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 Post subject: Trailer re-build and re-design
PostPosted: Fri Jul 28, 2017 11:20 am 
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Joined: Sun Aug 18, 2013 11:33 am
Posts: 149
Location: Townsville, Qld
Hi all, Teria's old trailer frame is finally kaput, so beginning to build a new one.

The story so far...Some of the 3x2" box section beams were rusted through underneath. So i took the boat on it's early-model trailer to my shed. When unloading the hull, forgot to use the tilt function of the trailer so the already rust-weakened frame buckled under the hulls load (and became the tilt function!) :oops:

So now, aside from buying a brand new trailer at great cost, the other choice is to scrap the old frame entirely and rebuild/weld-up a new frame from scratch, re-using all the old fittings and running gear. Hopefully it's far stronger than before. It's also a good chance to add extra cross beams and rollers etc in a new design and prevent a "stuck on trailer" problem I've had.

My thoughts after seeing other trailers so far are to use open C section beams, so rusting can't ever hide internally. Increasing main beam vertical width to 4" or more (still 2" width to fit wheel assembly) . Buy pre-galvanized steel and zinc prime the joints. (Hot dip galvanizing would be the ultimate but moving the heavy frame could be a big problem). The main design change is to increase the draw bars length by a few feet (to get the trailer deeper underwater for launching/retrieval)

Work so far - sledge hammered the old frame straighter again, stripped all the fittings off, took allot of measurements and made drawings of it, left the old frame intact for use as a template/workbase and took some photos along the way.




So before buying the wrong-sized steel (and stuffing it up) some detailed info of other investigators trailers steel beams would be greatly appreciated.

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Andrew
Investigator #9 Teria
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 Post subject: Re: Trailer re-build and re-design
PostPosted: Fri Jul 28, 2017 9:28 pm 
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Joined: Sat Feb 07, 2015 8:57 pm
Posts: 65
I've recently cut the whole back section off my trailer as it had started to show signs of cancer. Made a whole new section and got it galvanised. See photos here:

https://m.facebook.com/lawanddisorder563/photos/a.471715363170010.1073741865.131489233859293/482185845456295/?type=3&source=54

I thought the same as you and added an extra 500mm of length to help with launching/retrieving but honestly it's made no difference at all. I think it's in the angles, 500mm longer trailer equals 50mm of extra depth depending on the angle of the ramp.

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Greg
Investigator #10 - Law & Disorder
Sydney

https://www.facebook.com/lawanddisorder563/


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 Post subject: Re: Trailer re-build and re-design
PostPosted: Sun Jul 30, 2017 8:28 am 
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Joined: Sun Aug 18, 2013 11:33 am
Posts: 149
Location: Townsville, Qld
Nice work on the trailer, (and facebook page)

What dimensions are your side beams Greg? they look pretty solid
The V drop in my cross beams is already quite low, so can't increase that.

Cheers

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Andrew
Investigator #9 Teria
Townsville


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 Post subject: Re: Trailer re-build and re-design
PostPosted: Sun Jul 30, 2017 9:56 am 
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Joined: Sat May 05, 2012 4:25 pm
Posts: 178
Location: Gold Coast
I'm also doing a bit of maintenance on my trailer at the moment. Mine is a bit like Grandpa's axe, and I've replaced just about all of it over the years. My philosophy has been to replace like with like, so what you see in the photos below is pretty much how they were originally built.

My recommendation would be to build the main frame from 75mm x 50mm RHS and have it hot dipped galvanised. It is only about 3.6m long and .95m wide with two cross members so is light enough ans small enough to lift onto the roof racks of a car. (That's how I carried mine.) You are lucky to have a galvanising works nearby at the Bohle, so transport shouldn't be a problem. If you go this way, I would also recommend you include the 1/2'' round stiffeners on the rails as these were part of the original design. The rest of the trailer parts bolt to this frame with U bolts and can be made from standard 50mm square gal RHS as these can be easily replaced when they rust. If you can, try and source (or have made) some S/S U bolts to bolt the roller support members to the frame. These will make removal easy and they will last forever. It also pays to apply MolyKote 1000 (or similar product) to all threads. It's a bit of a messy job, but pays off in the long run.
I had my frame fabricated and galvanised in 2005 and so far it is not yet showing any signs of rust.

