Safety is really what we're talking about when asking the question of what is a properly sized boat for the lake. Being tossed about due to rough water isn't fun and certainly not safe. Over the years the solution has been a steady increase in the size of boats being purchased. Throughout its existence boat sizes on the Lake of the Ozarks has been an arms race of sorts with boats seemingly getting larger every year. In the 1960's my father's 18ft Mark Twain was considered a good size boat and got around just fine. In the 70s he purchased a 22ft Sea Ray that provided a decent ride, but immediately regretted not buying the 24 footer. After the 80s (thanks "Miami Vice") a boat needed to be in the +30ft range if you wanted to go fast and smooth as the proliferation of very large (+40ft) and slow cruisers meant a dramatic increase in the size of waves. Larger boats mean larger waves, and larger waves means boat owners buy larger boats, with the vicious cycle continuing to this day. Still, you don't need a 38ft Cigarette or 35ft Donzi to enjoy the lake, but it helps. The question of how big of a boat is big enough to handle the Lake of the Ozarks has no simple answer but depends on many factors such as pilot experience and skill, time of year, type of boat, desired running speed, and number of passengers.
Pilot skills: The Lake of the Ozarks attracts different kinds of boaters, from rank novice to race experienced experts, and while any boat can be piloted safely even in the worst conditions, not all pilots have the skills to pull it off. Likewise, a large boat under the control of an inexperienced pilot is no guarantee of safety or comfort. If you have a relatively small boat (<30ft), on a busy weekend, a novice pilot can easily get themselves into trouble and hurt someone, while an experienced one can make it safe and relatively comfortable.
Time of year: From mid-September to early May boat size is mostly irrelevant as the lake remains calm with room to maneuver and roll through the occasional big wake. In the summer however weekends can be relentlessly rough with congestion making it difficult to smooth wakes out over distance. Holiday weekends even more so. My definition of a properly sized boat is one that doesn't cause injury to passengers just because it is underway at cruising speed. The lake can be rough, but it needn't be dangerous if boat size matches desired boating style.
Style of Boat:
Fishing boats, less than 26ft in length, are often flat bottomed and at no time in the summer, except in the early hours or weekdays, is it comfortable to be making speed on the lake in one. Small fishing boats in calm coves are common enough but are well advised to stay away from the main channel.
Pontoon boats are popular for their ability to carry many passengers comfortably, but are relatively slow and struggle in rough water if not equipped with a middle pontoon ("tri-toon") and a properly sized motor. A 24ft pontoon with only a 60HP motor may be fine on Lake St.Louis, but at the Lake of the Ozarks it is a bit under powered, and will likely run into difficulty on busy weekends in the main channel. For a period of time, "deck" boats were replacing pontoons as the barge of choice but developments in pontoon/tritoon design and open cockpit style runabouts have long since passed them over.
Large cruisers, 40 feet or more rarely have any concerns over rough water to worry about regardless of speed, which is usually under 30kts. Bigger is better, but it causes issues for others. Large boat owners need to be cognizant of the severe wakes their boats are capable of putting out and the damage they can do.
A runabout, which can range from 16ft to 40ft is where speed becomes a critical factor. Assuming a boat in this size range is capable of getting on plane (the very definition of a runabout), how well it can handle rough water is mostly dependent on pilot experience and speed.
Speed: If you want to go fast (+50mph) on the weekends, you're going to need a bigger boat. I have a 27ft Sea Ray Pachanga capable of +60mph but wouldn't dare to try and get that kind of speed out of it during the weekend except in short bursts, it is simply too small. While the boat itself may be able to take the beating (it is a Sea Ray after all!), my passengers cannot. I've been in a 31ft boat that did just fine at that speed but most mono-hull boats running +50mph on the weekend need to be at least 33ft long or above in order to make good speed in the rough waters of the main channel.
Passengers: Many boat owners don't stop to think about passenger comfort too much. If the boat ride isn't too rough on the pilot, then passengers should be fine, right? Wrong. Pilots have the advantage of seeing wave impacts coming and control over how they are attacked, with one hand on the wheel, and another on the throttle(s) they have added support and leverage to resist heavy impacts or rapid directional changes. Passengers on the other hand are mostly left to holding on to anything they can grab onto (including each other) and usually unable to see or pay attention to oncoming waves and brace themselves properly.
Don't overload your boat! Cramming your boat with more people than its carrying capacity allows is illegal and usually a recipe for disaster. Even pushing the capacity can be unwise if your going out for and extended boating day. Coolers weigh a lot. More people in your boat means more cargo, and both mean more weight that can result in your boat struggling in rough conditions. To be safe, make sure you know your boat's operating capacity for specific conditions. For instance, while I can legally carry 9 passengers in my 27' boat, on a summer weekend doing so would be hard on everyone, including the boat.
Don't forget, if someone is hurt on your boat, with little exception you are required to report it to the Water Patrol.
Location: The Lake of the Ozarks is one of the largest commercial lakes in the U.S. with over 1100 miles of shoreline and over 100 miles of main channel and where you play can have a dramatic impact on water conditions and the type of boat that's enjoyable to use. Generally speaking, the first 31 miles of the main channel (starting at Bagnell Dam) are the most popular, and thereby the roughest. The state park area where Party Cove is located makes it just as busy as anywhere else on the weekends, especially the short run from the Grand Glaize Bridge to the mouth of PC. In fact, this particular three mile stretch of the Grand Glaize branch can be some of the roughest water on the lake during the weekends. Elsewhere, boaters far upriver past Hurricane Deck (above 35MM) or the Niangua River arms usually have a little less traffic, but this is offset by the narrowing of the main channel and the overall effect is virtually the same, rough water. While the lake can be rough anywhere and at anytime these outer reaches are usually a little more subdued. On the weekdays, even in the peak of summer, the lake is rarely congested and boating is very casual just about anywhere.
As for that 27ft Pachanga of mine? While it is a bit of a slog on the summer weekends to make speed, it can still handle the water with only the occasional bump or bruise, but it is certainly all the boat needed during the week. I think I'll keep it for awhile longer... or until the price comes down a bit on that 35ft Donzi I saw on eBay last week. :)
