View Full Version : Convert boat trailer into utility trailer...

12-22-2015, 09:51 AM
Has anybody ever tried to convert a boat trailer into a utility trailer? My boat stays on a lift so I really only use my trailer a couple of times a year so I am thinking about building a removable deck out of treated lumber that I could jack up and back the boat trailer under when I needed a flat bed. The thinking for me is that I could have a good sized utility trailer (probably a 16 or 18 ft deck) without the extra maintenance and more importantly storage space of a second trailer. Good idea or bad idea, any thoughts?

12-22-2015, 11:48 AM
I was thinking of doing the same thing myself but with a double aluminum PWC trailer. Something I can haul brush and things like that with. I am not building anything that will carry a large amount of weight. I was thinking of a removable stake bed. I would rest the 2x4 "frame" of the bed on the frame of the trailer keeping it off of the bunks and secure it with straps or square U-bolts. I have seen plenty of these conversions but they all seem to be permanent. I can't justify buying a trailer just for that and I have an empty massive storage shed to keep it in.
That being said I am sure it won't pass DoT (state or federal) standards but this is in a rural area where I have seen a lot worse.

12-22-2015, 08:44 PM
Seems easy enough, the key is designing it so it comes off and on easy.. 4x8 sheet of plywood and some blocking, maybe a strap to hold it down..

12-23-2015, 10:43 AM
Yeah that was kind of what I was thinking. Basically just a box with 2x6 or 2x8 headers that would sit on top of the trailer frame and then 2x4 or 2x6 stringers on top of that and decked with treated plywood or 5/4" deck boards. I think I would build in a lip on the headers that sat inside the frame to prevent side to side and front to back movement and then use the transom straps plus either some u bolts or additional straps up front to hold it down. As for removal I am thinking I would mount 4 trailer jacks on the corners so I could just jack up all four corners and back the trailer under it. The front corners would need to telescope out to clear the fenders but that wouldn't be a big deal either and it looks like the guide poles have quick release pins so I could just take them out when the bed is on. I am going to put together a parts list to see how much it would actually cost me and if I decide to go for it I will post up some pictures.

12-23-2015, 11:28 AM
Instead of overhanging the fenders widening the whole thing by a lot maybe just build in a tunnel where you could slide in 2x2 steel square tubes into the frame you are building when it needs to be raised by the trailer jacks. It would save on wood, weight and maybe money.

12-23-2015, 02:44 PM
One concern is going to be the center of gravity of a heavy load that sitting on a somewhat raised platform thats nested on the bunks. This also increases the leverage on or off of the tongue. Centering a heavy load with be more difficult

12-23-2015, 02:59 PM
Thats a good point but I probably wouldn't use it for anything too heavy. I am thinking most of my use would be just for random house projects where I need 16 to 20ft boards, a load of mulch, hauling around a couple of four wheelers or golf cart, etc. If I need to haul something serious like a car or a tractor (which is almost never for me) I have a couple of friends and family that have true car haulers and low boy trailers that I could borrow. For that matter I could borrow them all of the time if I wanted to but it would just be more convenient to hook up to my own trailer when I decide I need something on a whim.

I did a quick ballpark estimate for materials and it came out to about $450. I think for that plus a day/weekend of my time it is probably worth giving it a shot. Weight estimate on those materials is about 1200lbs so that would still give me about 3000lbs of capacity before I got close to the empty weight of the mojo which should be plenty for what I need.

12-23-2015, 08:00 PM
I do have a utility trailer with an old boat trailer as the frame and a pickup box bolted to it. A couple of people could place one onto the trailer and use U bolts to attach it to the bunks. The weight would be evenly distributed on the bunks. I've had mine for over 25 years and now the box and tailgate is worth some money. I don't use it much and I'll borrow the license plate from the boat trailer when I use it. It is nice to haul stuff that you don't want to crap up the back of the truck with.

12-23-2015, 09:45 PM
I did exactly what you are talking about with a galvanized pwc trailer, plywood, and u-bolts. Used it to trailer an ATV when not jet ski season. Worked great, only used it two seasons though before getting rid of ATV, so can't really comment on long term reliability. I didn't need any blocking as I used the bunks as support (2x4 on edge).

12-26-2015, 09:29 AM
What is going to stop the wood from scratching the paint on the trailer?

12-28-2015, 11:43 AM
Yeah good point. Maybe glue some carpet on the wood where it will contact the trailer.

I think this would work well for little $ but the more I think about it the more I think it might not be worth my time/effort. I can carry long boards now on the boat trailer just by sliding them between the bunks so I wouldn't really gain much capability by building a deck for it. I still might tackle this at some point but it is sliding down on the project priority list.

12-28-2015, 02:23 PM
couple of things to consider:

you still have to store whatever deck you build
you may jack up your trailer.

I'd rather rent a trailer when needed than have to explain to a potential buyer (who may need to always use the trailer) that it was scratched up due to me hauling stuff.

12-31-2015, 03:46 AM
Ya'll just need some plywood, u-bolts and duct tape. That'll keep the trailer from getting scuffed up. Good to go. ;)