Just wanted to share the trailer drawings I mentioned a while back. Might be useful to someone who is looking to build one from scratch. The drawings are not complete as there is no tongue, lights, or axle/wheels. But, the most difficult part of building a trailer is making decisions on overall size, etc.
We have also made some separate detail drawings of the flip-down trailer stand we are showing attached in the drawings.
The measurements for this drawings came directly from my drift boat trailer, which is a manufactured trailer, but I do not know the maker. Please shoot any questions you might have as it would be fun to work through them with my students.
More to follow as we detail out the drawings.
First is a rendering, should show on your screen. Then, two drawings (one with dimensions in .pdf form)
Thanks for doing this,I'll need it in the future.
Are the extensions on the rear frame tube the area where the Lights are to be mounted? The only thing that might be an issue is a shin banger (ouch!) as your loading the boat and walking around it. You ever walk around a Pick up with a Hitch plugged in the back and bang your shin on it? Just something to think about.
I have made a similar drawing for a trailer for the DB I am building. The Width of the frame seems to be critical to the width of the boat at the Chine and with the flair to the Shear you need clearance to the fenders. I think 2-3 inches would be a minimum clearance. What's you thought on this?
Thanks for the feedback Dorf. I took these measurements from my current trailer, on which sits a typical 16' (14'8") x 48" double-ender. I now think the trailer I have is actually a Baker and was made in 2002.
Yes, the little extensions on the rear rail provide just enough additional width to insert lights into the rear rail. Quite tidy really. I sure have banged that shin more times than I'd care on receiver hitches, but that has never been an issue with this trailer. It's really not much stickout, and with the width of the wheels/fenders, and the fact that the stern of the boat sits well behind the back of the trailer, the path you typically walk around seems to avoid it quite nicely.
However, your question made me think that another great option for lights would be to build them into the back of a step located behind the wheel well and just eliminate the extension on the rear rail. I've seen this on other trailers, and maybe we'll work one up that way. Thanks for the idea.
I currently have my boat sitting on the trailer upside down as I'm slowly re-finishing the bottom (see my Blog entry). But, I do believe that the width of the trailer would accommodate a 54" bottom boat quite nicely. You are right 2-3" would probably suffice (in extra width on each side beyond the chines. However, your choice in axles/springs (leaf or torsion) may affect the exact width of your frame as well.
Please keep the thoughts coming as I'm using this as a real-life design exercise for my students, and I like to have them consider as many elements as possible for all of their projects. Eventually, I'd like to have a file of many different options and sizes available.
Would love to see what dimensions you settle on eventually.
Tom, here's a couple to consider. What are the advantages or disadvantages of leaf spring suspension versus a torsion axle assembly? How do you select the appropriate spring rate or torsion spring assembly for a load that is perhaps not much more in weight than the weight of the trailer?
What happens to the load, in this case a drift boat if the spring is designed for a much heavier load? Will a drift boat suffer damage or excess vibration if the springs aren't sufficently soft to flex based on the load being carried, in other words will the boat be bounced around if the springs don't flex much?
Is it as important to match weights with a torsion setup? How does this system work? Do you change something to match loads or are they one size fits all?
If you don't know the springs capacity of a trailer you have how could you determine the possible load capacity of it?
How do paint, powder coating and paint or powder coating with galvanizing determine the life of the trailer? Which is the most cost effective? I once bought a trailer in Salem, Oregon that had spent a great deal of time on the Oregon Coast. Big mistake, the outside of the metal on the trailer was a little bit rusty. The unprotected interior of the metal frame was almost rusted through.
Where is the best place to mount a license plate so it won't be damaged? The back of most trailers has a roller? Where do you put it to comply with state requirements?
What's the best way to make mounts for tie down straps? Where is the best location?
How do you get a homemade trailer registered with state licensing agencies?
How do you "balance" the load to achieve an appropriate tongue weight? What is an appropriate tongue weight?
How do you test and troubleshoot non-working trailer lights and light connections on your tow vehicle?
The last one I promise, how can you jack up a drift boat trailer if you don't have a jack and you are out at the river?
Hope this helps? Inquirring minds want to know?
If I may add my $.02's worth on the questions you pose above.
