Artificial trailer tongue weight

I'm thinking about extending the tongue on the trailer for my 15' trihull. The plan is to replace the 3" square tube tongue with a tube about 3' longer. I already had to move the boat forward as far as I could to get what little tongue weight it has, and I'm pretty sure extending the tongue will effectively decrease it.  If it comes up light would it work just to add some weights to the underside near the hitch?

Just to give you an idea, loaded trailer might weigh 2000lbs and I've got around 100-120lbs tongue weight. I can deadlift the hitch to get the wheel off the ground, but not for long. Tows ok the way it is.

Extending the tongue will reduce tongue weight at the hitch, but it shouldn't reduce stability.  You'll still have the same proportion of weight supported between the hitch and trailer axle relative to what's behind the trailer axle.  And you'll have more distance between the hitch and trailer axle which helps stability too. 

Yeah, part of my brain says that it will be better, part of my brain thinks about levers... and I get lost. 

Generally with a trailer, stability is mostly a matter of having more weight forward of the axle than behind it.  Actual weight on the tongue isn't really a concern, it's just a rule of thumb to go by. 

If excessive tongue weight weren't a problem, you could make the world's most stable trailer by just putting the axle(s) all the way at the back and having all of the weight between the axle(s) and the hitch.  That gives you very little weight behind the pivot point (axles) to cause sway, etc. 

If you have a trailer spare, mount it up under the tongue closer to the hitch.  Fundamentally extending the tongue that amount shouldn’t make it any less stable. If you go too far it can get floppy. 

If you extend the tongue, is there room to scoot the boat forward another 6" to compensate?  That's exactly what I did.  I had a 19' boat on a trailer that was really designed for a max of an 18' boat.  The bow was really close to the tailgate and the winch tower was close enough that I couldn't open the tailgate.  I extended it about 2' and re-installed the winch tower about 8" forward.

My current trailer also has the option of moving the axle back.  It's a torsion axle on an aluminum I-beam trailer frame so it attaches with big U-bolts.  I just loosen the bolts and slide the axle where I want it.  Well... truth be told, all trailers have axles you can move, its just a question of if it needs a torch and welder or a 3/4" socket.

Two things:

Consider replicating a folding tongue as an easy way to extend but let it fit in the same space it fits now.

A lot of boat trailers are set up so the axle assembly can be moved around to compensate for outboard motors.  Any chance your axle can be moved rearward?

I don’t think extending the hitch will reduce tongue weight but it would increase your leverage to lift it so it would feel lighter.  

It would actually increase it. Unless I’m missing something obvious. 

In reply to jfryjfry :

It would decrease. The moment created by the weight of the boat in this scenario is constant. Extending the length of the support reduces the support force since you divide by the new, longer, length. 

Responses in no particular order.

The spare is up front but it's light. This is a small trailer. 

Boat is as far forward as it can be, the foot on the motor is almost bumping the rear cross member. 

Axle is welded in place. I could cut it loose and move it but the whole rig isn't really worth that much trouble. If its THAT bad I'd probably hunt down a replacement trailer. A slightly larger galvanized or aluminum trailer would make me happier towing 3+ hours to the coast. In the early 70s their idea of trailer construction was narrow and tall with thin metal. I've never had a problem but....

I thought about folding tongue but room isn't really an issue. I might go that way if I add up cost vs new steel and it's a break even. Assuming I have some scrap stock I could use for the small extension past the hinge.

Here's a photo of the rig in question:

The boat sits high enough on the trailer that I have to get the tires pretty wet on some ramps. Mostly I'd just like to keep the new truck out of the water especially the salt. We're probably trading up next season so I dont really feel like completely reworking the trailer to lower the boat, plus manual tilt might make a lower trailer a PITA.

ultraclyde said:

 The plan is to replace the 3" square tube tongue with a tube about 3' longer. 

How about 34" of trailer tongue extension?

Probably not perfect for "on-road" use in your situation but when you get to the loading ramp lot, on flat ground, add this into the equation and now have your trailer temporarily almost 3 feet farther behind the truck.  

Can you lower the bunks to get the boat closer to the frame, and therefore closer to the water so you don’t need to back in as far?

In reply to John Welsh :

At $134 for that it's cheaper to buy the steel and extend the trailer!