One problem I encountered a few years back was with the winch post. It completely snapped off at the base when I was winching the boat back on the trailer. The post had rusted from the inside so it would pay to check that out if you want to reuse this part. There was no visible rust on the outside before it snapped off.

Your trailer looks like it is fitted with 13" wheels. The original trailer had 9" rims (4.5 x 9 rims with 6.00-9 tyres) so fitting smaller wheels will substantially lower the boat and making launching easier. You could also consider using drop axles, although I have not used them myself.

I've included a couple of photos of my trailer so that you can see what I mean about the frame. If you want to copy the design, I'm happy to take some measurements and more photos. Good luck with the project.


Attachments:
Trailer rear view.jpg
Trailer rear view.jpg [ 33.75 KiB | Viewed 2228 times ]
Tilt Mechanism.jpg
Tilt Mechanism.jpg [ 21.85 KiB | Viewed 2228 times ]

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Ray
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 Post subject: Re: Trailer re-build and re-design
PostPosted: Tue Aug 01, 2017 4:06 pm 
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Joined: Sun Aug 18, 2013 11:33 am
Posts: 149
Location: Townsville, Qld
Thanks for the good info, its much appreciated

"Like for like" sounds like a good philosophy. The existing fittings will all go back on easily then. The 12mm strengthener bar is a must have with 75mm x 50mm box section.

It would be great to see a design diagram of your trailers specs.

My frame is 1.3m wide and 3.6m long. (the draw bar is only 1.1m long from pivot to coupling, way too short, it is rusted out too)

Hot dip galvanizing sounds like the best way to coat it. Probably can chain-block the frame up in the shed and lower it onto my ute's carry racks for transport to the gal plant. I met a bloke who worked at the Bohle plant, said there's also another one at Stuart.

I've tried to reduce my photos (windows 11) below the 90kb allowed on this site, but they are low resolution.


Attachments:
DSCN0258 Teria trailer wheel assembly (190x183).jpg
DSCN0258 Teria trailer wheel assembly (190x183).jpg [ 88.06 KiB | Viewed 2201 times ]
DSCN0257Teria trailer frame rust out (230x137).jpg
DSCN0257Teria trailer frame rust out (230x137).jpg [ 89.24 KiB | Viewed 2201 times ]

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Andrew
Investigator #9 Teria
Townsville
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 Post subject: Re: Trailer re-build and re-design
PostPosted: Fri Aug 04, 2017 10:27 am 
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Joined: Sat May 05, 2012 4:25 pm
Posts: 178
Location: Gold Coast
Your trailer is a different design to mine. You already have a drop axle to compensate for the larger wheel diameter. The angles in cross members will also allow your boat to sit lower than if it had straight ones. I think your design is better.

The dimensions of my trailer are:
drawbar = 1800mm
Frame length = 3600mm
Overall length (not including coupling) = 4950mm

I'm presently considering fitting brakes to my trailer. The boat ramp I use is only about 300m from my house so I haven't worried about them before but now I might want to go further afield so will need to fit them to stay legal. I'm presently tossing up the benefits of disk vs drum and hydraulic vs cable. I also like the range of AlKo rubber suspension axles. What brake system, if any, do you intend to fit?

The photo shows my draw bar arrangement. I put the brace on the winch post as extra "ïnsurance" but it really isn't necessary. My winch is a three stage design and it works well. The extra low gearing really helps to winch the boat that last metre or so.


Attachments:
Draw Bar Dimensions.jpg
Draw Bar Dimensions.jpg [ 83.82 KiB | Viewed 2190 times ]

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Ray
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 Post subject: Re: Trailer re-build and re-design
PostPosted: Sat Aug 05, 2017 7:52 pm 
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Joined: Sun Aug 18, 2013 11:33 am
Posts: 149
Location: Townsville, Qld
Thanks for the draw bar info, I think i will build new one a similar length 1.8m

Yes the drop axle on bigger wheels seems like a good idea, better for the highway and keeps the keel low.

