20’ dove tail 12k trailer build

My current trailer has never been a long term solution. It's been a stop-gap between selling my 28' monster enclosed trailer and downsizing to "dude you go to the track maybe 3 times a year you don't need a huge enclosed trailer." Therefore? I'm building my own, kinda. The plan is to have the Cadillac of utility trailers with long ramps and a long dove tail for low cars, a 12k winch on a receiver so i can pull dead stuff up, all the LED's, stake pockets, tie down rails and D rings everywhere, and I even plan to drill any tubes once done so I can hose fluid film inside of everything after paint and then rubber plug them. 
 

using this 12k boat trailer as a base, I will lose 3" between fenders vs the current car trailer but that would only have ever been an issue when I bought the Hummer with wider than stock wheels. Solution is I'll build drive over fenders in case I need to tow a big truck anywhere. I'm looking to the future when I'll end up with my parents' tractor and be cleaning out my FIL's farm full of stuff, and attempting to future-proof myself for many years to come.

Looking like I'll end up with 20-21' overall including the tail. My base got dropped off yesterday. 
 

*I know the perils of welding galvanized and will be flap wheeling it all away from the weld areas and have the proper PPE & will be working outdoors

I've always wondered about boat trailer conversions. Looking forward to seeing what you do with it.

95% de-boated 

The 'P' car is in the shots to make the likes of me make stupid posts to sidetrack the focus of the post ?

On a more serious note, I see some 'plate(welded,top &bottom)' type action where the trailer rails meet the tongue/hitch tube....your house your rules.....carry on maestro.

In reply to 759NRNG :

My buddy Brad's car is spending a week here for logistics purposes

How much of the boat frame are you going to use? Seems like a very long tongue on the front, I assume you'll be building it up in that area?

It got a tongueectomy today. Took off 7' then made a plate for the bottom and sides out of 1/4". Welded all that inside and out then capped the triangles and nose and welded a new coupler on. My leather welding sleeves came today and my lincoln electric respirator came yesterday. Both are amazing and my lungs wish I'd had this respirator years ago

Your arc welds look better than my MIG welds.

Jerk. 

In reply to Curtis73 (Forum Supporter) :

Sorry, dad taught me when I was 12. I still think they're ugly but also nobody is more critical of my work than me

Nice progress. I like this kind of repurpose. Much better than trying to use an old camper.

iansane said:

Nice progress. I like this kind of repurpose. Much better than trying to use an old camper.

seems like you can get a E36 M3ty boat with a decent trailer for less than you'd pay for a marginal car trailer.

some progress was made yesterday 

I did the same thing with a boat trailer and made a little ramp trailer. It tows fantastic. 

What are you doing for the brakes? Can you retrofit electric brakes to that axle? Not saying you can't, asking for a friend....

Lot of dust on that A-body. I drove mine today.

In reply to Patrick :

Looks like good work.  It may be parallax but that break over angle seems severe.  

Run the math for you lowest expected vehicle to be hauled (I'd guess the Skyline) and make sure you have about 1" of clearance to account for flat tires.   

The math is:

Angle=2*atan(GC/(WB/2))

atan is tangent inverse and make sure your calculator is in degrees or multiply the result by 180/pi if your in radians (Excel and Google sheets use radians)

For a 103" wheelbase with 4" of ground clearance I get that your break over angle needs to be <9⁰. 

I can measure mine but I think I went with 5⁰ on my dovetail and I load cars with 96" wheelbase and 2.5" of ground clearance with just a TINY bit of rubbing.  

It's just nows the time to make it exactly what you want it to be.  Obviously the lower angles require longer ramps.   But longer ramps reduce approach angle.  Its a balance just want to make sure you're going to get what you expect.  

In reply to nocones :

I matched the angle (appx 10.5*) of my current trailer. That one has an 18" tail and 4' ramps. I'm at 46" tail and will go 6' for the ramps so the entire car with a wheelbase of 10' or less will be on the angle by the time the fronts hit the flat. 

When I bought the Skyline - definitely my lowest car - the air dam to ramps was the only issue. Ground clearance in the middle third is more like 5-6" with the downpipe being the low point between the wheels at around 4" but only to a foot behind the front wheels. Most of the time the trailer gets used for much taller things with way more ground clearance, so I figured even if I needed to use the jack to lift the nose of the trailer and back of the truck, I'll be OK. I had to do that when loading the Datsun because it has about 2" of clearance. Thankfully that car is gone because it was a bear to load even in my enclosed trailer with a 4' flap on the ramp door

In reply to NY Nick :

Yeah the axles take standard 5 bolt backing plates so 4 of those and 2 new drums get me 4 wheel electric brakes

made and installed the rear crossmember for the tongue 

I'm surprised you didn't move the axles forward a little to take some tongue weight off. 
 

but it's coming along nice

My maths have them in the same place percentage wise as my last 2 factory built car trailers. 

Patrick said:

There's a lot of sexy hiding back there.

P major fist bump on the tongue execution ...you got this big time....will there be a winch at some point in time?

Definitely a plan for getting inop cars pulled on, Brian.

lots of progress today after a recuperation day spent with Carli yesterday.

The red beams are higher than the silver rails where they hit the dovetail break over.  Will you just clamp the top sheet down to take its own form??