PS Advisor: 07/01/05
Is there a correct way of towing an inflatable dinghy? Some say it should be towed a short distance behind the boat, while others say always pull the dinghy partly out of the water, attached to the stern rail. What do you advise?
Thomas R. Baker
There are several variables to consider when determining the optimum approach to towing an inflatable dinghy. First, these craft do vary in size and shape, and second, the configuration of your boat's transom (or transoms in the case of multihulls) has to be factored in as well. And remember, towing a dinghy isn't something you do when transiting open, unprotected waters, though you see sailors doing this all the time. Towing should be reserved for those brief passages made in relatively smooth sea conditions, otherwise the boat should go on deck, or in davits. We once lost a perfectly nice Dyer Dhow dinghy while towing it downwind in moderate seas—roughly five feet from peak to trough. That's a lesson you only want to endure once.
Presuming that you're asking about a small, say 9- to 11-foot tender, we've always favored getting the boat right up next to the transom of the mothership for towing, with the bow of the tender raised slightly out of the water. This approach effectively makes the dinghy part of the larger craft for maneuvering. The real advantage of this approach is that, with such a short painter, the line will be under constant strain, so the dinghy will be less likely to react to waves and wind and won't surge up on a wave or bump against the hull of the larger boat, thereby sparing both vessels the damage that action would cause.
Of course, if you tow the dinghy in this fashion, you'll want to make sure that it's not adjacent the engine's exhaust port. And you'll want to keep an eye on your painter from time to time to ensure that the wear and tear isn't excessive. Also, be sure that the painter is attached to a secure portion of the dinghy. Most inflatable manufacturers prescribe towing their boats by using specific attachment points on those boats, and most inflatables have a bridle that spreads the load. It's also a good idea to use a second tow line run through the bridle and back to an eyebolt on the dinghy's transom, particularly if you'll be towing it for long distances or at night.
We didn't mention it, because it should go without saying, but it's important to remove all loose items from a dinghy—like bailers, pumps, life jackets and gas cans, etc.—before you get underway. It’s all right to stow the oars on board a dinghy that will be towed if they can be secured, but we advise against towing your dinghy with its outboard motor in place. Again, many sailors do this, but they risk immersing the engine, so it should be done only for short distances in reliably smooth water.
Some sailors will advise you not to tow the dinghy so close to the mothership. Instead, they favor trailing it well astern. If you opt for this method, it's prudent to keep the dinghy far enough astern so that it "parks" on the front of the second wave in your wake. To determine that distance, you simply get the mother ship up to its cruising speed, and then begin easing out the painter until the dinghy sits comfortably with its bow slightly inclined on that second wave.
We're looking for a good dinghy to use. There are a lot of them, and many seem a bit extreme. Are there any guidelines for stablility and performance for boats that are to be rowed or propelled by a small outboard?
By a coincidence, a book in its fourth edition and originally assembled in 1978 by Ian Nicholson contains the data you seem to want. The book ($30) is "The Boat Data Book," published by Sheridan House Inc., (www.sheridanhouse.com). Nicholson is a widely-known British writer of nautical tomes. He constructed a chart showing what he views as sound relationships between length, waterline, beam, draft and freeboard at 1/4, 1/2 and 3/4 LWL. In general, the freeboard at the bow should be at least 115% of the freeboard at half LWL and the freeboard at the stern should be at least 85% of the freeboard at half LWL.