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gcarter
10-18-2014, 09:51 PM
The TR trailer is a typical aluminum trailer w/Torsion axles, disc brakes, and bunks that overhang the rear crossmember by 32". This really bugs me and while I have a plan to fix it, I don't know a lot about trailers and I'd like some input, or opinions......

In the first picture, the port bunk is sitting where it has been w/all the overhang:

http://www.donzi.net/forums/attachment.php?attachmentid=81104&d=1413683384

The second picture shows the bunk turned around w/little overhang:

http://www.donzi.net/forums/attachment.php?attachmentid=81105&d=1413683408


In the third picture, the two marks on the frame I-beam flange shows where I think the CG is now (the mark on the right), and where it would be w/the bunk overhang eliminated (the mark on the left) (aft is to the right).

http://www.donzi.net/forums/attachment.php?attachmentid=81106&d=1413683426


Now, it seems to me that neither CG location is where it should be (of course my CG estimate is just a guess, so it could be off by 6"-8"). What I'm thinking of doing is moving the axles forward by relocating the rear bolt hole location to the forward hole in the frame and drilling a new forward bolt hole through the frame lower flange. W/the eliminated bunk overhang and the relocated axles, the CG should be better.

http://www.donzi.net/forums/attachment.php?attachmentid=81107&d=1413683438

Now to the pointy end of the trailer.....the bow post would have to move forward the same amount as the eliminated overhang, so my current setup would have to change:

http://www.donzi.net/forums/attachment.php?attachmentid=81108&d=1413683459


So I'm thinking by extending the 3" square tube that makes the tongue would be replaced by one about 30" longer so the post would be relocated forward of the of the frame, like this Magic Tilt trailer:

http://www.donzi.net/forums/attachment.php?attachmentid=81109&d=1413683477

I'm looking for input as to whether this is a good idea, or not. Or am I wasting my time?

Greg Guimond
10-18-2014, 10:09 PM
Why not find your true Center of Gravity?

BUIZILLA
10-18-2014, 10:09 PM
measure 48" from the rear of the frame rail and make a mark, IMO the center of the rear axle spindle should be at that mark..

typically, the center to center of the spindles with 15" tires should be 34", 33" centers with 14" tires, then center the fender location to the tires,

you'll find the ass of the boat will end up being about 4" past the rear of the frame and you can cut the bunk flush there or leave it 2-4" longer

with the hull positioned there measure fwd. to the bow eye location, and that'll be your front V block location, from there you can figure your new tongue length

once you measure all that, let me know where the crankshaft balancer location is, relative to the axle mounts

once again, that's IMO.

MDonziM
10-18-2014, 10:15 PM
George,
I can take a picture of it tomorrow if you like but I moved my winch post forward and bolted it right thru the top and bottom of both I beams with 1/2" threaded rod and a 3/8" steal plate underneath. Looks like you could go forward 1'-1 1/2' this way. Then if you move your axels back 1' you should be able to cut 2' -2 1/2' of bunk off.
- M

yeller
10-19-2014, 02:42 AM
I'd do it George. I don't like the looks of extended bunks either.
You can easily extend the tongue. Mine is well over 4' long, but it is 3"x4". Not 3x3.

What did you end up using to clean your frame? Looks like it cleaned up nicely.

yeller
10-19-2014, 02:50 AM
This says CG is 64" forward of the transom. There are going to be varying factors though.

gcarter
10-19-2014, 07:25 AM
This says CG is 64" forward of the transom. There are going to be varying factors though.

Thanks for that diagram Glen. I'd forgotten about it as I think I have it somewhere.
I'd guessed it to be 6' (72") so I wouldn't have been far off.

gcarter
10-19-2014, 07:31 AM
What did you end up using to clean your frame? Looks like it cleaned up nicely.

I used 3M Scotch Brite pads (large, thick, and very coarse), soapy water, and some 320 wet or dry paper.
It now has a nice "brushed look". Should be easier to maintain than polishing.

MDonziM
10-19-2014, 10:32 AM
Here George, if you're interested. Like Buiz said, the end of my bunk is 4'2" from my rear axel. The winch clears my Tahoe tailgate by about 4"

gcarter
10-19-2014, 12:22 PM
OK, I just finished re-measuring the trailer w/Jim's dimensions in mind, and the Donzi PDF.
By moving the axles fwd by one bolt hole location, the rear spindle is 42" from the end of the frame. Considering the amount of work to relocate off the existing holes and to redrill all the holes, instead of half of them, I think I can live w/42".
The rear overhang is approx. 6" past the frame. Measuring fwd to the bow eye (approx 21.5'), the fwd end of the bow post base is ahead of the aluminum frame, while the rear is on top of the frame. I'll definately need to add 12" to 18" to the tongue.
Also, the trailer may be about 18"-20" shorter than it is now.
Thanks for all the input guys. Especially Jim for the dimensions, Marshall for the base mounting scheme, and Glen for the Donzi PDF.

yeller
10-20-2014, 09:12 PM
I used 3M Scotch Brite pads (large, thick, and very coarse), soapy water, and some 320 wet or dry paper.
It now has a nice "brushed look". Should be easier to maintain than polishing.Thanks George. I'll give that a try. It looks good....and I agree, it should be easier to maintain than polishing.