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Old 09-21-2013
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Center of Balance

Hello everyone. New here.

I'm building a double axle trailer for a Halman 20 I just bought. I was wondering what the center of balance point measured from the tip of the prow reference would be so I can load it properly to tongue weight. It could be just ballpark. I'll nudge it around when I get it loaded.

Thanks.
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Old 09-21-2013
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Re: Center of Balance

Looks like she'll sit flat on her keel, so definitely aft of the knuckle on the cutaway, but how far back depends where the bulk of the ballast was fitted, not visible in the view below. You may need info from the designer/builder or another owner.. good luck. I'd guess somewhere in line with the main ports/windows.

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Old 09-21-2013
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Re: Center of Balance

Quote:
Originally Posted by Faster View Post
Looks like she'll sit flat on her keel, so definitely aft of the knuckle on the cutaway, but how far back depends where the bulk of the ballast was fitted, not visible in the view below. You may need info from the designer/builder or another owner.. good luck. I'd guess somewhere in line with the main ports/windows.


Thanks.

I checked the specs for the Halman and it came up with everything else but the CB.

HALMAN 20 sailboat specifications and details on sailboatdata.com

I have never seen it being hauled out and don't know where the straps were placed, and the way it sits on the old trailer is no indicator of travel load distribution. One thing I can do is build the running carriage separately and design a slide mechanism of angle iron with the spring shackles welded to it to adjust tongue load.

Haven't I heard somewhere that the CB is indicated on the side of the hull somewhere? I'm 150KM from the boat so i can't tell.

That's my problem I need to solve these problems at a distance, and it takes me gas to find out anything concrete. Forget something, and back I go. Aghhh!

Thanks again.

Last edited by AndyF; 09-21-2013 at 11:14 AM.
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Re: Center of Balance

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Originally Posted by AndyF View Post
.....Haven't I heard somewhere that the CB is indicated on the side of the hull somewhere?
While marks for sling locations are quite common, I don't think I've ever seen a 'CB' location mark - but it would make sense for a trailerable (which I've never owned).. and somewhat irrelevant for a boat that 'lives' afloat.

We do have a prominent designer here on the board, maybe he'll have a better idea...
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Old 09-22-2013
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Re: Center of Balance

Quote:
Originally Posted by Faster View Post
While marks for sling locations are quite common, I don't think I've ever seen a 'CB' location mark - but it would make sense for a trailerable (which I've never owned).. and somewhat irrelevant for a boat that 'lives' afloat.

We do have a prominent designer here on the board, maybe he'll have a better idea...
Any side shot photo of a Halman 20 on trailer should provide a good extrapolation of the CB placement by drawing a line straight up at 90deg from the trailer frame as a base line. For a tandem axle the line would be drawn straight through where the tripod pivot would be between the wheels, and for a single axle, through the center of the wheel. On one picture I picked up off the web, it came exactly between the two rear windows.

Mind you this doesn't mean this is an exact formula, but just an indicator where the driver determined was a reasonable balance point to obtain good balance on the tongue for his particular case. Everyone decides what's good for him. However, that's good enough for us as a starting point to place the running gear. It could be attached temporarily with hanger bolts then shifted for or back observing tounge weight, then welded into place.

Just a thought.
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Old 09-23-2013
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Re: Center of Balance

you'll have seen these then:



more pictures here, including single axles:
https://www.google.ca/search?q=Halma...&bih=862&dpr=1
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Old 09-23-2013
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Re: Center of Balance

If you mount the axels and fenders to an angle iron that will adjust fore and aft on the trailer frame you will be able to set the tongue weight where needed. You can either drill and bolt the angle iron into place or weld them. There are boat trailers built this way.
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