Although there already are exercise machines that simulate nordic skiing, rowing and other activities, they're usually separate devices that are all fairly large. Whipr takes a different approach, consisting of a small base unit that works with multiple attachments.
The system was invented by marine biologist/scuba diver/stand-up paddler Luke Tipple, who needed a way of exercising in hotel rooms while on the road.
Measuring about 6 inches (152 mm) per side and weighing 6.7 lb (2.7 kg), its cube-shaped base unit contains a planetary gearbox, a magnetic resistance wheel, and a 10-ft (3-m) pull cord with a metal ring on the end. That ring allows users to clip on peripherals such as a stand-up paddleboard-type paddle, a couple of overhead pulley-routed handles that are held like cross-country ski poles, and a rowing handle that's used with a seat that slides along a rail.
After users dial in the desired amount of resistance, they secure the base unit in place. This is done using either a webbing strap that's simply slung around an unmovable object (such as a fence post), or by using the integrated "inflatable anchor." The latter is basically a flap that gets inserted under the bottom of a closed door, then inflated on the other side of that door by repeatedly pressing a pump button on the main device.
From there, users just start pulling on the peripheral. As they do so, a screen on the base unit displays metrics such as strokes per minute, total repetitions, and calories burned – the exact metrics to be displayed have yet to be determined.
Should you be interested, Whipr is currently the subject of a Kickstarter campaign. Assuming it reaches production, a pledge of US$199 will get you a base unit, with an additional $70 required for the paddling or skiing attachment, and $120 for the rowing attachment. Other accessories, based around other activities, are in the works.
The system is demonstrated in the following video.
Sources: Kickstarter, Whipr