The dinghy spec for our family of six — and the four constraints that killed the obvious choices

Six people in a dinghy is two trips, an overload, or a different dinghy than the one you thought you wanted.

I have been writing this number on the back of legal pads for nine months. Two adults plus four kids — born 2021, 2022, 2024, and 2025. The youngest will be in a life jacket and on a lap. The oldest will be old enough to grip a handhold and complain about it. Total weight, on the day everyone is dry and clean: 470 pounds of people, give or take. Add groceries from the dock at Marsh Harbour, a five-gallon jerry can, a snorkel kit each, and the propane tank we are bringing back from the marina — and the working capacity of our dinghy on the worst day is somewhere north of 750 pounds. Best-day, dive-with-the-kids, leave-the-jerry-can capacity: still over 600.

That number is the boat-buyer's secret. Most articles about cruising tenders are written around the dinghy itself — the brand, the hypalon-vs-PVC argument, the 9.9 versus 15 horsepower question. Those are real questions. They are also the second, third, and fourth questions. The first one is what do you do every day, with how many people, in what kind of water — and I kept finding that the obvious answers in the catamaran-tender market did not actually solve our problem.

Four constraints killed the dinghies I assumed I would buy. Here are the constraints, the boats they killed, and what I am specifying instead.

Constraint one: the davits weigh more than the brochures imply

Production cruising cats — Lagoon, Fountaine Pajot, Leopard, the lower end of the Bali line — ship with aft davits rated between 350 and 450 pounds. Outremer and the higher-end performance cats sometimes spec better, but the 50-foot family cat we are researching has a 400-pound rating on the factory davits, and the broker for the Saba 50 I keep looking at quotes the same number.

Four hundred pounds sounds like a lot. It is not.

The math on a 12-foot aluminum-hull RIB with a 25-horse four-stroke:

• Hull and tubes: 165 pounds (Highfield CL360 ALU)
• 25hp Yamaha F25 four-stroke: 126 pounds
• Six-gallon portable fuel tank, full: 50 pounds
• Anchor, rode, oars, lights, painter, kill-switch lanyard: 25 pounds
• Total: 366 pounds

That is a nine-percent margin against a 400-pound davit rating. Nine percent margin for the fuel sloshing, for the spray load, for the dynamic load when the cat pitches in a swell at anchor. Engineers do not ship nine percent of margin into a system that holds 366 pounds of expensive metal over a teak transom and four sleeping children. Engineers ship 30 percent.

The boats that died from this constraint:

Highfield CL400 ALU (13'1"): 200 pounds dry. With a 30-horse Yamaha F30, total wet weight is over 430 pounds. Past the rating before the fuel is in. I wanted this dinghy. The aluminum hull is the right answer for a tropical cruiser. The 30-horse pushes plane with five people aboard. None of it matters if the davits cannot carry it.

OC Tenders 12' Sport: a beautiful fiberglass-hulled RIB that runs dry in chop, holds six adults, and prices around $14,500 before the engine. Hull weight: 220 pounds. Same problem. Plus the OC is a console boat, and the console adds another 40 pounds.

The fix is either to upgrade the davits — real money, since Garhauer makes a 600-pound system for around $4,200, and installed it is another $2,500 in labor and reinforcing — or to keep the dinghy under 165 pounds dry. I am keeping the dinghy under 165 pounds. The reinforced-davit money is going elsewhere.

Constraint two: the boat you want is not the boat you can beach

The second constraint is unsexy and it is the one nobody writes about. A family of six does not stay aboard. The kids want sand. The grocery store is a half-mile walk from a beach. The water taxi at Hopetown drops you at the public dock, not the resort dock, and the public dock has a tide.

Which means I need to land a dinghy on a beach, in surf, with a 14-month-old in arms and a four-year-old who has decided this is the moment she is afraid of the water. The dinghy needs to pull up onto sand without damaging the prop, take a wave on the transom without swamping, be light enough that I can drag it up the beach single-handed while my wife handles the kids, and have a fiberglass or aluminum bottom. A fabric-bottom roll-up is a five-year boat in a coral fringe.

The brand that died here was the Walker Bay Generation 360 with the air floor. The air floor packs down small, it stores in a locker, it is light. It is also a fabric bottom that I would put a hole in by the third beach landing in Eleuthera. Roll-up dinghies are the right answer for the boat owner who tenders mostly to docks. They are the wrong answer for a family that beaches the dinghy four times a week for a year.

A small note on this — and one of the few moments I will let my own boat into the post — when we sea-trialed a Lagoon 46 in St. Martin two winters ago, the broker's tender was a Highfield with an aluminum hull, and I watched him run it bow-first onto a coral fringe, drag it up two feet, and walk away. I want to do that.

Constraint three: the outboard you can lift is not the outboard you wanted

Mounting and dismounting an outboard is the dinghy-ownership task that ages a cruiser. You will do it for storage. You will do it for service. You will do it the first time the kicker swallows water and you have to take the cowl off in the cockpit.

