder’s spec sheet.
- The weight you add: fuel, water, coolers, a tower if it was an option, and the gear that stays on the boat all summer.
- The hull the bunks have to match. A pontoon and a deep-V wake boat do not sit on the same bunks.
- A PWC is its own smaller lift. Do not put a jet ski on a “it will probably be fine” corner of a boat lift and call that a plan.
The lift you buy or reuse needs a readable capacity that covers that working weight, with the margin the lift manufacturer specifies. If the plate is gone, the lift is not sized. It is a guess. Say that on the used lift request instead of inventing a number.
Cable and strap vertical lifts, hydraulic lifts, and PWC lifts are different machines. Name the one you have or the one you think you want. The builder can disagree from the photos. That disagreement is cheaper than the wrong steel.
Where Ameren lets the lift sit
Appendix B, section 6.13, as revised June 30, 2025:
- A boat lift must be attached to a permitted dock.
- Stand-alone lifts are not allowed.
- A lift cannot be anchored to the lake bed.
- Fixed lifts on the lake bed are also barred next to piers.
- Lifts and accessories use materials that are safe in the water.
- They may not be arranged to enclose or fence in water for private use, and they may not block safe navigation. Ameren can refuse an attachment that hurts a neighbor or navigation.
Setbacks, for residential docks of 10 slips or fewer:
- The dock itself sits at least 5 feet inside the side property line extended into the lake.
- A slip, external lift, or accessory 15 feet or longer, placed parallel to the shore, is set back at least one and a half times its length.
- The same kind of attachment shorter than 15 feet, parallel to the shore, is set back at least one times its length.
- A lift attached perpendicular to the shore stays at least 5 feet inside the extended side line.
A lift that sticks out to “catch the deeper water” is the attachment that fails these lines. Put the slip dimensions and a photo in the installation request.
The bolt rule is about the foam
Section 7.5 says flotation is attached with 3/8-inch minimum plated bolts, thick fender washers, and lock nuts. Outside J-bolts are prohibited. That rule keeps floats on the dock. It is not a boat-lift assembly drawing. It still matters when you add a lift, because the lift is dead load and the floats have to carry it. Under dead load, Ameren wants at least 7 inches of freeboard under the frame. A new lift on a dock that is already low is a refoam conversation.
When the lift changes the permit
Ameren’s $550 fee covers a new dock or a modification. Adding a lift that changes wells, width, flotation, or the setback is a modification, and construction waits for the permit. Dropping a new motor on a lift that is already inside a permitted well may not be. Do not guess in the direction that lets you start welding. Describe the before and after. The builder, or you as the owner, is who submits the packet. This website does not.
Slip length is capped at 55 feet for residential permits. A lift does not create permission for a longer boat to hang out past the mouth of a slip permitted after March 30, 2008. Appendix B says watercraft in those slips shall not extend beyond the mouth.
What to send
Boat type, length, and the weight source you used. Photos of the stern and of the slip. Town, cove, mile marker. Whether the dock permit is in your name. If you are pricing only, say so. The cost page explains why there is no dollar table next to this one.