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Old 27-11-2012, 01:41 PM   #1
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Boat make: Hydrostream V-king, 650SS OCR ,Ring 21, Ring 18, Phantom 18.
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Weighing you boat on its trailer.

Little formula Ive found for weighing your boat on its trailer!

Put a scale under the nose of the trailer/ jockey wheel and record the weight (W1), slide the boat back by a measured amount (X), record the nose weight on the trailer (W2). Measure the distance from the ballance point on the trailer/axle to the point you placed the scale (C).

W1 = first (heavier) scale reading in lbs, W2 = second scale reading in
lbs, X = the distance you shifted the boat in inches, C = distance between
trailer axle and scale point in inches.

The formula is Boat Weight = C (W1-W2)/X

Note, this will only work for single axle trailers, can use it on twin axle trailers if you take one pair of wheels off!

Just thought people might be interested in it!
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Old 27-11-2012, 01:52 PM   #2
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Nice one.
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Old 24-10-2013, 01:56 PM   #3
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Country: In the UK, in an offfice, looking out the window at the rain.
Occupation: Chartered Engineer
Interests: boats, water, snow, football
Boat name: DoubleSix
Boat make: Ring 21c
Engines: Opti 200
Cruising area: Lyme Bay

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Quote:
Originally Posted by Hydrostream View Post
Little formula Ive found for weighing your boat on its trailer!

Put a scale under the nose of the trailer/ jockey wheel and record the weight (W1), slide the boat back by a measured amount (X), record the nose weight on the trailer (W2). Measure the distance from the ballance point on the trailer/axle to the point you placed the scale (C).

W1 = first (heavier) scale reading in lbs, W2 = second scale reading in
lbs, X = the distance you shifted the boat in inches, C = distance between
trailer axle and scale point in inches.

The formula is Boat Weight = C (W1-W2)/X

Note, this will only work for single axle trailers, can use it on twin axle trailers if you take one pair of wheels off!

Just thought people might be interested in it!
This is really good. Going back through the Technical Q&A this question comes up with predictable regularity. I am as much a culprit as anyone else having asked the question only a month ago!

I am an engineer by profession and am a little embarrassed that I didn't think of this myself. But I have been through it and checked the theory and the maths. Even the weight of the trailer doesn't need to be considered even though you are weighing it, it only returns the weight of the boat and engine (i.e. all the bits that you move forwards or backwards)!

So, This is bumped back to the top for everyone's convenience; and if anyone finds the maths difficult (brackets and all that), I have created a little spreadsheet that will do it all for you. It has a labelled diagram, you just have to type in some numbers and it doesn't even matter which measurement you take first - and then move the boat forwards, or backwards.

PM me if you'd like a copy.
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Old 24-10-2013, 07:48 PM   #4
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Or put some scrap metal in the boat take it to your local metal recycling yard and they will weigh it for you on the way out
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Old 25-10-2013, 08:33 AM   #5
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Country: In the UK, in an offfice, looking out the window at the rain.
Occupation: Chartered Engineer
Interests: boats, water, snow, football
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Boat make: Ring 21c
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Cruising area: Lyme Bay

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Or put some scrap metal in the boat take it to your local metal recycling yard and they will weigh it for you on the way out
According to this forum there are a lot of people with Scrap metal already attached to the back of their boats.
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Old 25-10-2013, 09:34 AM   #6
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What's the going rate for Jap aluminium?
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Old 25-10-2013, 11:08 AM   #7
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Country: Ireland
Location: Dublin
Occupation: Boatbuilder
Boat make: Hydrostream V-king, 650SS OCR ,Ring 21, Ring 18, Phantom 18.
Engines: 300Hp Mercury 2.4, 130 Yamaha, Bridgeport EFI, XR6, Merc 200.
Cruising area: Malahide, Dublin

Join Date: May 2004
Location: Dublin
Posts: 1,803
Quote:
Originally Posted by Marinautic View Post
What's the going rate for Jap aluminium?
Seems I have a lot more american ali than any other!
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