Differential lock on boat ramp?

[robtmc]

Posting this because of something I saw a few days ago and what I might have read a long time ago about how the center differential lock can help brake function.

In short, wife was backing the boat down the ramp, slightly wet, and we were having trouble getting the boat unstuck. So, I had her go up the ramp, stop, and let it roll back and hit the brakes to let inertia do her thing.

Was working fine, but noticed the passenger side front tire slide while rear kept rolling when she hit the brakes. Did not seem right, so told her to lock the differential (already in 4Lo) and hit it again as the boat had not come loose.

Boat came off fine that time, and no slippage was noted.

What I thought I recalled was the diff lock pretty much made sure all wheels got the same braking force, bypassing any Torsen % magic. Any thoughts on boat ramp braking technique to prevent slippage on some wheels? Was I FOS?

I freely admit to being an idiot and newbie to boat ramps.

 

[BrianSD_42]

Wheel chocks

Wheel chocks

Wheel chocks

Wheel chocks

Yes. A diff lock isn't a bad idea. Not needed though for most ramps. 4LO will be most useful.

I freely admit to being an idiot and newbie to boat ramps.

Yeah dude being a noob isn't a valid excuse for losing your truck in the lake or ocean - if that happens. I'd suggest Youtube on how to safely launch a boat. Youtube is great for this stuff. West Marine has training videos as well.

Just curious how much does your boat weigh?

 

[NuclearN8]

I tow and launch my dad's small wooden fishing boat 4-5 times a year with our 2007 4Runner. On the way in to the ramp, I always turn the dial to 4Hi.
That's all I've ever needed but his trailer and boat combined only weighs 1800 lbs.

If I had something larger and the ramp was shallow (which would mean I had to back down farther to get the boat to float), I would probably drop her in 4Lo and lock the center diff once I had it positioned and ready to back down.

The steeper the ramp the less you have to back down to get the boat to float and in some cases the rear tires don't even need to hit the water at all which means traction isn't an issue.

 

[4by4th]

I've pulled a 20 foot fiberglass center console bay boat with my 2004 4R since new and always put it in 4H when I start backing up toward the ramp. The only time I've ever used 4L on a boat ramp was prior to the 4R with a Nissan P/U and 16 foot aluminum johnboat when the trailer seemed to be stuck and wouldn't budge to pull out of the water. Ended up bending the trailer axle spindle 45 degrees sideways as the wheel had apparently gone off the concrete under water. If you ever think you need to use 4L on a boat ramp you need to figure out what is wrong and fix that instead.

 

[robtmc]

The 4Lo is not for the pulling power, it is for the better throttle control we get in the parking area that is covered with broken up lava rock. Hard to get the rig rolling smoothly in 4Hi until you give it gas, then it lurches. Lo starts much smoother. Just better control on the crunchy surface. We have pulled it out in 4Hi, that is not the issue.

Boast and trailer are likely in the 6000+ range.

 

[WI_4Runner]

From what I gather, your issue is getting the boat OFF the trailer while launching? I don't know whether you have a bunk or roller trailer, but you likely are not backing your boat/trailer into enough water to accomplish this. This isn't really a tow vehicle issue. Back up a little further and your should be able to free the boat from the trailer easier.

While sometimes I do use the "slam on breaks while in reverse to pop the boat off via momentum" trick, I have launched & retrieved boats for 25 years and would suggest you get some experience prior to using this method. I've seen boats dumped on the ramp above the water line, and trucks in the water as a result. Take your wife and the boat to a safer launch and get some repetitions in. Videos are great for starters, but you need to practice as well.

I slide almost EVERY time I slam the breaks backing down, sometimes a few extra inches, sometimes a few feet further - it's impossible to expect that your going to stop on a dime with a load in tow on a launch. Throw any sand, water, slime, seaweed etc into the mix, and tire slippage backing down/applying breaks or tire spin pulling up the ramp is common.

Ramps are slick and between sand, water, slime, seaweed, tire spin is not uncommon either backing down & applying breaks or pulling up the ramp. This sounds like a very greasy launch, I would suggest you and your wife get some practice runs in on a safer ramp.

I drive a SPORT V8 - I have full time 4WD, but dropping into 4wd on your rig or using lower gears to pull up the ramp are all good pieces of advice.

Don't forget to use your Parking break!!!!!

If you are slipping while applying breaks backing DOWN the ramp, you need to look at your tires, how heavy your load is, and what sort of ramp you are working with.

