Today’s task - adjusting and balancing our boat trailer

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.

Pretty ironic that you are posting this today. We bought a new to us boat in August that came with a brand new 2016 Venture trailer (more irony...). So the first time this trailer was on the road was when I towed it for the sea trial. Mine is the opposite and I was just going to email Venture this morning. Mine is pretty much identical to yours but my bow stop is behind the V where yours is in front of it. My bunks stop about 6" in front of the transom so the transom is not supported by the bunks. My first thought was to move the bunks back (by unbolting them and drilling new holes in the bunks). I have no room to move my bow stop forward because of the side beams creating a V. The only way I can move mine is to move it in front of the V like yours is. The problem is we have no truck scales near here to check it with as far as I know. The good thing is we don't tow very far and speeds are slower so I could test then move then test again.

Either way let me know how it goes. Did your trailer come with the bow stop in front of the V like it is? Has Venture said anything about what steps to take?

If you do any serious towing with that, can you also do a write up on the transmission rebuild on the Equinox?

boatman37 said:

Pretty ironic that you are posting this today. We bought a new to us boat in August that came with a brand new 2016 Venture trailer (more irony...). So the first time this trailer was on the road was when I towed it for the sea trial. Mine is the opposite and I was just going to email Venture this morning. Mine is pretty much identical to yours but my bow stop is behind the V where yours is in front of it. My bunks stop about 6" in front of the transom so the transom is not supported by the bunks. My first thought was to move the bunks back (by unbolting them and drilling new holes in the bunks). I have no room to move my bow stop forward because of the side beams creating a V. The only way I can move mine is to move it in front of the V like yours is. The problem is we have no truck scales near here to check it with as far as I know. The good thing is we don't tow very far and speeds are slower so I could test then move then test again.

Either way let me know how it goes. Did your trailer come with the bow stop in front of the V like it is? Has Venture said anything about what steps to take?

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Hey Boatman,

My trailer came from Venture with the post it its current location. I’ve done no adjustments so far.

The trailer also came with these U-bolt double hole spacers. With the three position bracket only needing two U-bolts, and the spacers, you can move the post over the aluminum I-beams if needed.

Furtinatly for me, I expect my U-bolts will be behind the aluminum I-beams when I’m done with this task later today.

PS: another boat trailer brand that starts with the letter P and rhymes with Yhoenix will adjust the trailer for you....for an extra $800. ...... right ..... I’ll do it myself thank you.

PPS: Yes, I spoke to someone at the factory.

PPPS: I hope to make another video about this process. There is no one universal agredded upon process to custom fit a boat trailer. This is one of those things where people have a strong opinion.

PPPPS: Your described 6” hull bottom overhang is within the 0” to 12” overhang Sea Ray recommends for their trailer boats. Think of your boat on a roller trailer. The last trailer roller needs to be at a very minimum 4” under the bottom of the hull away from the transom, never directly under the transom to avoid transom stress cracks. Can you post a close up photo or two? You may be good to go now. My goal is 4” boat hull bottom overhang past the bunks.

Personally, my opinion is the only wrong way is one that results in a dangerous tow setup, including too much or too little tongue weight or being outside the tow vehicles manufacturer specified limits.

Espos4 said:

If you do any serious towing with that, can you also do a write up on the transmission rebuild on the Equinox?

Click to expand...

It’s a Chevy so it can do anything, right

Seriously, that was just to get my trailer home. I will not be using a Equinox to tow my boat.

I’ll go over my tow vehicle someday, but I will save that for a different day so I can carefully choose my words. Some people get very opinionated about tow vehicles. In brief, I’m using a truck and I’m well within the manufacturers specifications, as well as being compliant with my local states ripoff fees for the plates on the tow vehicle and trailer license that charge a premium due to weight.

Locally to me is a race track. The “wonderful and loving uniformed pease keepers” randomly and frequently set up portable scale systems then check everything you can image to help keep us safe and if we are unsafe, use fines to help encourage us to get safe ;-)

I’ve never been ticketed but became concerned when I was told all the different ways these peace officers help keep us safe during these random road side checks as they try to find a violation; truck plus trailer over weight by truck manufacturer spec, truck only weight with trailer attached over weight by truck manufacturers spec, truck overweight by truck license, trailer over weight by trailer license, trailer over weight by trailer spec, trailer over weight by tire spec, tongue over weight by hitch ball spec, trailer over weight by hitch receiver spec, trailer over weight by tow vehicles manufacturer spec, trailer over weight by trailer breaks weight rating, trailer over weight by hitch spec. Those ones come to mind, but there could be more. If you have a light bulb burnt out, or didnt criss cross your safety chains under your hitch, well, get ready to make a forced donation.

Heard of one officer yelling at a person because as they were in the long queue waiting to be weighed took a pee. Why couldn’t they take a pee? They were told they were reducing weight before they were weighed. Really? I mean REALLY? So you need to do medical damage your bladder? C’mon.

