In short
- Lift size comes from loaded weight, not the brochure dry weight: add engines, fuel, water, batteries and gear.
- Gasoline is about 6.1 lb per gallon, fresh water 8.34 lb per gallon, and a marine battery about 40 to 75 lb.
- Add a margin, commonly 15 to 20%, and round up to the next lift size.
- Check beam against the lift's inside width, and have a licensed contractor or engineer check what the seawall and pilings can carry.
On this page
- How the lift size is worked out in four steps
- Weights this page uses
- Common lift sizes and the loaded weight each can take at 20% margin
- Capacity is not the only thing that has to fit
- Questions to ask a marine contractor about a lift
- Next step: get an engineer or contractor to confirm
- Sources
- Frequently asked questions
This boat lift capacity calculator is for Cape Coral boat owners who are choosing or replacing a lift on a canal. It adds up everything the lift has to hold, adds a safety margin and rounds up to the next common lift rating. It uses weights only, with no prices. It supports our Cape Coral boat lift permit checklist.
En español: calculadora de capacidad de elevador de botes en Cape Coral
| Your numbers | Result |
|---|
Example: a 24 ft center console with the engine in the dry weight, a 70 gallon gasoline tank, no fresh water, 2 batteries at 60 lb and 300 lb of gear.
How the lift size is worked out in four steps
- Start with dry weight
Take the builder's number and check whether it includes the engines. If not, add them.
- Add what goes aboard
Full fuel tank, fresh water, batteries, gear, and anything left aboard when the lift raises.
- Add the margin
Multiply the loaded weight by 1.10 to 1.25. The default is 1.20.
- Round up
Pick the next lift rating at or above that number. Never round down to a smaller size.
Weights this page uses
| Item | Weight |
|---|---|
| Gasoline | about 6.1 lb per gallon |
| Fresh water | 8.34 lb per gallon |
| Marine battery, lead-acid | about 40 to 75 lb (default 60) |
| Safety margin | 15 to 20% common (default 20%) |
Fuel weight differs a little with grade and ethanol, from about 6.0 to 6.3 lb per gallon, so 6.1 is a working value. Saltwater is heavier than fresh, about 8.55 lb per gallon, if you carry any in a live well or ballast.
Common lift sizes and the loaded weight each can take at 20% margin
| Lift rating | Loaded boat up to |
|---|---|
| 4,500 lb | 3,750 lb |
| 6,000 lb | 5,000 lb |
| 7,000 lb | 5,833 lb |
| 8,000 lb | 6,667 lb |
| 10,000 lb | 8,333 lb |
| 13,000 lb | 10,833 lb |
| 16,000 lb | 13,333 lb |
| 20,000 lb | 16,667 lb |
| 24,000 lb | 20,000 lb |
These sizes are a typical ladder. Each maker sells its own set of ratings, so a model may be rated 4,400, 5,000 or 15,000 lb instead. Use the rating on the maker's sheet.
Check the wall before you add a lift. A lift loads the seawall, cap and any pilings with the boat, the lift itself, and wind and wave forces. A licensed contractor or engineer should confirm what your structure can carry before you buy. See building near a seawall: loads and setbacks and the boat lift permit checklist.
Capacity is not the only thing that has to fit
- Beam. Measure the widest point including rub rails and swim platforms. The lift's inside width needs to clear it with room to spare.
- Hull length and shape. Bunks or a cradle have to match your hull, and deep-V boats and pontoons need different supports.
- Engine drop. Outboards and drives set how high the lift must raise and where the weight sits.
- Weight balance. Heavy engines put the load toward the stern. Ask where the lift's cradle puts the support.
- Canal width and setbacks. The city sets how far a lift may project. See the permit checklist.
Questions to ask a marine contractor about a lift
- What loaded weight did you size for? Ask to see the numbers, not just the rating.
- What does the wall or piling have to carry? Ask who checks it and whether that is in writing.
- Is the lift engineered for Cape Coral? The city asks for the lift's engineering specifications with the permit.
- Who files the permit and the electrical permit? See seawall permits in Cape Coral.
- Does your wall warranty cover lift loads? Many exclude drilling the cap or adding a lift support. See the warranty guide.
Next step: get an engineer or contractor to confirm
This result is a planning estimate, not an engineering design. We are a referral service, not a contractor; we connect visitors with independent local providers. Use the form below to ask independent marine and seawall contractors about your lift and wall.
Sources
- Hewitt, How to Size a Boat Lift Correctly: dry weight plus fuel, people and gear, water and batteries, and a 20% margin.
- Boat Blurb, What You Need to Know About Gasoline: regular gasoline about 6.1 lb per gallon.
- BoatCalculators fuel and water weight: fresh water 8.34 lb and seawater about 8.55 lb per gallon.
- Renogy, How Much Does a Marine Battery Weigh: typical battery weights by group size.
- ShoreStation capacity models: one maker's pairing of lift capacity and inside width.
Frequently asked questions
How do I figure out what size boat lift I need?
Add up the loaded weight of the boat: dry weight, engines if they are not included, a full fuel tank, fresh water, batteries and the gear you leave aboard. Add a safety margin, commonly 15 to 20 percent, then round up to the next lift size the maker offers. The calculator does these steps.
Should I use dry weight or wet weight to size a boat lift?
Use the loaded (wet) weight. Dry weight is the bare boat as listed by the builder, and it often leaves out engines, fuel, water, batteries and gear. A lift is rated for the whole load it will hold.
How much safety margin should I add to a boat lift?
Many dealers and manufacturers suggest at least 20 percent, and some accept 10 to 15 percent. The extra covers weights you forgot, water in the bilge or a wet hull, and gear you add later. Saltwater, heavy chop and a boat you expect to load up are reasons for the higher end.
How much does fuel weigh in a boat?
Gasoline is about 6.1 pounds per gallon and fresh water is 8.34 pounds per gallon. Diesel is heavier than gasoline, about 7 pounds per gallon. A full 70 gallon gas tank is about 430 pounds. The calculator assumes a full tank, since that is the heaviest case.
Does a boat lift need a seawall or pile check?
Yes. A lift puts the boat's weight, plus the lift's own weight and wind and wave loads, on the seawall, caps or pilings it attaches to. Ask a licensed contractor or engineer to check what your wall and structure can carry before you buy a lift. Cape Coral also requires a permit and engineering for the lift itself.
Is the lift's rating the same as the boat's weight?
No. The rating is the most the lift is designed to hold, and you want the loaded boat to sit comfortably below it. A boat at 100 percent of the rating has no margin for fuel, rain, or a wet hull.