iBoat Skipper Doug
Active Member
- Aug 8, 2018
- 140
- Boat Info
- 2003 225 Weekender w/Bravo III drive
2019 Venture trailer
- Engines
- 5.7 MPI Mercruiser w/Bravo III drive
Today we are working on a interesting task, adjusting and balancing our new boat trailer to a custom fit specific to our boat.
This means all the parts on the trailer that can be adjusted get adjusted to their optimal location for our specific boat then we move the boat’s axel carriage to its optimal location. These adjustments do not come out of a book. They are done like the way a suit tailor fits a suit to your body, one measurement at a time.
Why do this process? A properly adjusted and optimally balanced trailer is safer to tow, easier to load and unload, and gives the best support for the boats hull.
Here is the rub. You use a truck scale to calculate the balance of the boat. The boat can’t be on the trailer as you do these adjustments and some item adjustments affect other items. Oh, also the scale is miles from the boat launch.
With our boat on our trailer, part of our trailer bunks are exposed behind the boat, which means that part of the bunks are not supporting the boat. We need to fix this. We can not move the bunks forward or aft, only closer or farther apart from each other and higher / lower at each end of the bunk, which means we can also adjust the level angle of the bunks. So what can we do? Well, we need the boat to be further back on the trailer. So we need to move the bow stop, along with its post, back about 16 inches on the frame of the trailer. This adjustment changes the center of gravity further back on the trailer similar to how you can adjust your balance with another person on a teeter totter. The rearward post adjustment will reduce the tongue weight. To increase tongue weight without moving the boat stop post from its optimal location, we need to move the axel carriage further back on the boat. See how moving one item affects another?
On a boat this size, the trailer manufacturer recommends keeping the tongue weight not at the typical 10% for cube trailers but between 5% and 7% of total loaded trailer weight to avoid trailer sway, a dangerous situation that can occur during towing at highway speed where the trailer sways back and forth, and in extreme cases, results in a oscillation that increases in intensity until the boat and trailer flip on its side, resulting in a wreck. Too little tongue weight = sway. Too much tongue weight and the back of the truck squats, reducing the weight on your tow vehicles front wheels then the front tires don’t steer very good, possibly resulting in a wreck as your vehicle can’t make a turn on a highway. So, too little tongue weight = wreck, but too much tongue weight = wreck.
The answer to avoid a trailer weight balance related wreck is to have a properly adjusted and balanced boat trailer specific to our boat and that is our task today.
The boat stop post adjustment is one of five items we are adjusting on the boat trailer today.
1) Boat stop post
2) Winch height
3) Bunk width
4) Bunk height / angle
5) Axel carriage location
Each of these adjustments has a logical process to determine its optimal location similar to the one I described above.
So the process goes like this; launch boat at a boat ramp, adjust trailer, load boat, go to scale, weight tow vehicle connected to boat, tow vehicle plus boat, and tow vehicle not connected to boat, recalculate tongue weight, compaire to calculated optimal tongue weight, return to boat ramp and repeat these steps making smaller adjustments each time until we have everting perfect.
Wish us luck.
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