Plan to refit the whole wheel and axle assembly as it is. The brakes are disc ones - they seem to be working fine. They are activated via a cable to the trailer coupling. There is a spring and plunger inside it which moves when the boats weight shifts forward on deceleration, this moves a pivoted arm (pic attached)..the arm is attached to the cable via a pulley and adjuster screw (not pictured)

Due to my low res images here , i'm updating my Teria blog with far better images of the the whole process .. :)

http://teria563.blogspot.com.au/search/label/trailer
https://www.youtube.com/watch?v=FTxSZUh ... e=youtu.be

The photo (plus dimensions) of your draw bar and winch set up is very help-full, there are many details - food for thought. i like the adjustable bow crutch running through the winch post.


Attachments:
File comment: Teria disc brake
DSCN0260 (150x113).jpg
DSCN0260 (150x113).jpg [ 89.29 KiB | Viewed 2176 times ]
File comment: Teria tow hitch and brake actuator
DSCN0377 (150x113).jpg
DSCN0377 (150x113).jpg [ 89.05 KiB | Viewed 2176 times ]

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Andrew
Investigator #9 Teria
Townsville
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 Post subject: Re: Trailer re-build and re-design
PostPosted: Mon Nov 06, 2017 4:30 pm 
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Joined: Sun Aug 18, 2013 11:33 am
Posts: 149
Location: Townsville, Qld
Took awhile to get around it, but finally bought the trailer steel. It cost about $300.

Have 8m of 3x2" (3mm wall) RHS for side beams.
8m of 3x1.5" (6mm wall) channel for the cross beams.
6m of 20mm rod and 6m of 2x1.4" flat bar for the top rail.

My rebuild will be similar to the original, but using channel across beams so no rust traps. May leave the RHS ends open so saltwater can be hosed out easily. Intend to get it hot dip galvanized.

I got diverted from the trailer for some months by building a roof over my old 40 foot sea container at the boatyard. But it also gave plenty of time to think about the trailer rebuild specs etc. Stuck with the original dimensions, so shouldn't be too many surprises when refitting the gear to the frame.

Put Investigator/sailing photos on the computers screen savers to keep motivated!

Cheers
Andrew

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Andrew
Investigator #9 Teria
Townsville


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 Post subject: Re: Trailer re-build and re-design
PostPosted: Sat Nov 18, 2017 11:11 am 
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Joined: Sun Aug 18, 2013 11:33 am
Posts: 149
Location: Townsville, Qld
Found that the cross beam channel i bought looked way too heavy (see above post 6mm and 10mm walls), so will try out 4mm thick galvanized channel for cross beams (75x40mm) this looks about right and would be a similar weight to the 75x50mm (3mm wall) RHS side beams. Also welding 4mm to 3mm thicknesses should be easier to get right.

Started on the frame rebuild last weekend..http://teria563.blogspot.com.au/2017/11 ... age-1.html

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Andrew
Investigator #9 Teria
Townsville


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 Post subject: Re: Trailer re-build and re-design
PostPosted: Sun Dec 24, 2017 2:58 pm 
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Joined: Sun Aug 18, 2013 11:33 am
Posts: 149
Location: Townsville, Qld
Merry Christmas everyone,

Update on Teria trailer rebuild, Have fitted most of the cross beams and started on the draw bar. Plan to copy the original tilt hinge design, however may move the frame 1 that the hinge attaches to, further back. Intend to extend the draw bar about 6 feet infront of the A frame apex. Blog update http://teria563.blogspot.com.au/2017/12/

Found a good trailer website, this is the page i first found http://www.trailersauce.co.nz/information/draw-bar-design/trailer-drawbar-design-function/ but the site also has allot of other good information about trailer engineering. (It's kiwi but don't worry , aust is covered too )


Attachments:
File comment: Teria trailer frame construction, xmas 2017
WP_20171224_08_43_19_Pro Teria trailer frame xmas 2017 - Copy (160x90).jpg
WP_20171224_08_43_19_Pro Teria trailer frame xmas 2017 - Copy (160x90).jpg [ 89.22 KiB | Viewed 1977 times ]

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Andrew
Investigator #9 Teria
Townsville
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