Anything over about 130 pounds is a two-person lift on a moving deck. The numbers I checked:

• Yamaha F20 (twin-cyl, 20hp four-stroke): 117 pounds
• Yamaha F25 (twin-cyl, 25hp four-stroke): 126 pounds
• Tohatsu MFS25 (25hp four-stroke): 130 pounds
• Suzuki DF25 (25hp four-stroke): 159 pounds
• Mercury F25 EFI: 135 pounds
• Yamaha F30 (30hp four-stroke): 137 pounds

The Suzuki DF25 is widely considered the best 25-horse in the market for fuel-injection reliability and ease of service. It is also the heaviest. It is the outboard I cannot lift onto the rail single-handed in the dark when my wife is below with a sick kid.

That ruled out the Suzuki. It also ruled out the Honda BF20, which at 110 pounds is the lightest but uses a carburetor that hates ethanol fuel — and Bahamian gas stations are not famous for ethanol-free pumps. The Yamaha F20 and Tohatsu MFS20 are the dark horses. Twenty horsepower will not plane a fully-loaded six-person RIB. But it will push it through chop at hull speed, and it will start every time, and one person can take it off the rail.

This is where I am compromising. I will trade the planing speed for the lifting weight. I will buy the F20 and accept that the trip from the cat to shore takes seven minutes instead of four. Seven minutes does not matter. A back injury at year two does.

Constraint four: stowage when the dinghy is not in the davits

This is the one I worked out last. The first ocean passage we make — Bermuda to the Azores, sometime in 2028 — the dinghy is coming off the davits. It always does. Anything pendant on the back of a cat in serious weather is a snatch waiting to happen. The Pardeys took dinghies off davits. Behan Gifford takes hers off. The catamaran-davit failure rate in heavy weather is a real number nobody publishes.

So: where does it go? Three options on a 50-foot cat. Inverted on the foredeck, lashed to the trampoline frame — standard practice, but it requires a dinghy under 11 feet to clear the headsail tracks, which eliminates the big tenders entirely. Strapped vertical to the aft cockpit bulkhead, blocking the swim platform access — awful for any anchorage stop on the passage, reduces aft visibility for the helm, and real cruisers do this and complain about it. Or deflated and lashed in the aft locker — only works for a roll-up or a folding tender, and we ruled out roll-ups in constraint two.

Which brings me to the dinghy I am actually specifying: an 11-foot aluminum-hull RIB with an outboard I can lift, sized to fit inverted on the foredeck for ocean passages.

The two boats on my short list:

Highfield Classic 340 FRP — 11'2", 156 pounds, aluminum hull and removable transom, rated for 6 persons and 25hp. List around $5,800 in the configuration I want.

AB Mares 11 VST — 11'9", 138 pounds, hypalon tubes over an aluminum hull, rated for 6 persons and 25hp. List around $7,200.

Both fit inverted on the foredeck of a 50-foot cat with a 25-foot beam. Both can hold our family on a good day. Both will beach. The AB has the better tube material for the tropics — Orca CSM (hypalon) versus the Highfield's PVC — and the resale on AB is famously strong. The Highfield is $1,400 cheaper, and the resale is fine.

I am going to buy the AB. The tube material is what dies in tropical sun, and I do not want to replace tubes in year four. Even on a five-year plan, the AB pays back the difference in UV protection.

Total spec, written in the order I am committing to: AB Mares 11 VST with hypalon tubes, aluminum hull, console-less for kid-wrangling room. Yamaha F20 four-stroke, electric start, remote tiller. Two six-gallon portable fuel tanks (one in use, one as reserve). No davit upgrade — stay under the factory rating with margin. Total commissioned cost runs about $11,800.

That is the boat. That is the engine. That is the answer that survived the four constraints.

The compromise I did not want to make

A 20-horse will not plane this boat with six aboard. The planing speed with two adults and four kids is around 12 knots — a touch under hull speed for an 11-foot RIB, comfortable in light chop, slow in heavy chop. The boat will get on plane with two adults and one kid. That is roughly the ratio of trips we will make. Most days the dinghy is two of us going for groceries, or me taking the older two out to a reef. The all-six trip is the Sunday-afternoon trip to the beach.

I considered going to the 25-horse and lifting the F25 in two pieces — leg off the powerhead, two trips, two minutes each. I tried that on a friend's boat in the Sea of Cortez last spring. The split-lift is doable. It is also the kind of thing that gets done less and less as the cruise wears on, until one day it is not done at all, and the back goes out reaching for the third lift of the morning.

I would rather be slow than be hurt. The F20 it is.

What changes if I am wrong

Two things would change my answer.

First — if we end up on a boat with a larger davit rating. A Lagoon 55 with the upgraded davit package is rated to 600 pounds. On that boat the math reopens, and the OC Tenders 12' Sport comes back on the table. Better dinghy, better seating for the kids, better ride in chop. The bigger boat opens the bigger dinghy. One reason the boat-length conversation never ends.

Second — if the kids prove they can climb back into a dinghy from the water without help. They cannot now. They might at six. When they can, the constraint loosens, and the safety case for the outboard kill-switch and the slow-plane F20 weakens. Old-timer cruisers run 30-horse RIBs because they are running adults around. We are not. Yet.

For now: AB Mares 11, Yamaha F20, hypalon over aluminum, on the factory davits with margin. The dinghy worksheet has been the easiest of the 47 to write — and the one I have had to redo three times before I trusted the answer.