What Size Davit Do I Need? Sizing by Loaded Weight

Sizing davits comes down to one number, and it is not your boat’s length — it’s what the boat actually weighs sitting in your canal with fuel, water, and gear aboard. Get that number right and davits are a clean, low-footprint way to lift a light boat out of the salt. Get it wrong and you’re the neighbor with a bent arm and a strap on the bottom of the canal.

Here’s how to size davits honestly in Southwest Florida — how to find your real loaded weight, how it maps to a davit’s rating, and the cases where the right answer is a lift instead.

What weight do I actually size davits to?

Size davits to your boat’s fully-loaded weight — hull plus engine, a full tank of fuel, water, batteries, and gear — never the dry number on the brochure. That loaded figure is what the davits lift every single time.

Build the number up from the hull:

• Hull — the manufacturer’s dry or published weight (read the fine print; some include the engine and some don’t)
• Engine — an outboard, especially a heavier four-stroke, adds real weight that dry specs often leave out
• Fuel — gasoline runs about 6 pounds per gallon, so even a modest tank adds up quickly
• Water — a livewell or freshwater tank; water is heavier than fuel, roughly 8 pounds per gallon
• Everything else — batteries, an anchor and rode, a cooler, tackle, and the gear you leave aboard

Add it up and a “light” boat is often hundreds of pounds heavier than the spec sheet suggests. That total — not the length, not the dry weight — is the load your davits carry.

What’s a davit’s working load, and how does it relate to my boat?

Davits are sold with a rated working load — the weight the pair is built to raise and hold safely. Your fully-loaded boat has to sit comfortably under that rating, with margin to spare, not right at the line.

Davits typically come as a bow-and-stern pair that share the load, and the rating describes what the set carries together. The goal is to match your loaded weight to that capacity and leave a real cushion, so the davits never run at the edge — which matters even more in salt water, where every fastener, cable, and strap is already working hard against corrosion. Online calculators can’t see your boat or your wall, so we confirm the exact rating, strap setup, and mounting on site. If davits are the right tool but you’re mounting to a wall, our seawall davits guide covers the install side.

Why does undersizing davits fail — fast — in salt and wind?

Undersized davits run overloaded on every lift, and Southwest Florida’s salt and wind punish that harder than calm freshwater ever would. Overload plus corrosion plus sway is how arms bend and straps let go.

• Salt is already attacking every fastener, cable, and strap; an overloaded davit has no reserve when a corroded part is quietly weaker than its spec
• Wind makes a hanging boat sway, and that shock-loads the arms beyond the boat’s static weight — a gust does more than the number on paper
• Cycling — every raise and lower — fatigues an over-stressed arm faster than an under-worked one

Undersizing to save a little money is the most expensive mistake you can make here, because when a davit fails it usually takes the boat with it. It’s the same wind-sway problem we cover in boat davits vs. a boat lift — margin is what protects you.

When is the honest answer “get a lift instead”?

When your loaded weight is near or past what davits comfortably carry — think center consoles, bay boats, and cruisers — stop forcing davits and put in a four-post cradle lift.

Davits top out light by design. A loaded center console or bay boat belongs on a four-post lift that spreads the weight across four pilings and cradles the hull on bunks instead of hanging it from two straps. The same goes for a boat that lives in the wind or one you run most days — a cradle holds it steady and shrugs off the cycling. Our companion guide walks the full lift-sizing math in what size boat lift do I need. For a personal watercraft, skip davits entirely for a purpose-built jet-ski lift.

How do you confirm the right davit size?

On site. We weigh the real-world variables — your boat fully loaded, your seawall or dock, your canal and its wind exposure — and spec davits, or a lift, that carry the load with margin for years of salt and surge.

The safe number is the loaded number, and the only way to nail it is a look at your actual boat and waterfront. Florida Lifts & Docks has sized lifts and davit setups across Southwest Florida since 2008 with our own local crew, never subbed. See everything we build on our boat lifts page, book a free on-site estimate in Cape Coral or anywhere on the coast, or call (239) 397-3400 and we’ll get you a real answer.