Trailer design or re-design and input needed

[MacGyver]

Hey Everyone!

For a long time I have wanted to modify the current trailer for the 1989 CP19 I own. Some issues is the height as to which she sits overall and combined with its ease of launching, the small tires that the current trailer uses aren't found easily on the road if issues strike, and also the ability for it to self store and not have a ton of things like the motor taking up shop space in the off time.

The current trailer is the galvanized, bolt together kit like setup that seems to have come with the boats when newly purchased. It isn't horrible, could be lived with, but in redesigning the axle setup looking at several options, I feel like I could build a trailer that would better suite the overall needs while also using an axle that would help to not only lower it down, but also make it where the trailer itself helps lower the boat and store all the things as she is sitting. It would be really nice to store it all on the trailer and when I wanted to go sailing I could just hook up and go.

With that being said, I have sourced a Dexter Torflex axle, Number 10 or 10F, which listed the calculated dimensions of 3 tire sizes: a 13, 14 and 15 inch rim size. This has given me the ability to potentially lower the boat by nearly 6 inches total, going off of the keel to the ground measurements.

Here is where I need some help:
Has anyone used a Torflex axle? This type has a internal rubber setup that the axle itself twists on giving it the suspension overall.

Secondly, I cannot identify what size material I should use for the main frame of the trailer. I plan to run a painted steel frame, and have been looking at a trailer at the marina close by, which was made of 3 by 4 tubing. I have seen pictures of a PERFORMANCE made trailer where it is a C channel outer frame setup, but I am unsure of the size of that C channel. I am looking for pictures and measurements or whatnot of or for boats sized around that 2k pound weight design, or heavier, in order to help center the build materials up overall.
If you are able to help on sizing, a height, width and material thickness would help greatly, and a picture can always be sent to my email if needed.

If anyone has any input for me I would appreciate it, as I want to sketch out the overall design and then using a materials book I have is to find the weight of the designs and see what that leaves me for axle capacity and the like. At this moment I have not found a good way to help me identify the material sizes that would do what I want it to do safely.

Thanks to all able to help, I do plan to chart this project out and list it all when I am done. Not sure how soon I will begin but I am most certainly leaning hard on doing it this way instead of working with the current setup.

Mac

[crazycarl]

Many, many years ago I had a home built boat trailer built from 1/4" welded "C" channel. As you with our current trailers, the "C" doesn't hold water like a tube frame and allows you to monitor all the surfaces for corrosion. As for lowering it, don't go so low your striking road debris. I installed a 5200lb axle with a 4" drop and with 15" wheels keeps the boat at it's original height. I have come upon some ramps that aren't sailboat friendly. For those I have an extended hitch I connect. A tongue extender would be easier though.

The company I went with makes the axles to order. You request what drop you want.
There is a thread on it here.

Hope to see you at this years CLR!

[kickingbug2]

    seems to me that rural king in belleville sold drop axles at one time. maybe they still do. i did consider a drop axle for my catalina at one time. i went with 13" wheels and lowered the keel skid. my trailer has a slide out extension. i also made a tongue extension that goes into the receiver.  carl is right dont use tubing open channel is best. the boat fits in the garage. when i built my garage i made the door openings shorter than the doors. i ended upmaking the door opening taller to accomodate the boat. after that no problem. i still think the drop axle might be a good.  idea for the larger tires however i dont forsee any long trips in the future as i have all the sailing i need 25 minutes away. if you need help working on your trailer give me a yell.

[MacGyver]

Thanks to you both!

Carl, I agree with the C channel idea, I think I may have settled on a use of the current framework, making a sliding bolt on rail that extends the width some, and mounts the axle. I was able at work to calculate the total drop amounts and can get a 2.5 inch drop on a 15 inch rim/tire, 3.5 inch drop on a 14 inch rim/tire, and a 4.5 inch drop on a 13 inch rim/tire.

The sliding bolt on rail I have sketched out and wanted to have something adjustable similar to the current setup, that way I could slide it forward or backward if needed to rebalance the whole setup out. This would be ideal to widen the tires out some as well, to help with the width of the trailer, and so that I can add some running boards potentially.

I am leaning towards the 14 inch just because I think the camper runs that same size tire so spares and such would be the same size.

Steve and Carl,

I do plan to do something with the tongue as well, an extension setup or something. I have a 10 ft long extension that was given to me, to be used on the truck side, and I have used it with the trailer jack down as that lever arm is really insane to me....... I hope to finish the design on the tongue extension to make it easy to use as well as a good frame for the mast system potentially
Ill let you know once I am able to buy the parts for the project, gladly take some help when that time comes for assembly, the boy (7) isnt much help LOL

Mac

[crazycarl]

Your drop calculations are off. My axle is a 4" drop with 15" rims/tires. That keeps the trailer at its original height.

If you go with a 2.5" drop and 15" tire, that will raise the trailer 1.5".

A 4.5" drop with 13" tires will have you scraping pavement with every bump.

[MacGyver]

Your drop calculations are off. My axle is a 4" drop with 15" rims/tires. That keeps the trailer at its original height.

If you go with a 2.5" drop and 15" tire, that will raise the trailer 1.5".

A 4.5" drop with 13" tires will have you scraping pavement with every bump.

On a standard build axle I think your numbers are correct. The axle I am looking at is a Torflex by Dexter, No springs as the suspension is inside the axle tube, which would ride directly under the side frame rails of the current build of trailer. A arm extends backward and upward, and then the axle stub comes off that for the hub assembly. Pretty neat setup and I have seen this style around for a while on even really heavy duty trailers

Check out page 24/25 if in a PDF viewer, otherwise on the actual page numbers of the PDF pages, see page 23, 24.
The axle is a 10 / 10F, on the second page for this axle it shows the tire sizes and you can see the dimensions listed also. Let me know what you think.
https://www.dextergroup.com/user_area/content_media/raw/2020.05_LIT-122-00.pdf

If it doesnt link right, here is a copy and paste version
https://www.dextergroup.com/user_area/content_media/raw/2020.05_LIT-122-00.pdf

Mac