IOM RC Sailboats for Sale: Class Rules, Buying New or Used, and Costs
The IOM (International One Metre) is the world’s most popular radio-sailing racing class. Its rules fix the hull length at a maximum 1,000 mm, a draught of up to 420 mm and a minimum weight of 4,000 g, and allow three one-design rigs (No. 1 for light winds down to No. 3 for strong winds). Hulls must be wood or glass fibre and masts aluminium or wood, which keeps costs down and makes home building competitive. You can buy IOMs new from builders, used from racers, or as kits.
By Kyle HilsonUpdated: October 20264 min read
Key class rules
| Rule | Limit |
|---|---|
| Hull length | Max 1,000 mm |
| Draught | Max 420 mm |
| Weight | Min 4,000 g |
| Rigs | Three one-design rigs (No. 1 largest to No. 3 smallest) |
| Hull material | Wood or glass fibre |
| Spars | Aluminium or wood |
| Radio channels | Rudder and sail control |
Summary of the IOM class rules (International Radio Sailing Association class); check the current rules at iomclass.org before buying or building.
New or used?
New boats from established designers and builders are competitive straight away and come with a measurement certificate, but cost the most. Used IOMs are common because racers upgrade to new designs; a well-kept older design can still race well at club level and costs much less. Kits are another option, and home-built wooden IOMs are allowed and can be competitive. For a first IOM, a good used boat with all three rigs is often the best value.
What to check on a used IOM
- All three rigs included, sails in good shape (not stretched or creased).
- Measurement certificate, or ask the class measurer to check.
- Hull free of cracks, especially at the keel box and mast step.
- Keel fin and bulb straight; bulb weight correct.
- Rudder and sail winch work smoothly; no water damage in the radio bay.
- Spare parts and fittings included.
Costs
Besides the boat, budget for a sail winch and rudder servo if not included, a receiver and transmitter, batteries, a stand and a carry bag. Racing adds class association membership, club fees and regatta entries. Because the class limits materials, IOM racing is far cheaper than many full-size or open-class sailing options.
Getting into racing
Most racing happens at clubs with regular race days. Racers sail in fleets, often with heats and promotion/relegation, and follow the racing rules of sailing adapted for radio sailing. Ask the club if you can try a boat; many members lend boats to newcomers. Smaller classes such as the RG65 are an alternative for small ponds; see RG65 RC sailboats.
Tuning basics
An IOM is tuned through mast rake, jib and main twist, shroud tension and sail camber. Each rig has its own setup. Copy the settings of a fast boat of the same design at your club to start, then adjust for conditions. Swapping to the right rig for the wind is one of the most important race-day decisions.
Where to buy
Look at class association classifieds, club noticeboards, builders’ websites and racing forums. Buying at a regatta lets you see the boat sail. For larger non-class boats, see large RC sailboats.
Your first race day
Arrive early, ask which rig the fleet is using, and sail a few practice laps to learn the course. Keep clear of other boats at the start until you know the rules, and don’t worry about results; finishing races and learning the course matters most at first.
FAQ
What is an IOM sailboat?
A one-metre radio sailing racing class with strict rules.
How much does an IOM weigh?
At least 4,000 g.
Can I build my own IOM?
Yes; wood and glass-fibre home builds are allowed.
How many rigs does an IOM have?
Three, for different wind strengths.
More on this topic: the complete RC Boats guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