I don't have those spacers. What do they do? The previous owner didn't have a trailer for the first few years then in April they bought this trailer from the shop they stored the boat at. They admitted they were tired of dealing with her (and I believe that after we dealt with her in the purchase process). They wanted nothing to do with her or the boat so I'm guessing they just lifted the boat up and sat it on the trailer and it sat like that until we bought it.

Interesting about SR recommending the boat hang over the bunks. I would have never thought that. I'll have to ask Crownline about their recommendations. If that is the case then mine should be good as is.

One of the issues I have is the anchor locker scupper location. When I winch the boat up it rolls over the roller and flexes and pulls. Not much I can do about that except for moving my winch higher but don't think I can do that because it will move the boat further back on the trailer.

Here are the only pics I have now:

Boatman, you are using a spacer now. The spacers allow your post to partially overlap the I-beams.

ok. I see that now. I can only move my post forward about 1/2" or so or move it in front of the I-beams, which would be about 8" or so.

I'll wait until I hear from Crownline before making any adjustments but update me on how yours goes.

boatman37 said:

ok. I see that now. I can only move my post forward about 1/2" or so or move it in front of the I-beams, which would be about 8" or so.

I'll wait until I hear from Crownline before making any adjustments but update me on how yours goes.

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Will do Boatman

Just looked at mine and I do have a little adjustment. Didn't realize there were 3 sets of holes in the bow post. My front one is in the very front set of holes. Moving my post forward will move it about 20" forward (way too far). If I use the middle set of holes instead of the front set then I can move it forward about 3". Not enough to get the bunks to the end of the transom but closer. But this would allow me to move my bow roller higher to get it away from the anchor locker scupper. Doing that will move the boat back about 3" due to the different angles between the bow rise and the angle of the bow stop post.

boatman37 said:

Just looked at mine and I do have a little adjustment. Didn't realize there were 3 sets of holes in the bow post. My front one is in the very front set of holes. Moving my post forward will move it about 20" forward (way too far). If I use the middle set of holes instead of the front set then I can move it forward about 3". Not enough to get the bunks to the end of the transom but closer. But this would allow me to move my bow roller higher to get it away from the anchor locker scupper. Doing that will move the boat back about 3" due to the different angles between the bow rise and the angle of the bow stop post.

Click to expand...

With full disclosure that this is my opinion only, you never want the winch strap pulling the boats tow eye up or down. You want the winch strap to run parallel to the frame of the trailer.

That being said, if I owned your boat and trailer and I was adjusting your trailer for your boat, I would lower the winch about one inch.

iBoat Skipper Doug said:

That being said, if I owned your boat and trailer and I was adjusting your trailer for your boat, I would lower the winch about one inch.

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FYI... Once the boat is pulled further/properly onto the trailer (bow eye should tuck right under the bow roller to "lock" the bow in), the strap should be level.

The boat was slightly further forward before but we had flooding and had an assembly line at the marina pulling boats. We had planned on moving it to the upper lot and putting it back in when the water went back down but we decided to call it a season so the boat stayed where it was in relation to the bow roller. The way it was the roller was right against the bow eye. I do have the turnbuckle to pull the front down to counteract the winch pulling up. Not ideal but I'm afraid of the scupper and the possibility the gelcoat cracks because of it.

iBoat Skipper Doug said:

It’s a Chevy so it can do anything, right

Seriously, that was just to get my trailer home. I will not be using a Equinox to tow my boat.

I’ll go over my tow vehicle someday, but I will save that for a different day so I can carefully chose my words. Some people get very opinionated about tow vehicles. In brief, I’m using a truck and I’m well within the manufacturers specifications, as well as being compliant with my local states ripoff fees for the plates on the tow vehicle and trailer license that charge a premium due to weight.

Locally to me is a race track. The “wonderful and loving uniformed pease keepers” randomly and frequently set up portable scale systems then check everything you can image to help keep us safe and if we are unsafe, use fines to help encourage us to get safe ;-)

I’ve never been ticketed but became concerned when I was told all the different ways these peace officers help keep us safe during these random road side checks as they try to find a violation; truck plus trailer over weight by truck manufacturer spec, truck only weight with trailer attached over weight by truck manufacturers spec, truck overweight by truck license, trailer over weight by trailer license, trailer over weight by trailer spec, trailer over weight by tire spec, tongue over weight by hitch ball spec, trailer over weight by hitch receiver spec, trailer over weight by tow vehicles manufacturer spec, trailer over weight by trailer breaks weight rating, trailer over weight by hitch spec. Those ones come to mind, but there could be more. If you have a light bulb burnt out, or didnt criss cross your safety chains under your hitch, well, get ready to make a forced donation.

Heard of one officer yelling at a person because as they were in the long queue waiting to be weighed took a pee. Why couldn’t they take a pee? They were told they were reducing weight before they were weighed. Really? I mean REALLY? So you need to do medical damage your bladder? C’mon.

Click to expand...

I’m glad my humor didn’t get lost in this post!

