Category Archives: Measurement

How They Weigh a One Metre ?

Leave a reply

When you come into Radio Sailing, you hear a lot about weights. It’s a hot topic, just like it is in dinghy and keelboat racing.

As an aside : when I ordered a new Dragon keelboat, I remember going to the builder (who had lots of Olympic golds, world titles and the rest of it) and asking what weight he thought the boat would come out at. He said 1700kg is the rule. I naturally asked, “Yes, but what weight do you think you can build mine to?”… “1700kg” came the reply. And he did. Amazing.

So in at least One Metres and Marbleheads, owners and builders have the same keen interest in weights as my Dragon Builder.

I was keen to see my new IOM weighed. The photo above shows the setup. A digital scale with fine graduations plus a wooden IOM standing bracket. Easy enough to see how the Measurer does his job now.

In fact, here is my boat being weighed. Note hatches and onboard battery are inside the weight limit.

Thinking of my Dragon story above, I thought you’d be interested to see how accurate my IOM builder was. “He’s 21Gms over!”, you proclaim !!

Well, I thought that too, so I asked him. I take it that lots of people do. I received a well practiced answer. He says that they target 20gms over because they find that scales around championships do vary. So if you weigh in at a Championship and it looks like you are 20gms over, you can always pop the corrector out.

OK – so he was 1gram over !!….

How Will My Sails Get Measured??

Leave a reply

So got your new boat? Have your sails been measured and certified?

Check first at the tack of each sail and see if bears a Measurer’s mark or signature? If it has a signature, it will have been measured in. If not, think about getting it done.

Datchet Radio Sailing have the measuring process well sorted. In the workshop, there is a giant board maybe a couple of metres long – see photo above.

I’d half expected when watching the measuring process, that the big rulers would come out and key measurements recorded for all your rigs. It was much cleverer and faster though.

The Measurer had a collection of pre-marked half dowels. So it was very fast for him to run the dowel rods over key dimensions of each sail – check if the sail measurements were within prescribed limits, ….and we were done in no time.

Ever Seen Your Boat Being Measured ??

Leave a reply

If you’ve bought yourself a nice second hand boat to start, to get your race certificate sent off to the super class registrar at MYA and get it transferred to your name.

But what if you need to get measured? Got a new boat maybe? Got a boat without a certificate? Well, find yourself a qualified measurer – we have two at Datchet Radio Sailing.

A lot of us, even as newcomers, will have IOMs. I was fascinated as a newcomer to hear that there are tanks or boxes for the measurement process. Do you know what they look like? The one above is just being filled with water.

If your builder supplies a compliance certificate for the hull, then the main work is measuring the rigs. Interestingly, to get your certificate your boat need not go in the tank. However, be aware that when you measure in at a Championship, a tank test might be needed. So if someone offers you a test now, my recommendation is accept the offer straight away and see what is going on.

My understanding is that here are basically four tests the measurer look for.

1/Does it float freely in the tank, which I believe is an overall length test.

2/ You can check the fore and aft trim easily… move your correctors about for your desired trim. Is this measurement or just what you’d want? Im not sure. Someone will write in and tell me.

3/ Does it float -a depth test

4/There is a cunning window on the side of the tank to see how much draught the hull is taking. See that black line? I think the hull has to float above it. (Again if I am wrong, please write in!!)

Fascinating. If you are offered a tank test, take it!!