Carrying Your Dinghy: Davits, Swim Platform Mounts and Safe Towing

Look for a rating label on the davit arms, the base or the platform brackets, or look it up in the maker's manual by model. Write the number down. Some makers rate the pair, some rate each arm, and some give a lower limit when the boat is underway than at anchor. If you can't find any rating, treat the system as unknown and have a rigger or surveyor look at it before you trust it.

Add up the dinghy, the outboard, the fuel tank, oars, pump, anchor and anything else that rides in it. A small scale and some arithmetic work: weigh yourself, then weigh yourself holding the item. Then allow for water: a gallon of water weighs roughly 8 pounds, so a few inches of rain in the bottom can add more than the outboard. Soundings' advice is to go for overkill because the real load is always heavier than the brochure weight.

Davit ratings are usually for a straight vertical lift. Underway, the boat rolls and pitches and slings the dinghy side to side, which puts big sideways and twisting loads on the arms and mounts. If most of the weight (the outboard end) hangs from one arm, that arm takes more than half. This is why a davit that holds the dinghy fine at the dock can bend or crack its mount offshore.

Do this every season, and after any rough passage:

• Arms and welds: look for bends, cracks at welds and bases, and rust bleeding from stainless joints.
• Mounting bolts and bases: check they're tight (no rocking when you push the arm) and that the sealant isn't cracked. Rust streaks or wet core around a bolt mean water is getting in.
• Inside the transom or deck: with a flashlight, look for backing plates under each base. Soundings recommends wide, heavy stainless or aluminum plates, and warns that cored decks often aren't strong enough to mount davits at all. Spider cracks in the gelcoat around a base are a sign the structure is flexing.
• Lifting gear: blocks, sheaves, falls (lifting lines) and hooks. Replace chafed or sun-faded line and any block that binds. Shackles should be the right size and have their pins secured.
• Power davits or hydraulic platforms: follow the maker's service schedule for fluid, hoses and seals.

Check the chocks or snap brackets for cracks and loose fasteners, and look at the platform brackets where they bolt to the transom. A platform that sags at the outer edge, or brackets with cracked gelcoat around them, is overloaded. Owners often find the platform needs reinforcing once a dinghy and outboard live there: ask the boat builder or a surveyor before adding weight.

• Lift with the bow slightly higher than the stern so rain drains aft and out the transom drain (pull the drain plug while it hangs, and tie the plug to the dinghy so it's there when you launch).
• Lift high enough that a following sea can't slap into it, but not so high that it makes the big boat tippy.
• Lift quickly and smoothly so the dinghy doesn't bang into the transom. Keep hands and feet clear of the falls and blocks.

Hanging from the falls alone isn't enough underway. Run straps (or stainless wire with turnbuckles, which stretches less than rope) from the dinghy to fixed points on the davits or transom so it can't swing side to side or fore and aft. Recheck the lashings after the first hour and after rough water. On a platform mount, make sure every latch or strap is locked before you get underway. Once it's up, pull the dinghy's drain plug so rain and spray can't collect.

Check your lights and numbers with the dinghy up. Soundings points out that a dinghy carried upright on swim-platform davits can hide the stern light and the boat's name. Look from astern at night: if the white stern light can't be seen across its full arc behind you, the light needs to move (ask a marine electrician) or the dinghy has to ride differently. The same goes for an inflatable carried on the foredeck or in the cockpit: it must not block the navigation lights or your view ahead.

Tow only for short, protected runs in good weather with a forecast that stays good. BoatUS's insurance files show towed dinghies swamping, flipping and breaking loose, so for any longer run, open water, or a forecast with wind, get the dinghy up on the davits or the deck. Never tow on long passages.

Take out everything loose: oars, cushions, life jackets, pump, fuel can. Put the drain plug in tight. Take the outboard off and stow it on the big boat if you can. BoatUS notes a 60-pound motor adds a lot of drag, strains the dinghy's transom and fittings, and turns into a projectile if things get rough. If the motor must stay on, tilt it fully up, lash the powerhead to both sides so it can't flop, attach a safety cable in case the clamps back out, and remove the fuel tank.

A single painter on one bow ring is only OK for a very short tow with a hard dinghy that tracks well and has a low towing eye on the stem. For everything else, especially inflatables, rig a bridle:

• Tie a line between the dinghy's two bow D-rings so it forms a triangle a few feet ahead of the bow.
• Pass that bridle through a bowline (or a small block) on the end of the towline so it can slide and share the load between both rings.
• Do the same at the big boat's stern, leading to two cleats.
• Slip a small float on the towline near the big boat so the line floats and stays out of the prop.
• Some inflatable makers suggest leading two lines from the stronger transom towing rings, under the hull, crossing at the bow eye, then to the yacht's cleats. Check your dinghy maker's advice.

Tie off the bitter end of the towline to a second strong point, as BoatUS suggests, in case a cleat hitch slips.

There's no single right length. For a sailboat or trawler at about 8 knots or less in small waves, BoatUS's rule of thumb is to put the dinghy two wave crests back, on the downhill (front) side of the second stern wave. Then watch it:

• Swerving from side to side: shorten the line to pull it into the flat part of the wake.
• Bouncing in the prop wash: lengthen it.
• At the right length it tracks straight behind you.

Shorten the line before entering a harbor or crowded channel, and bring the dinghy alongside before docking or backing down, so the line can't reach your propeller.

Go slowly. Planing speeds put huge strain on the fittings and can launch the dinghy into the air, and BoatUS does not recommend towing at high speed based on its claims. Look back often, especially if the wind picks up. A dinghy that is taking water gets heavy fast: BoatUS points out that a few inches of water in a small inflatable means hundreds of pounds of drag on its D-rings. If it's filling, slow down and deal with it in calm water, or get it aboard.

The dinghy is a boat too. Carry a life jacket for everyone in it, a light if you'll come back after dark, and a way to call for help (a handheld VHF or a phone in a waterproof pouch).

Lights after dark: under the U.S. Inland Navigation Rules, a dinghy you row must at least have a white flashlight or lantern ready to show in time to avoid a collision. Once the outboard is running it counts as a power-driven vessel, and the Inland Rules call for red and green sidelights plus an all-round white light (battery-powered clip-on sets are sold for small boats). Rules differ slightly on international waters, so check the Navigation Rules for where you boat. A small, low dinghy is hard to see at night even when lit, so stay out of channels where you can.

If the dinghy's outboard has an engine cut-off switch, the operator must wear the lanyard: the USCG rule covers motorized boats under 26 feet with 3 hp or more.