Simple method to weigh a laser?

Lately, my performance is begin really horrible and I'm not sure of how much the bad state of my boat may be affecting.

For instance, during the last regata I discovered that my bailer is broken, so the cockpit was continuously full of water. Besides, I don't know exactly how but my battens have disappear (is it normal that they fall down accidentally?). Finally, during transportation, I had the strong feeling that my hull is much heavier than others. Yes, yes, I know what you're thinking about: I've checked it and there is no water inside.

So, apart from repairing the other things, I was wondering whether there is a simple way to weigh a laser, I mean, by just using one or two domestic balances or so. Have you any experience about that?

Pedro.

As far as i know you need only one domestic balance: put bow on the ground and soport stern with the balance, then put stern onthe ground and soport bow with the balance, add the two weights.

135630 said:

As far as i know you need only one domestic balance: put bow on the ground and soport stern with the balance, then put stern onthe ground and soport bow with the balance, add the two weights.

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Hi,
this is a correct method. Keep attention, that in total only 2 points (Bow and stern, but not additional a side of the hull) have contact to the ground.

Ciao
LooserLu
(Civil Engineer, MoS)

Really simple: I will try and compare to other boats.

Thanks a lot!

Just wanted to interject something:

Keep in mind that if you have one end on the ground with the other on the scale, your boat will be inclined. It seems to me that the low side will feel more weight and the opposite for the high side. In other words, your boat might measure lighter than it actually is. For most accuracy, block the end of the boat without the scale so that the tops of the blocks and the scale are level.

I don't know how much it would change anything, but it surely doesn't take much effort to throw a block under the boat to be sure.

XtSurfMogulXt said:

... It seems to me that the low side will feel more weight and the opposite for the high side. In other words, your boat might measure lighter than it actually is. ...

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In theory: the boat gets two components of forces. The vertical ones and an additional horizontal force. It's the same theory like an engineer (1st lesson in static calculations) describes the forces of a 1-field-bridge. The horizontal force not has influence to the results of measuring the weight of the boat, if the domestic-balance stands correct in horizontal level. Then, the domestic-balance does show only the vertical force, that is the half of the total weight of the boat (, if the position of the balance allways is at the end of the hull of the boat).

XtSurfMogulXt said:

... For most accuracy, block the end of the boat without the scale so that the tops of the blocks and the scale are level. ...

Click to expand...

There is no need to do it in that way, in reason the domestic-balance does only show the vertical force (if the domestic-balance stands correct in horizontal level).

The horizontal force grows with the growing angle in that the boat goes out of the horizontal level, but the vertical component only IS the weight of the boat. So, there is a point, the forces of friction cannot hold the boat (or the 1-field-beam of a bridge) and the boat ( / the beam) moves downwards, then one need a "fixed-support" at one end (of the beam, that is rigid connected to this "fixed-support").


You can have a little practical lesson by proving this with a ruler: Lay the ends of the ruler on your forefingers and move one of your forefingers up (or down). At one point, the ruler moves down to the earth, in reason of what I said before. To prove my words, you can use two balances for envelopes instead of your forefingers.

[For the experts: One additional point is important, I guess: the gravitaion-index "g", on our globe, not everywhere is the same. In general it is: g= 9,81 meter per square-second. We usually read at the scale of a scientific balance with "Newton", because we measure a force.
I'm allways irritated, if the not-constant "g" has a big influence to the weight the balance shows to us at the scale, if we compare a measurement that is done f.e. Mexico related to a measurement that is done f.e. Sweden ... never mind ....]


Ciao
LooserLu