"M" aluminum trailer concern/suggestion

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Hardcrab
Captain
Posts: 868
Joined: Tue Sep 19, 2006 10:25 pm
Sailboat: MacGregor 26M
Location: "Cease-fire", White 05 M, 90hp, Boggy Bayou, Niceville, FL

"M" aluminum trailer concern/suggestion

Post by Hardcrab » Thu Jan 18, 2018 2:02 pm

A possible concern for aluminum trailer M owners out there.
I was looking over my 2011 aluminum trailer for possible trouble spots to prep for a cross-country tow.
I noticed that one of the four 4" x 4" (3-1/2" x 3-1/2") woodblocks that raise the bunks above the side rails has a deep, nasty split running the entire length of the block from top to bottom.
With a flashlight, I can see the SS through-bolt in the crack.
From what I can see, the blocks appear to be held in place by just that single bolt from the bunk, through the block, then through the rail with a washer and nut.
It seems to me that if the other side of the block were to split, then with a good pothole bounce, both halves could just fall out.
That might be a bad day.
The other three did not have splits as bad, but being wood--it's not if, just when---- perhaps.

How are yours holding up???

I decided to forego wood and cobble up replacements out of 1/4" aluminum plate, 1" aluminum angle, hacksaw, and Aleve.
They somewhat resemble the Roman Numeral Two, with the top flat angled down 68 degrees to copy the factory block.
I made them 1/4" taller than stock to take some of the boat load off of the axle center bunk and transfer it out to the rails.
A 1/4" aluminum spacer plate under the steel bow bunk will keep everything relative.
I might need longer bolts all around, not sure yet.

IMHO, the factory design has to much boat weight on the center bunk of the axle causing the axle to bow downward, causing the tires to cant inward at the tops and wearing the inside tread badly that a lot of folks report.
So, along with the taller blocks, I am also adding a 1/4" aluminum spacer plate between each of the axle to rail mounting locations to "drop" the axle down from the boat to end up with a 1/2" total difference between the axle bunk and the boat hull. YMMV

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RussMT
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Joined: Thu Oct 11, 2007 2:01 pm
Sailboat: MacGregor 26M
Location: Bozeman, Montana "Luna Azul" 2008 M 70hp Suzi

Re: "M" aluminum trailer concern/suggestion

Post by RussMT » Fri Jan 19, 2018 11:55 am

I would love to see what you made. Pics??

I haven't looked at those wood parts in a while. Next time I go visit the boat/trailer I'll inspect. A big crack there could be really bad.

I also agree there is too much weight on the center of the axle. Honestly, I don't know why they put any weight directly on the axle. Before I added a second, mine was definitely bowed as you describe and wore the inside of my tires.

Here is the midst of adding my second axle. The blocks (red arrows) appeared to be okay.
I'd love to know how raising those bunks a bit helps with the axle weight.

Image


--Russ

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