New Trailer Needed -- Help

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RHC
Engineer
Posts: 107
Joined: Sun Mar 20, 2005 6:57 pm
Location: Half Moon Bay, CA

Re: New Trailer Needed -- Help

Post by RHC » Sun Aug 09, 2015 7:38 pm

Can anyone recommend an alternative to loadrite for folks in the west coast (San Fran)?
My original mac 26X trailer (1997) broke while pulling boat up ramp w/ water ballast full.
To my surprise, failure was in the hefty tube leading to the hitch, where the two side beams converge.
It was also where the spare tire carrier is mounted with ss brackets (my friend said it was the dissimilar metals effect that did it in).
Anyways, I'm now in the market for dual axle galvanized replacement.

btw: made me think that of course the highest load the trailer sees is when the water ballast is full. Makes sense to drain the ballast prior to trailer recovery.

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Tomfoolery
Admiral
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Joined: Tue Jul 05, 2011 9:42 am
Sailboat: MacGregor 26X
Location: Rochester, NY '99X BF50 'Tomfoolery'

Re: New Trailer Needed -- Help

Post by Tomfoolery » Sun Aug 09, 2015 8:48 pm

RHC wrote:To my surprise, failure was in the hefty tube leading to the hitch, where the two side beams converge.
Actually, that it broke there is no surprise, as that's the highest stressed part of that pole tongue. Others have had the same thing happen, in the same place. And rust, especially the bottom of the tube, which is under tension from the bending moment, makes it weaker. And that tongue is not exactly overbuilt, either.

But it's easy to replace, if you want to repair the trailer instead of replace. Use 1/4" wall tube instead of the original 3/16", and/or a slightly deeper section, like 4x3" instead of the original 3x3".
RHC wrote:btw: made me think that of course the highest load the trailer sees is when the water ballast is full. Makes sense to drain the ballast prior to trailer recovery.
Open the vent and the gate valve at the stern before you load it onto the trailer. As soon as the bow is raised, even a little, ballast will flow out. The further the bow is raised, the more water will flow out, and you should end up with a hefty portion of water out of the tank before you haul it more than a few feet up the ramp. That way you're not putting any great load on the trailer.

C Buchs
First Officer
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Joined: Thu Apr 23, 2015 8:49 pm
Sailboat: MacGregor 26X
Location: Camas, WA; 2001 26X w/ 2000 Honda 50

Re: New Trailer Needed -- Help

Post by C Buchs » Mon Aug 10, 2015 10:47 am

Tomfoolery wrote:
C Buchs wrote:Don't forget that you need to find the center of mass of the boat. I'd bet it's not evenly distributed across the boats length.
rszobel wrote:that could be a bit tricky to say the least. how would you suggest finding CG of boat when loaded ?
The original trailer had a tongue weight of about 160 lb, and an empty (tare) weight of 710 lb. For an :macx: loaded up to the GVW of the trailer, which is 3500 lb, the boat and engine and contents would weigh about 2790 lb. So the tongue weight would be that of the empty trailer, plus whatever proportion the boat puts on it, with the rest going onto the wheels.

The distance from the hitch ball to the center of the axle is 225 inches. So the location of the CG of the boat that adds another 190 lb to the tongue (for 10% of the gross trailer weight) would be 190 lb x 225 in / 2790 = 15.3 inches forward of the center of the axle.

The pointy end of the raccoon stripe on the side, where it ends at the rub rail, is pretty much right over the axle, so 15 inches or so forward is just a hair forward of the mid point of the sliding hatch. But it's easy enough to measure from that raccoon stripe end.

That's all based on a 3500 lb boat with 10% tongue weight. The standard OEM trailer doesn't change, but the boat contents and equipment do, so to get an accurate location for your circumstances, you need the actual gross weight, and the actual tongue weight. From there it's some easy cipherin' to determine where your actual C of G is.

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You've got all the math figured out for us and you can calculate the actual tongue weight using the method above. For the weight on the wheels, just pull into one of the roadside scales the state patrol runs for the truckers. They'll let you weigh (at least in Washington State) with just the trailer's wheels on the scale.

Jeff

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