So you've read on some blog or other about Laser sailing and decided it sounds like fun. You went down to watch your local Laser fleet racing and saw people of all ages, sizes and genders out racing Lasers, and now you're certain that Laser sailing is for you. But you're nor sure whether you need to buy a Standard Rig or a Radial Rig... or even something called a 4.7 whatever that is.
Well let me try and explain. Basically it all depends on your weight.
When the Laser was first launched over 35 years ago it came with one size of sail. It quickly became very popular, but over the years it became apparent that for lighter people, especially smaller women and younger teenagers, it was more than they could handle in a real blow. It was clear that a smaller, less powerful rig was needed for the boat to become popular with lighter people.
One attempt to solve this problem was called the M-rig. It never really caught on. If you see one for sale I don't recommend you buy it. There are very few of them around and you won't find any other M-rigs to race against.
The real breakthrough in solving the issue of making the boat more manageable for lightweight sailors was the Laser Radial. This uses a shorter more flexible bottom mast section and a radial cut sail with 18% less area than the standard rig. The Radial is now immensely popular for youth and women's racing. Indeed the Radial is the single-handed boat for women in the Olympic games.
It was then discovered that many kids who learned to sail in Optimists and aspired to sail Lasers had a problem. There was a weight range when they were really too heavy for an Optimist but not quite heavy enough for a Laser Radial. So the Laser 4.7 Rig was introduced. This uses a shorter pre-bent mast section and a sail with an area of 4.7 square meters, smaller again than the Radial sail.
So now we have the Laser range....
The Laser 4.7 which suits sailors who weigh roughly 75 to 120 lbs.
The Laser Radial for sailors who weigh 120 to 155 lbs.
The Standard Laser for sailors who weigh over 150 lbs.
Of course these are not hard and fast rules. Any sailor, however light they are, can sail a Standard Rig Laser in very light winds. But as the wind picks up a lightweight will find it harder to keep the boat flat and when it gets very windy they will be so overpowered that they will be capsizing way too often for it to be fun any more.
Also skill level and fitness make a huge difference. A young fit expert sailor of 130 lbs would probably be faster than a heavy, clumsy old doofus like me in a Standard Rig, even in heavy weather.
Some sailors own Radial and Standard Rigs and switch according to the conditions. In light winds they sail the Standard Rig; then on a day with a real blow they sail the Radial. The hull and almost all the equipment is the same. All you need to change is the sail and the bottom half of the mast.
One caveat. At least in North America, the 4.7 rig has been positioned as being for kids transitioning from Optimists to the Laser. The major regattas for 4.7 rigs are for juniors only. So if you are an adult weighing 110 or 115 lbs say, I would advise going with the Radial, not the 4.7. You won't find other adults to race against in the 4.7. (Of course you could always buy a 4.7 rig as well so you can go out and practice and have fun when it's blowing dogs off chains if you want.)