More Than You Want to Know about Dinghies.

It is an absolute rule of the ocean: All boats are compromises. None are perfect. That rule goes double, or triple (at least) for dinghies.

Forty years ago, before inflatable boats were reliable and popular, almost every cruising boat had a hard dinghy stored on deck. Eventually, inflatable dingies became the choice for most yachts because they were… well… de-flatable. They collapsed into a small package that could be stuffed into a cockpit locker safely out of the way.

Our old dinghy was a great tool, and at a great price, but the PVC construction limited its lifespan.

The introduction and popularization of the Rigid Hull Inflatable Boat (RIB) changed that calculus a lot. The RIB offered a much better performing boat, and one that stood up to everyday wear-and-tear much better than its fabric bottomed ancestors. Soon most cruising boats that could handle a RIB, had one. The downside was the dinghy, once again, required storage space on deck.

Like every sailor we have a list of things that we wanted our ship’s dinghy to be. Unfortunately, there is no boat that could ever meet all of our requirements. Our dinghy must be big, and compact. Tough, and soft. Lightweight, and strong. Well built and inexpensive. We wanted more durablity, but we didn’t want to give up the compact storage. We wanted a boat with a drier ride in rough water, but we didn’t want to add a lot of weight. We wanted a boat that was compatable with our existing 15HP motor.

You get the idea. This article is not a recommendation for a specific product because every sailor will have a slightly different mix of priorities that might produce a different result. We had to decide which side of the various compromises involved we would have to come down on.

In the past couple of years we have spent a lot of time in our dinghy, and in other people’s dinghies. We have learned what is possible, and what is important for us, what is nice to have, and what we wanted to avoid.

I would guess that at least half the time we launch our dinghy we end up hauling it up a beach. So something not too heavy, and with a tough bottom was very high on our list of gotta-haves. This is doubly import for those time we are landing or launching in any significant surf. Having a boat you can easily hold into the waves by hand, and then quickly board is critical. We crossed off all dinghies with inflatable or roll-up floors. Having a rubber fabric bottom was just not compatible with landing on a coral beach. That left us with either a hull of aluminum or fiberglass.

Even soft sand beaches can be tough on fabric bottom boats, while sharp coral rocks can be instant disaster.

We did consider a hard bottom, non-inflatable dinghy. Unfortunately none we know of checked enough of our boxes to enter the final selection process, so we stayed on the conventional track of an inflatable.

The rigid part of the hull is almost always either aluminum or fiberglass. Aluminum is (usually) lighter and tougher, fiberglass is cheaper. Some manufacturers have had problems with keeping the tubes glued to aluminum hulls over the long term, while others seem to have solved this problem. Aluminum comes either painted or plain. Painting aluminum seems an un-needed addition. If the proper aluminum alloy is chosen, paint is not needed for protection. No matter how well done, the paint has a finite lifespan. Once a paint job begins to fail, it looks worse than the bare metal hull ever will.

Both aluminum and fiberglass are pretty tough materials, and are very unlikely to be catastrophically damaged. Fiberglass is more susceptable to wear, and some people argue that it is easier to repair. But I can slap a fiberglass patch on an aluminum hull with not much more effort than I would need to patch a fiberglass hull, so I counted that as a wash. On severe impact, fiberglass is more likely to crack or crush, while aluminum (usually) just bends.

A RIB can be constructed with either a flat deck on the inside of the boat, or it can mirror the V-shape of the outside of the hull. Far better is the flat deck. It raises anything you put into the boat up out of any water sloshing around, and makes for far better footing when boarding the dinghy. The older we get, the more important that easy footing becomes. The brand we ended up with makes both, and surprisingly they are the same weight. The extra metal needed for the flat floor is offset by using lighter metal everywhere, and a more sophisticated and expensive system of bracing.

We considered the flat floor almost essential, and the bow locker a “nice to have” place to keep the fuel tank, life jackets, and other safety gear.

The importance of weight is an issue that is frequently misunderstood. People assume that the reason for light weight is to make the dinghy easy to load onto the mothership. This is actually a minor consideration. Pretty much any sailboat has mechanical tools in the form of halyards and winches that allow two people to handle the weight of any reasonably practical dinghy. The REAL importance of weight comes when you are landing on a sandy beach and you need to quickly drag the boat up out of the surf zone. A dinghy that weighs much over 100 lbs (BEFORE motor, fuel, etc) is a challenge in this situation for the average cruising couple.