If only you were in Seattle, I'd be happy to take you out and show you how I handle launching with my boat and 4Runner on some unimproved launches.

 

[ThorInc]

I pull a bass boat and trailer probably 4000+ lbs. Lo4 on occasion never needed the locked RR diff, ever.

 

[robtmc]

From what I gather, your issue is getting the boat OFF the trailer while launching? I don't know whether you have a bunk or roller trailer, but you likely are not backing your boat/trailer into enough water to accomplish this.

Bunk trailer. Going in until the rear wheels are just touching the water. Am starting to look at how the dealer set up the trailer for possible friction issues causing excessive drag.

I agree, the momentum method seems like a touchy work around, not optimum. Did buy a 18" hitch extension to get the trailer deeper while keeping the rear wheels of the truck out of the water. Got some practice to do yet figuring out why the boat does not want to come off the trailer more easlily

 

[WI_4Runner]

Bunk trailer. Going in until the rear wheels are just touching the water. Am starting to look at how the dealer set up the trailer for possible friction issues causing excessive drag.

I agree, the momentum method seems like a touchy work around, not optimum. Did buy a 18" hitch extension to get the trailer deeper while keeping the rear wheels of the truck out of the water. Got some practice to do yet figuring out why the boat does not want to come off the trailer more easlily

A lot of variables here in play ---- trailer length, slope angle etc.....

Rear wheels being your TRAILER or VEHICLE wheels? My launch @ low tide I occasionally have to get the rear wheels wet and in some cases at super low tide, the front wheels even get some water when it really shallows out.

What sort of boat are we talking about? You can slicken up the bunks... You can go cheap and spray car wax or pledge furniture polish on the carpet bunks, or you can go more permanent and install bunk slicks. Forewarning here - DO NOT unhook the boat until the boat is IN the water, these methods can make a bunk trailer equivalent to a roller and you WILL dump your boat on the ramp

Another thing that can help is to wet your bunks prior to launching --- if the launch has a hose- shoot some water on them, or back down a foot or two further, then pull up to a safe level to proceed with launching off the trailer....

Every boat, trailer, and launch is different as they all are interconnected, but generally you are looking to back your boat down to the point where your boat is just barely floating but still guided/controlled by the bunks...

 

[robtmc]

Truck rear wheels. Tide does not vary much here but do not want the rears down where it does get a bit slippery.

Read about silicon spray on the bunks after drying a while, totally forgot to remind the wife to do that when she went and got the trailer last time we were out.

Boat is a 23' power catamaran. We are definitely getting in deep enough to float the back, just too much friction to be able to pull it off with the bow and stern lines.

I am looking at how the dealer set up the side guides/bunks to see if they are gripping the boat too tightly.

 

[WI_4Runner]

Truck rear wheels. Tide does not vary much here but do not want the rears down where it does get a bit slippery.

Read about silicon spray on the bunks after drying a while, totally forgot to remind the wife to do that when she went and got the trailer last time we were out.

Boat is a 23' power catamaran. We are definitely getting in deep enough to float the back, just too much friction to be able to pull it off with the bow and stern lines.

I am looking at how the dealer set up the side guides/bunks to see if they are gripping the boat too tightly.

That's a big boat for a V6 4Runner - what is the weight? Catamarans are trickier to launch, and I think that is what your experiencing, as there are two hulls essentially, hence double the amount of bunk friction.

I would try backing in a shade deeper - put it in 4wd and you should be able to manage having your rears slightly wet. Wouldn't hurt either to slicken up the bunks (they do make a dedicated silicone spray for this that I've seen on Amazon) or learning how to power on/off the bunks with your boat motor.

 

[4by4th]

MaryKate Liquid Rollers Trailer Bunk Board Lubricant https://www.amazon.com/dp/B00144EZJ8/ref=cm_sw_r_awd_eygtwbSZ4YFR6

This will help. Start with a little., don't soak the bunks with it. As mentioned earlier, don't unhook your winch strap until the trailer is backed into the water or you might drop the boat onto the ramp.

I usually back my boat in until the front of the boat is near the water edge, unhook the winch strap, climb into the boat, motion to my wife or son now driving the 4Runner to back up with my slow hand motion until the motor has enough water, hold up my hand so they stop, start up the boat motor, put the boat motor in reverse, motion with a with a faster hand motion to back up a little faster, then make a fist so they stop quickly releasing the boat from the trailer. All boats and trailer combos are a little different, if we back mine in too far the bow lip hangs over the winch roller, especially on steep ramps. I've never had my 4R tires slip, but my rig weighs half of what yours does. Does your trailer have brakes? A boat and trailer in the 6000 pound range should have trailer brakes.

