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Old 25 March 2009, 10:21   #31
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Just reviving this thread now that I've calculated my boat weight.

I used the method quoted on another thread which involved weighing the jockey/nose weight, then shifting the boat back a few inches and re-weighing before a few calculations based on distance to axle etc. I did this a few times with different positions of the hull and they all came out at about 1150-1200kg. Add to that the trailer weight of 420kg (as stated on design plate)and we are at about 1600kg +/-.

The trailer axle is specced at 1500kg so it's safe to say the trailer is not really the right one . I assume the self-weight of the axle could be deducted but I doubt that's going to be anything like 100kgs+ so it'll still be over. If i'd bought the boat fully rigged from Osprey I'd be having words. As it was part home built, I will accept responsibility for not checking. However, it would have been nice to have been advised when trailers were discussed.
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Old 25 March 2009, 11:33   #32
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The extrapolation error in your method must be quite large - more than the 6% I would guess. I would find a weighbridge if you are concerned.

Richard
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Old 25 March 2009, 13:08   #33
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[QUOTE=Erin;287623
The trailer axle is specced at 1500kg so it's safe to say the trailer is not really the right one . [/QUOTE]

Yes, it will be heavier than 1500kg with fuel.
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Old 25 March 2009, 18:13   #34
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Originally Posted by Richard Selman View Post
The extrapolation error in your method must be quite large - more than the 6% I would guess.
Richard
I guess the fact it's not a uniformly distributed load would also affect the accuracy.

Boat had 30% fuel load, so there'd be another 100kg+ to add if fully fueled.
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Old 19 April 2011, 16:05   #35
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I was going to run a guess the weight competition, but to cut to the chase I'll save you the bother.

Moseyed up to the quarry weighbridge earlier this week and put the boat and trailer on the scales. Came out at 1620kg, which makes my earlier guestimate in this thread pretty damned accurate. This puts the boat itself with 30% fuel load at 1120kg +/-. Interesting, and not too bad compared to some quoted weights.
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Old 19 April 2011, 18:12   #36
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How much fuel was included in the 1620kg?
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Old 30 April 2011, 02:33   #37
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I think you need more rollers than that. I don't know what their capacity is but its less than a bunk and you have very little support under there right now. Both the front and rear set should be 1.5 to 2x longer IMO. Only THEN the front set extend a bit more forward on the hull. But just moving the forward set up is going to leave a huge unsupported gap in between.
+1 for a lot more rollers, but I guess the roads in Australia are nowhere near as smooth as they are over there.

I have been told by a fibreglasser friend of mine that if you don't spread the load of the boat sufficiently, over time the fibreglass gets little dimples where the rollers are. This has also been raised on the other forum I frequent offshoreonly.com which is US based and usually deals with much bigger heavier boats. Personally for the cost of rollers, I would add a few more.
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Old 21 May 2011, 15:09   #38
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I used the method quoted on another thread which involved weighing the jockey/nose weight, then shifting the boat back a few inches and re-weighing before a few calculations based on distance to axle etc.
Any chance you might be able to explain how you did this please as I'm interested to know?

Thanks.
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Old 22 May 2011, 06:00   #39
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How much fuel was included in the 1620kg?
1/3 of a tank so about 70 or 80 litres.

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Any chance you might be able to explain how you did this please as I'm interested to know?

Thanks.
see Polwart's post here
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