Lifting a dinghy up on deck, even one well over 100 lbs, is pretty simple with a standard sailing winch and free halyard.

We decided an aluminum hull RIB would be the best fit for us. That meant no folding, and also meant we would need to store the dinghy on deck, all the time. That meant the dinghy would be exposed to sunlight, all the time. That precluded any with PVC tubes. We very quickly decided that the rubber/neoprene/fabric construction frequently known as Hypalon (a Dupont trademark) and generically known as “CSM” was going to be needed.

Speaking of the inflatable tubes, one of the significant differences between dinghies is the diameter of the tubes. They make a huge difference in the way a dinghy performs and feels to its passengers. As an example, the 9’6″ boats we were looking at are built with tubes 15, 16 or 17 inches in diameter. That might seem a small change, but it is not. When you are using a dinghy with 15 inch tubes you feel like you are sitting ON the boat. In rough water you will be getting quite wet from spray. A similar boat with 17 inch tubes feels very different. It gives the impression of being IN the boat with a more significant barrier between passenger and the elements. The boat give a much dryer ride, and is much more stable.

Deciding on size is a tough choice. Bigger is better, until it comes to pulling the dinghy up the beach on a rough surf day, or finding a good storage spot on deck. Once we made the decision to go with a non-folding RIB, the size choice was going to be dictated by where the dinghy could fit. Any deck mounted boat has three problems that must be addressed. Visibility, access, and security.

One of the great things about the folding design of our old dinghy was that it fit on deck in a very compact package. We knew that duplicating this was not likely to be possible.

Visibility from the helm station is obviously important. The dinghy should not create large blind spots that are problematic when docking, or allow other vessels to approach unseen. We have been unhappy with visibility for most arrangements we have seen on boats like ours with dinghies mounted forward of the mast. Some dinghies mounted upside down on the foredeck do have acceptable visibility profiles, but working out an elegant tie-down system that is strong, and doesn’t compromise access to the foredeck can be difficult.

Access to all parts of the deck is important in both routine and emergency situations. We were pretty sure that we were going to end up with a dinghy stored on the deck aft of the mizzen mast, so we needed to be sure that we would still have easy, safe access to the stern of the boat.

Lastly is security of the dinghy in a seaway. For us davits are just not an option. For bay or coastal sailing this really isn’t much of an issue, but crossing oceans is a very different matter. Until you have been in REALLY rough water it is hard to imagine the force of a wave washing across the deck. I saw one posting online in which the author confidently proclaimed that sailing with a dinghy hanging on davits was fine. He had an Island Packet 38 with a high freeboard, and couldn’t imagine a wave big enough to overwash his deck. I guess he had never heard that the Queen Elizebeth II had windows—75 feet above her waterline!!!—broken by a wave in the North Atlantic. Mother Nature really doesn’t care if you can imagine how nasty she can get. While in Newport we saw a boat come into the harbor that had a wave poop it’s davit-mounted dinghy while returning from Block Island. The back of the boat was a tangled mess of twisted metal.

Measurements are great, and they are a necessary start. But really being sure how such a complex three-dimensional shape will fit and interact with the deck of the boat is a challenge. We were very lucky that we had another Amel Super Maramu pull in next to us who had a dinghy of the exact size and shape we were looking at stored on their aft deck. Our conclusion was that it wasn’t the most elegant arrangement, but it was fully functional, and we’d have no problem with moving around it. A compromise, but one we were happy with.

Harmonie with the dinghy stowed on the aft deck. It doesn’t do much for me esthetically, but it seems, for us, to be the best answer.

Some boats have mounted their dinghy on a cradle on the fore deck that holds the boat upright. Like Delos:

The arrangement on S/V Delos for their dinghy.

There are a lot of reasons I do not like this. Having the dinghy upright means that it can fill with water. Even with the drain plug out, it would take a VERY long time to drain out the TON of water (yes, literally 1000 kg/2000 lbs) of water that a large wave could dump there. Is this likely to happen? No, not at all. However, it most certainly CAN. The stability of the yacht itself in this case would be seriously compromised, and the chances of the tie down system being about to hold that much weight is not good.