 

[robtmc]

Just did a couple things to the trailer after thinking about various helpful replies. The bow roller tip might be a key: I have noticed when winching the boat in that it had to bump up over the roller. So, I lowered the roller an inch or so. Really wish EZ-Loader offered a catamaran stop like others, a roller on a cat is a kludge. Dunno if it was hanging things up or not.

Also, the port side guide/bunk was set up quite tight against the side of the boat. This could have been causing friction resisting the boat sliding back. Loosened the guide and eased it out so there is just a touch of space as on the other side.

Have some heavy duty CRC silicon spray on hand. If the boat does not come off easy next time without any momentum jiggery-pokery, will have the wife give the front 1/2 of the bunks a good spray before the next retrieve. Leery of the slipperiness I read about. Already do not unhook until the bow is over the water edge.

 

[AKmoney]

If you turn the center diff lock on you'll lock the front and rear axles together at the same rate but you could still get a side-to-side variation in wheel speed. The front diff is open so it's physically possible for one front wheel to turn while the other is stationary. I'd imagine ABS would try to "unfreeze" the frozen wheel but there could be other factors at play.

BTW, I've used my 4Runner to launch (and retrieve) a 25' deck boat in and out of Lake Havasu. I put it in 4Lo (with no diff lock) and it practically idled the boat out of the water. Note: I only had to tow the boat about 1/2 mile. Not sure I'd recommend towing something that big and heavy over longer distances.

 

[Cricoid]

I don't know how you guys pull big boats with the 4Runner. I tow my Kawasaki Mule on a small trailer a few times per year to go hunting....it is like I'm pulling a 747 on uphill stretches. Not fun on long trips.

 

[ThorInc]

Bunk trailer. Going in until the rear wheels are just touching the water. Am starting to look at how the dealer set up the trailer for possible friction issues causing excessive drag.

I agree, the momentum method seems like a touchy work around, not optimum. Did buy a 18" hitch extension to get the trailer deeper while keeping the rear wheels of the truck out of the water. Got some practice to do yet figuring out why the boat does not want to come off the trailer more easlily

Are you saying the rear of the boat does not float up and off the rear bunks some when you are launching it? If so you might just have the boat slightly too far forward on the trailer. Do the rear bunks extend beyond the boat hull itself?

Edit: Just read more of your posts, silicone spray will work just don't unclip the strap until your rig is right at the end of the ramp and partly in the water. You can also wax the runners but go easy putting it on.

 

[WI_4Runner]

Are you saying the rear of the boat does not float up and off the rear bunks some when you are launching it? If so you might just have the boat slightly too far forward on the trailer. Do the rear bunks extend beyond the boat hull itself?

Edit: Just read more of your posts, silicone spray will work just don't unclip the strap until your rig is right at the end of the ramp and partly in the water. You can also wax the runners but go easy putting it on.

In almost all cases you want the bunks to be extended a tiny bit past the end of the boat hull to provide support of the heaviest part of the boat - the transom....

This wouldn't be the culprit for said problems either. There may be some bunk issues at play but would not stem from an extra inch or so of bunks.

Catamarans just seem to be stickier on the hulls - silicone spray is the temporary/cheap fix, bunk slicks would be the next/most permanent step!

Also - how steep of a launch is this?

 

[ThorInc]

Be super careful with slick bunks......they can create many other issues, lol.

 

[robtmc]

No idea how to tell how "steep" these ramps are, this is the first time for me, still feeling my way along. When we did a checkout drive of the boat with the dealer, the truck they used to launch did have to do a momentum launch after the stern was deep enough to start the engines, FWIW.

So it would seem I have a trailer issue. The stern is definitely floating, was on the dock between ramps watching. Front end looked like it was starting to float, but no rearward motion. may tell the wife to get out and get her feet wet to give it a shove.

Too paranoid to unhook anything until into the water, so if I do use silicon spray, hope I got my butt covered there. Dead level ground towing other than the ramp and short distance, no worries about hills. Hoping technique will avoid needing spray.

 

[4by4th]

Don't be afraid to use some spray on the bunks, just be aware as you already are. If you don't already have some type of transom straps you might consider adding them for towing to keep the back of the boat tied to the trailer, although I've heard some people say they'd rather the boat come off the trailer in an accident - not me.

You should post some pictures.