I really didn’t think that you had any intention of using that for towing.

iBoat Skipper Doug said:

View attachment 60658

Hey Boatman,

My trailer came from Venture with the post it its current location. I’ve done no adjustments so far.

The trailer also came with these U-bolt double hole spacers. With the three position bracket only needing two U-bolts, and the spacers, you can move the post over the aluminum I-beams if needed.

Furtinatly for me, I expect my U-bolts will be behind the aluminum I-beams when I’m done with this task later today.

PS: another boat trailer brand that starts with the letter P and rhymes with Yhoenix will adjust the trailer for you....for an extra $800. ...... right ..... I’ll do it myself thank you.

PPS: Yes, I spoke to someone at the factory.

PPPS: I hope to make another video about this process. There is no one universal agredded upon process to custom fit a boat trailer. This is one of those things where people have a strong opinion.

PPPPS: Your described 6” hull bottom overhang is within the 0” to 12” overhang Sea Ray recommends for their trailer boats. Think of your boat on a roller trailer. The last trailer roller needs to be at a very minimum 4” under the bottom of the hull away from the transom, never directly under the transom to avoid transom stress cracks. Can you post a close up photo or two? You may be good to go now. My goal is 4” boat hull bottom overhang past the bunks.

Personally, my opinion is the only wrong way is one that results in a dangerous tow setup, including too much or too little tongue weight or being outside the tow vehicles manufacturer specified limits.

Click to expand...

I think there is a misunderstanding when it comes to the stern hanging over the bunks. I don't think SeaRay is recommending that it should hang over, only that if it does hang over it should be within certain limits.

Did some reading up today and every article I read said they should at least be even with the transom and never short?

Seeing that the entire weight of the outdrive and about half of the engines weight is directly on the transom, I prefer to have my stout sturdy bunks under it

boatman37 said:

Did some reading up today and every article I read said they should at least be even with the transom and never short?

Click to expand...

The good news about the internet is you can always find someone that wrote an article that supports any claim.

So I’m not wishing to state what others should do, only what I do.

My bunks were sticking out past the transom edge by 14 inches. Now that I adjusted the bow stop the bunks end 4 inches short of the unusually shaped transom Sea Ray had on these early 2000’s 225 Weekenders.

On this boat, the transom is not flat from port to starboard. The central 1/4th of the transom area with the drive looks like someone cut a piece out about 3 1/2 inches deep. So my bunks end about even with that area, although my bunks are not in that area. I know, this is hard to follow so I need to take and upload a photo.

My goal was 7% tongue weight. Right now I’m 30 lbs over, so 7.4% tongue weight. However the storage compartments in the cabin are empty and that’s my first mates domain. I expect our boat will gain 250 lbs, mostly in the cabin area. This will increase tongue weight, I am estimating, by 1/3 the added weight, or 82 lbs. Oh, plus I need to add the spare tire mount 15 lbs and spare tire 28 lbs near the bow stop so add some more tongue weight for that, lets say 60% of the 15+28 or 60% of 43 or 26 lbs. So I will eventually need to reduce tongue weight by 30 + 82 + 26 = 138 lbs.

After launching the boat and adjusting then trailer to my plan, we ended up going for a cold but very enjoyable boat ride to a local restaurant on the water that was designed to look like a old steam powered paddle wheel. Met another boating couple and talked til twilight. After returning to the boat ramp and loading the boat we still went to a local Cat scale, but we were too tired to retrun to the ramp, launch the boat, readjust the axel carriage, reload the boat, then head to the Cat scale again. As it was, I was so tired that after parking the boat at home I didnt put my tools away, and thats not like me. I’m that guy that can’t stand it if one socket is not clipped into the organizer rail at the end of the day.

Even with the adjustments we made not being totally complete, the boat pulled home much better, smoother, and the back of the truck was not squatting like it was on the way to the ramp. With a 18 inch boat stop aft adjustment, I am estimating I cut the tongue weight down by 800 lbs - 900 lbs. The trailers tongue jack now cranks with normal effort. So I’m estimating on my trailer with my boat, a 1 inche axel movement will result in a 50 lb tongue weight change.

My plan is to move the axel carriage forward 2 inches to slightly reduce tongue weight, but I’ll do that adjustment next time we go boating then head to the Cat scale to recalculate then confirm were good.

So your bow stop is now behind the V like mine now?

I know what you mean about the notched transom. Mine is the same way. The center of the transom about 2-3' wide is 'recessed' into the transom. My bunks are actually about 6" short of this area so probably about 10" in front of the outer areas (but they don't actually support that area).

Buy yourself a tongue weight scale, you can check it anywhere that way. I keep one in my truck all the time.
I moved my winch post forward, had travel lift put boat on trailer with bunks flush with transom, then I just moved my winch post back to the bow and tightened it in place, done. Verify tongue weight. BTW if you have too much tension on the winch cable, it can drastically alter your tongue weight, so check with cable tight and slack to determine what effect if any on your tongue weight. My boat and trailer weigh about 13500 lbs and I run about 650 lbs tongue weight,. My triple axle Venture tracks very well with that set up.