Most, if not all commercial built trailers have a load rating. Therefore, it should be easy to match it to the weight of a loaded boat. I don't have a clue what a 16 ft. double ender will weight, but somewhere around 600-700 lbs seems reasonable to me.
Torsion or leaf springs have their advantages and costs, so it comes down to load ratings & personal peference as I see it.
License plates usually are mounted on the rear and to left of center. Iv'e seen them loacted on the left rear fender. I don't think it needs to be lighted, as some tail/turn lights have a mtg. bracket for one.
As to the location of hold down connections on the frame. I'd think they be as close as possible to the point at which the boat is supported on the bunks/roller. To keep the pull forces vertical. The Stem support should keep the boat from sliding forward/aft.
In Michigan to get a trailer registered we just need to get a certified weight and and pay the State a one time $ 75. Easy peasy!
To balance the trailer and maintain the trailer's tongue weight is a little trickey if your not a registered engineer. I have made a 1/6 drawing of the DB and with it's plan's baseline horizontal, I laid in the trailer beneath it so as to support it in two places in the same horizontal plane. Note: tongue weight should be ~10-15 % of the trailers loaded weight. To tweak the final toungue weight you can leave the tongue a little long and trim it as you need to. I will be starting with 8 ft. and using a bolt on coupler it's just a matter iof cutting it shorter as need. It's a whole lot easier than adding length or moving the axle.
Most vehicles have a screw jack of some kind and they usually work well in the trailers frame or axle to change tires. At least the one in my P/U truck does. Been there and done that. Can get one cheap at a "Junk Yard", cheap.
As far as making non-working lights work again. Good Luck! However, an Automotive Elec. Engineer told me a long long time ago that on 12 volt automotive systems (chassis negative ground) 90% of the problems are caused by a bad ground. I've found this to be true many times on several trailers I have owned over the years.
Hope I haven't bored you all,
When I built my boat trailer and with the boat sitting where it should I then welded a couple of weld on eye bolts directly below the oar locks so that when I strapped the boat down for travel the strap went thru the oar locks and not over the hand rails where it will wear off any finish. Plus it is about dead center in the trailer and boat so you only need one strap.
For those who want to know how a rubber torsion axil works
Place one square steel tube inside a larger one and fill the corner spaces with long triangular strips of rubber. Instead of a steel spring we twist the inside tube and compress the rubber.
In my opinion, they bounce a bit less the steel spring axils and we can keep the bed lower.
I have found a local source here in Mid-Michigan who builds trailers and after spending some time there a week ago I discovered they build custom axles. If I need it to be 48, 50, 52 or any other dimension they'll make it. I am going with them for this very reason. They also have an feature where they drill a hole from the end of the spindle inboard 3-4 inches and then add a couple of smaller cross holes. With a grease fitting in the end of the spindle the grease will come out in between the bearings. It's a much better situation than bearing buddies. Cost is $ 231.11 for a 2200 Lb. axle, 1000 lb springs and all the hangers etc to mount it to the frame. It's a good deal at that price. You get the option of designing your trailer to fit your boat.
Just another option,
Would you mind sharing the contact info for the Mid-Michigan trailer builder? Almost completed the build of my 18' 10" LOA Grand Banks dory (i.e., old school drift boat) here in Indiana and, of course, a trailer is one of the next steps. Just flipped it over yesterday to finish the interior. Yeah!
PS. Tom Anderson - Thanks for the drawing plans. Being a complete rookie at this, I need all the education I can get.
Sorry I missed this request until today. The guys who build custom axles are just outside Bay City, MI. They are:
112 S. Huron Rd.
P.O. Box 504
Kawkawlin, MI 48631
Contact: Scott Ferguson, Sales
Tel: 989 686-6176
Toll-free: 888 686-6180
I hope this helps,
Thanks for the contact info.
Thanks for taking the time to do this Tom!
Are we going to get to follow the build through photos? (I am assuming they will actually build one?)
This is good timing for me as I am looking for ways to modify my existing homemade trailer that came with an old junk homemade 20' fg driftboat I bought to fit both that boat, and then when I get it rebuilt, a 16' Don Hill Mckenzie that I picked up. Also considering building my own for the DH when the time comes. I have the skills & most of the tools but lack shop space.
Anyway, always fun to watch someone work through the same process I will need to!