View Full Version : Trailer modification help

02-03-2011, 01:40 PM
Hi Everyone,

I picked up a 99 Prostar 205 last spring, it didn't have a trailer and finding a Mastercraft one wasn't happening so I picked up a used Titan trailer that was meant for a Malibu boat. It was either that at $2000 or a brand new trailer at $5000.

My Mastercraft doesn't really sit right on the trailer, the bunks are off a little width wise and also they are not at the right fore/aft angle. The front part of the trailer where the winch sits is also not right and doesn't mesh with the boat.

I was able to use it all last summer, however, I would like to fix it over winter. I put the boat in and out of the water each weekend (in on Fri night, out on Sun night) and only go 3miles from boat launch to cottage, but a couple times a year I'll travel with it over an hour away so I would like it to be SAFE.

Would anyone with this boat and trailer be able to take some measurements for me? And have some detail pictures of how their boat sits on the trailer?

I would need:
-front and rear width of inside bunks
-front and rear width of outside bunks
-front and rear height of inside bunks
-front and rear height of outside bunks
-distance from rear of trailer to lower hull support
-distance from rear of trailer to front upper hull support

This will help me with making some modifications to the trailer, it's going to be a pain in the rear but a new trailer would cost me 5k, this will just take some time.

Here are pics of the trailer (It's also only a single axle......) do you think I'm nuts?



Here are some pics of how my boat sits on it, you can see at the front it's all kinds of wrong.





Jeff Lyman
02-03-2011, 07:54 PM
Jay no big deal, I dont have measurments for you but believe me I've built or modifyed everything it seems. First figure out how far forward the boat should be and mark how far the bow stop is from the hull. This up to you and has most to do with tonque weight and your tow vehcile. Does not matter if the rear bunks stick out who cares. You need a grinder to cut the welds on the bow verticle post and mig weld it in the new location. The bunks look close, I would say if 80 to 90% of the bunk is touching the boat leave it alone, hell of alot better than rollers! If not cut the weld on the flat stock to the trailer frame and with a jack lift it to the location it needs to be in and reweld. I would tack weld everything with the boat on then remove for final finish.

Your lucky black is easy to match and spray to repair the weld burns yourself. If you want a nice job take it to a body shop shouldnt be much. Complete job 4 to 6 hours. I would of done the same thing you did good move.

Fyi I put a clear roller at the top of my trailer to bow its much easier than that grey holder that just binds up. Nice clean looking boat its my colors black and white!

02-04-2011, 02:09 PM
Thanks for the advice.

What would be a good way of checking there the best position the boat should be on the trailer? I would imagine it would be the engine at or a little behind the wheels? I guess I could use some kind of scale on the tongue somehow for that?

I'm not too worried about cutting/grinding/welding that's the easy part, and it sounds like it's worth doing so I'll tackle that once the snow is gone :)

As for the roller at the top of the vertical post, after putting the boat on the trailer twice last year I switched that orange lower roller in the pics to the top since that grey thing is a POS. Works out MUCH better.

02-04-2011, 06:48 PM
You'll have to weigh the tongue of the trailer, and adjust boat position until it's approximately 10% of your boat weight.

First hit on google (http://www.titantalk.com/forums/titan-towing-hauling/44441-tongue-weight-how-really-measure.html)

02-07-2011, 09:58 AM
That's awesome! Thanks! I don't imagine it will be easy to move the boat around on the trailer to get it right but I'm sure once it's at the right spot it will have been worth it.

02-07-2011, 10:17 AM
Spend an hour at the boat launch. Get it level after laoding and check tongue weight. I'd be looking for 3-400lbs tongue weight witha single axle and a Prostar with a full tank of gas.

02-07-2011, 11:55 AM
Unfortunately boat launch will be tough, I need to reposition the vertical upright anyways so I think I would be ok using jacks on the boat and moving the trailer a little at a time until it's just right.