Mike Richards measures a FAST 40+ for an Endorsed certificate. Photos: James Boyd Measuring One-offs
Obviously one-off, custom builds require a significant amount of measurement. Perhaps the most time-consuming part is taking draft measurement, this being a two-stage process. First with the boat out of the water, the lowest part of the keel is measured up to two known points, such as a stanchion base and/or a chainplate, using a laser or tape measure. The boat is then relaunched and measurements are taken from the same two ‘known’ points to the water level. The latter figures are subtracted from the former and the result averaged to calculate draft.
“It’s very simple – it just takes a while to set it up out of the water,” declares Mike Richards. He has been getting to practise this repeatedly in recent months, measuring FAST 40+s to ensure they are within the Class 3m maximum draft limit. “Everybody’s pushing that quite hard, so we have to be pretty careful. But generally for IRC we don’t measure draft that often unless it is for a new prototype.”
Boat weight measurement is relatively straightforward. Richards works closely with the local boatyard, Hamble Yacht Services, which has a crane that will lift up to eight tonnes. The boat is put in slings and then onto chains, which hook up to a central point attached to a load cell. To ensure consistency, in the UK load cells are provided by the RORC Rating Office and come in a variety of sizes depending on the weight of the boat (e.g. 7.5, 12 and 20 tonnes). For larger boats, bigger load cells are available, and other methods of measuring boat weight are sometimes accepted for very heavy boats.
Richards continues: “Then we try to find out exactly how much fluid is on board. Usually there’s no water, but there’s often some diesel in the tanks.” The weight of the fluid and that of the strops/chains are subtracted from the load cell reading to determine the boat’s overall weight.
Usually owners believe their boat is heavier than it is, and that can be a difficult thing when the weighing result does not match expectations. But this is not always the case. “We had one big issue with a FAST 40+ whose owner thought it was much lighter than it was. When we actually weighed the boat in all its constituent parts we found the keel fin was considerably heavier than the designer had declared.” This can also occur with production boats, where the first few are built to exacting standards which are subsequently relaxed.
Rig and Overhangs
Although the sail measurements are mostly taken at the loft, the measurer must still obtain standard rig dimensions such as J (base of foretriangle), STL (spinnaker tack length), P (maximum hoist point of the mainsail on the mast), FL (forestay length), etc. Typically these dimensions are recorded by tape measure, a two-person job with one up the rig and another on deck.
“Then we do the overhangs,” Richards explains. “We hang a plumbline off the bow and measure back to where the waterline intersects with the bow.”
This is simple provided the boat isn’t one with a ‘flying knuckle’ or classic curved bow. “Then we also have to do a few more measurements to work out where the 45° point is to measure the ‘x’ and ‘h’ as well as the forward overhang,” continues Richards.
Part of the measurement of the stern overhang is to find the height of the corner of the transom above the waterline (y). “It’s a really simple measurement, and to be honest most people can do it themselves. All we do is ensure the number is as accurate as possible, so you’ve got to make sure there are not too many waves and not too much wind.”
Typically to measure a boat fully for IRC takes just over half a day, but often with a bit of organisation and forward planning it can be simplified. “One morning, we did six Sun Fast 3200s and 3600s. They all turned up and we just ripped through them,” Richards recalls. He hopes to take this a step further. “I’m working with Hamble Yacht Services to hold some measuring weekends. At present yards don’t tend to measure boats on the weekends. That means people have to take time off work to do it. But we’re going to try to change that so people can have their boats measured in their leisure time.”
Spot Checks
Thanks to the simplicity of IRC and its measurement, cheating, Mike Richards says, is something of a rarity. “At regattas we’ve found sails that are big, but that’s the worst I’ve come across.”
However, measurers do get brought in at regattas to carry out spot checks, especially on boats that are doing well. “For events like the Swan Europeans there are certain sails, particularly in the Swan 45 class, you have to check,” observes Richards. “For the FAST 40+s I also do some spot checking on sail sizes. With the IRC Europeans in the Solent next year there will certainly be spot checking and measuring taking place prior to the event.”
In a nutshell, IRC measurement applies to the minority and is nothing sinister, nor too difficult, time-consuming or expensive.
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