Aspen C90

Aspen builds power PROA catamarans that combine rugged construction, finely finished interiors and pleasant accommodations with a unique ultra-efficient smooth riding hull form.

After selling Glacier Bay, which he previously founded, Larry Graf designed and patented a unique PROA cat hull and launched Aspen Power Catamarans.

Each hull has a similar exterior shape and length, but one is 35% thinner, meaning there’s less resistance and it requires less power. Models like the C90 and C100 use a single inboard diesel. The larger hull houses the engine, a keel, prop and rudder while the other is unencumbered. Propulsion on one side doesn’t make the boat turn, as hydrodynamics ensure straight tracking. The narrow entry of the hulls slices easily through the water, providing smooth, even acceleration and top speeds nearing 25 mph, even though they don’t plane. Fuel efficiency and stability are added benefits, giving Aspens good range and sea-keeping abilities. To prove it, Larry and his son, Nick, took an Aspen C90 664 miles around Vancouver Island, unrefueled. They averaged 13.6 mph, burned 267 gallons of diesel (with expedition tanks) and completed the journey in 47 hours.

When driving an Aspen, the slippery nature of the hulls is apparent, as they make little wake and coast slightly with pulled-back throttles. Underway you can barely tell each hull is different, they track evenly in both directions, although slightly different trim tab settings work best.

Having grown up boating on Lake Michigan, I wondered how Aspens would do in the Great Lakes, where tighter wave periods, the density of freshwater and rapidly changing weather affect boating. I contacted some Aspen owners in the Midwest to find out how the unique design of Aspen Power Catamarans works for them in the Great Lakes.

Fits the equation

Jeff and Joanne purchased their Aspen C90 Sea Tiger in 2020. The C90 has the same configuration as the C100, except the latter has a hull and deck 4 feet longer in the cockpit. Jeff now has two seasons of cruising under his belt; however, when he first bought the boat, he was a relative newcomer to recreational boating. His previous boating experience was aboard a Navy submarine in his youth, after which he became an engineer and analyst.

All of this contributes to his amazingly methodical, detailed approach to boating. Before he purchased the Aspen, he developed a set of criteria to match prospective boats to his aspirations of one day completing the Great Loop. Fuel efficiency, speed and displacement meant diesel power. He also required a boat with modest draft, bridge clearance under 19.5 feet and one that could be easily single-handed. Other important factors were creature comforts because he planned to spend long periods aboard the boat. When Jeff entered Aspen into his spreadsheet, he had a winner; the C90 has everything he wanted, including sturdy construction, quality systems and comfortable accommodations. His Aspen has a roomy salon, a fully appointed galley, two sleeping cabins and a head with a shower.

Concerned about close quarter handling, he found that the Aspen is highly maneuverable. To back into a narrow slip, he turns the rudder then easily backs and fills with small bursts of the bow and stern thrusters.

Jeff’s meticulous analysis of boating and cruising is impressive. He analyzes weather patterns using a variety of data and apps, creating a “Go vs. No Go Chart” to help plan passages by predicting conditions. This is particularly important for lake crossings, as it ensures the safety and comfort of the vessel and occupants. Avoiding bad conditions is important but, eventually, we all get caught in weather.

I asked Jeff how the Aspen handled extreme conditions. Sea Tiger is based in Michigan on Lake St. Clair, which means he often traverses either the St. Clair River north to Lake Huron or the Detroit River south to Lake Erie. Cruising north, he described a passage under the Bluewater Bridge near Sarnia. The river bends sharply, with one side U.S. and the other Canada. This passage is heavily trafficked by large commercial vessels, and Jeff relates how the AIS system on his Garmin MFD keeps track of them when he can’t see around bends. A funneling effect creates currents reaching 6 knots, and wind against the current means steep chop. In the strong eddies, even large trawlers get thrown around, but the higher speed and ample rudder of the Aspen keep him on track. Running at 15-20 mph, the stability of the cat helps him cut through the waves and maintain safe passage. Small boats often fish the channels near bridges, and because the Aspen throws little wake, Jeff keeps power on for better control without endangering them.

In steep 7- to 8-foot waves at a 3- to 4-second period, he found angling the boat to the waves and tacking at 45 degrees improved the motion and allowed the Aspen to crest the waves, cutting through them and gliding down the backs without undue slapping. The Aspen’s tunnel is designed to cut through waves, and the tacking technique is only necessary when things get extreme. Jeff says that the formidable construction of the Aspen is apparent in adverse conditions as the boat feels solid and remains controlled.

Jeff enjoys that his Aspen outperforms other boats. When running 95 miles in Lake Huron from Port Sanilac to Harrisville, he averaged 7.2 gph cruising into head seas at around 20 mph (3400 RPM) and soundly beat another boat on the same leg. Jeff plans to extend his exploration by heading further into Canadian waters, which will hopefully remain open next summer. Georgian Bay, the North Channel and Sault Ste. Marie are on his list, with the Great Loop still on the horizon.

Winning over buyers

Owners of the Aspen C90 Graceful, Laurent and Erica, chose Aspen for several pragmatic reasons. Erica (Laurent admits it is her boat) was skeptical at first about catamarans, but a few things won her over. Visibility from the helm and the salon is excellent, even for someone of her short stature. The stability in Aspen’s 10-foot beam means it does not roll like other boats, which they and their dog, OB, appreciate. Both owners like the king-size bed, which is not a V-berth, and that the head is outside the owner’s suite; the C90 head can be accessed from the salon so guests don’t enter their cabin.

As avid land campers, they like the amenities, storage and utility of the boat. Efficiency, performance and the ability to haul the boat themselves on the trailer all are important. Laurent and Erica plan to cruise further east on Lake Erie next summer and possibly through the canals as far as Rochester on Lake Ontario.

Input from enthusiastic Aspen owners I spoke with confirmed that Aspen Power Catamarans work well in the Great Lakes. The Aspen C90 combines the performance and efficiency of its PROA cat design with the kinds of amenities boaters want. In addition, the boat’s stability and toughness allows it to travel safely, even in the occasionally challenging Great Lakes conditions.