The Tender Trap
How much does a yacht tender weigh, and how big a tender can fit upon a swim platform? The rule is to pick a tender that’s at least 2 feet shorter than the beam of the mothership. That leaves enough clearance for docking misadventures without damaging the tender. At least with any luck. So, an express cruiser with a 14-foot beam— the Monte Carlo 5, for example—should carry a tender that’s 12 feet or less on the platform.
The true limiting factor, however, is weight, not length. The Monte Carlo’s submersible platform is rated for about 770 pounds. That’s capacity aplenty for an outboard-powered RIB. AB Inflatables’s Nautilus 11 DLX (11-foot LOA x 5-foot 10-inch beam) weighs 440 pounds. Add a 111-pound, 20-horsepower Yamaha outboard and some gear and it’s still under the limit. And there are many nice RIB tenders that weigh less than the Nautilus, and don’t need as large a motor.
Of course, it’s easier to launch and retrieve a jet-drive like the Ribjet 10 Sport tender. You can just submerge the platform and drive the boat on and off. The 10 Sport weighs 570 pounds dry, including the 60-horsepower Rotax jet package. I figure with fuel, PFDs, anchor, and other gear we’re at 650 pounds. Still OK.
But what about a PWC? A typical model can weigh 700 or 800 pounds. For instance, Yamaha’s 10-foot 3-inch Waverunner EX weighs 577 pounds, and the 11-foot Waverunner VX weighs 708 pounds. Both weights are dry, so add as much as 100 pounds more for full gas tanks. The EX makes the cut, but the VX is too heavy. (Note that the nominal platform weight limits include a very big safety factor three or four times what may be necessary, and sometimes more), but we recommend going by the book.
When planning to add a submersible platform with the intention of carrying a tender, don’t just see if it’ll fit on the platform. Take into account total weight, too. And even on calm days, always cover the tender and remove the plug to keep out sea and rainwater. Water is heavy, and a half-full RIB will overstress the platform in short order. In rough weather, it’s often smarter to tow the thing.