In reply to Sonic :

As mentioned above, I'd probably just buy a used trailer if I was going to do that much work. The trailer is narrow and not built that well. Lowering the boat is also a PITA because the outboard doesn't have power tilt. It clears the ground in the down position now but wouldn't if I lower the boat. Wrestling that thing down while launching would suck. Also, probably selling the boat next year, so the level of work and money I'm willing to throw at the trailer is limited.

Extend it and take it for a spin. My 17' Keywest only has 75# of tongue weight and it tows fine all the way up to interstate speeds. 

If it's stable, it has enough tongue weight. 

Looking at how that's proportioned, I'll bet it'll tow just fine with the longer tongue and no other changes.  

yes you can add weight, i've done before to a swaying trailer. the further forward the better but your problem could be fixed just by putting some stuff in the front of the boat. 

Super GRM idea... strap a cinder block to the tongue.  I'm half joking, but it's more acceptable than putting a dead hooker in the bow.  I did use this idea for a bit.  I bought a 19' boat without a trailer and took my own trailer to pick it up.  The tongue weight was about negative 25 lbs after we loaded it.  Three concrete blocks in the bow got me home OK.

But honestly, what about making your extended tongue from some really heavy gauge steel?  Stash the anchor and some of your cargo up in the bow for transport to help until you sell it.

I know you mentioned manual tilt, but if you tilt up the motor (either the whole way, or just use the highest trim pin hole) you might get the possibility of another 6" forward.   I know the hernia-inducing things an outboard can do, but you could leave it down, load and pull the boat, grab the skeg, lift it to a higher trim, then give a few more cranks on the winch.

extending the tongue and leaving the boat in place will actually increase the weight on the tongue. The lever may be longer, but it is heavier by the amount of steel you added. The longer trailer will also be more stable as it will take more force to induce sway.

If you are interested in moving the trailer forwards.. cut the rear crossmember out and move it fowards a foot.

twowheeled said:

yes you can add weight, i've done before to a swaying trailer. the further forward the better but your problem could be fixed just by putting some stuff in the front of the boat. 

I once strapped 750# of gravel bags to the front of my trailer deck and the spare tire and winch battery directly to the tongue.  It worked.  

In this case i’d probably make a small steel box that will hook over the tongue like saddle bags and dump something heavy in it like some concrete or a bucket of wheel weights or a small child

mad_machine said:

extending the tongue and leaving the boat in place will actually increase the weight on the tongue. The lever may be longer, but it is heavier by the amount of steel you added. The longer trailer will also be more stable as it will take more force to induce sway.

This would only be true if the steel was proportionally heavier than the weight it balanced.  Simply adding tongue length adds a little weight to the tongue, but it has to be compared to the weight of the whole thing.  If you're towing a 10,000 lb load and add 2 feet of tongue length that weighs an additional 8 lbs, the tongue weight will decrease because the length of the lever has increased proportionally more than the additional weight you added with the longer steel.

I have a similar problem with my tow dolly. I can hitch/unhitch the tongue easily by hand with a car on the dolly. It's a bit unstable on the highway, especially braking. I can't load the car further forward because of the wheel-stop built into the dolly's deck. I really think more tongue weight would help it tow better.

I carry my autocross wheels in the truck bed, so I'm thinking about moving all four wheels to the dolly's tongue. Maybe mount them vertically, like a tower of tires between racecar and my tailgate. I might even build a tray for putting a floor jack on the tongue. Anything for more tongue weight. That dolly is spooky at speed.

How about something like this.  U- clamp it to the extension, add weight as needed.  When you get the new boat /trailer, remove and use it.

https://www.ebay.com/itm/30-Inch-Aluminum-Truck-Pickup-Bed-Trailer-ATV-Tongue-Lockable-Tool-Box-W-Lock-/332432642663

I think I'm going to get 3" square tube in a thicker wall than it currently uses. The stock stuff is THIN, like maybe 16ga?  Stepping up to a thicker stock will add some weight forward of the axle and on the hitch specifically, but it also gives me a solid platform to weld/bolt to. See, I figured out how to add some useful tongue weight to the trailer if needed - Add walk boards to the tongue! That way I can safely and easily walk from boat to tailgate when loading in colder weather. It should add a few pounds, but if I really need weight I can overbuild the hell out of them and add it.

Now I just have to get off my butt and do it.

Problem solved.  Nice when a plan comes together.

...on the back side of the spare.