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#560124 - 04/26/15 10:43 PM anyone ever tried fo float a trailer?  
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Frantically Relaxing Offline
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Out of desperation due to lack of water, I'm giving it serious thought...

The problem- Our SkipperLiner has been in the water for 4 years now. Needs to come out for some bottom and drive maintenance. However, I'm a man with 4 boats and a really cool 3-stage snowblower, and ma nature don't want me to play with any of 'em. Last winter sucked, and this winter (water year officially ends April 30) will be the worst on record for mountain snowfall. I backed the trailer down the ramps a couple of times last year, when the harbor was about 5-6' deep behind the ramps. Could only get the trailer down about halfway before the bumper buried itself in mud. The water's only come up about a foot since then, and it's only going to come up at best a foot more, but even that's just hoping.

Been trying to think of ways to lower the front of the trailer. After doing some engineering, I've come to the conclusion that unless the front of the trailer is on the ground, it's not going to help much.

SO- if lowering the front of the trailer won't help, the next logical solution is to raise the back!

This was discussed amongst our 'boat gang' last summer, and what got brought up was 55 gallon water barrels. The problem with those is, I don't have enough ground clearance.

So I did a little more engineering today... (uh oh)

First, I've estimated the trailer to weigh somewhere around 7500#. Since the front of the trailer is supported, I'm assuming the rear of the trailer will weigh roughly half that, and shouldn't be more than 4000#...

Sound about right?

And oh yeah-- last summer, in a feeble attempt at a fix, I bought and mounted up a 3500# mobile home axle, right in front of the bumper. Good idea, if the lake bottom was anything close to a "solid" substance. Those tires just stuck in the mud like the bumper...

That said-- Between that axle and the main axle I THINK I have at least 6' of space- if not, that axle can come off in 10 minutes- plus 8' of width available, with around 23" of space between the ground and frame...

And out in our harbor's north 40, is a couple of huge chunks of solid floatation foam. I think the one is like 10' x 8' x 2' or so- a little worse for wear but useable...

According to the internet smile - 4000# of water takes up 110,720 cubic inches of space. And a piece of foam 72" x 96" x 18" (perfect fit), comes to 110,592 cubic inches...

The pale yellow/black outlined represents the foam- The boat only draws 10", if I could get it to where the bunks set about 6" under water, it would be perfect!




--to the upper right are the foam blocks, with a buncha junk sitting on the smaller piece...




--so, do-able?


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#560126 - 04/27/15 07:46 AM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Lowrider78 Offline
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Actually, to "float" the trailer IN the water (not "on top of" it), you don't have to ballast it's entire weight.

A metal object that is in the water, has already displaced whatever water it's volume occupies.

IIRC steel/iron, only weigh something like 60% of their actual airborne weight when they are immersed in water.

This means salvage of an object (from an engine block to an entire boat, to a sunken log) requires much less lifting power UNTIL you get to the water's surface.

What it seems to me you are wanting is slightly more than "neutral" buoyancy, floating AT the surface, mostly completely submerged. This lowers your ballast needs.

It's early, I need a shower and breakfast before work, so hunting the math to justify this isn't happening by me now, my thoughts.


That streak that howled by? That was me. Did ya like the roostertail? Big Blocks and Jets Forever
1978 Hawiian 20' Bowrider, 454, Dominator pump
1990 Magnum Mach 1 24' Cuddy Cabin Cruiser, 454, Bravo 1 drive.
1993 Suburban 454 tows the Mach 1 to water.
2001 Blazer 4x4 4.3L gets the Hawaiian wet.
#560128 - 04/27/15 04:53 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Dave R Offline
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I would do some foam on each side and tank in the middle. The tank would need a hole in the bottom to let water in and a hose at the top that runs to the front of the trailer where you could control the amount of air that the water will push out. This wou8ld let you get just the right amount of buoyancy. I'd put an air hose fitting on the valve in case you need to add air too. That said, an under-size block of foam and a some cradles to add more foam blocks with a little trial and error would work too.


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#560129 - 04/27/15 04:55 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Frantically Relaxing Offline
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I'm aware that the trailer's displacement will reduce buoyancy needs. If I spend a few minutes I could come up with a close estimate of what the trailer will displace...

My thought is to over-float it and just remove foam until it sits right, which would be IMO when the bunks are just underwater. Hanging a few buckets of rocks off the bumper will be easy enough as ballast.

The three times we've loaded the boat on this trailer, the stern has never been close to centered-up to the trailer. Nor have we ever been able to use about 5' of the FRONT of the trailer. With the trailer floating it will be piece o' cake to back it down far enough to use those 5', and I'll be able to center the back of the trailer to the boat with just a couple of ratchet straps.

--at least, I hope... wink


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#560130 - 04/27/15 05:04 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Dave R Offline
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The specific gravity of steel relative to water is 7.82 meaning steel is 7.82 times more dense than water (at 39 degrees F) so the 7500 lb trailer would feel like it only weighs 6540 lbs when submerged.


"Mischief Managed"
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#560131 - 04/27/15 05:20 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Frantically Relaxing Offline
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Dave, you posted up while I was typing my last post--

Good idea on the tank, and I do have room for one or two 55 gallon water barrels...


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#560132 - 04/27/15 11:21 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Boise, ID
A crane?


James
2002 Cobalt 226 VP 8.1GIDP
2007 Chevy 2500HD Crew Cab Duramax
1988 Suburban 3/4 Ton
2000 Subaru Forester


#560133 - 04/27/15 11:32 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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MarkHB Offline
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You mentioned that last year the rear of the trailer buried into the mud when reversed down the ramp. Once the houseboat is loaded onto the trailer with the extra buoyancy , will it do the same before you have a chance to pull it out?


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#560135 - 04/28/15 09:01 AM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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tpenfield Offline
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A couple of points . . .

I get 124,416 Cu In from a block of foam 72x96x18, but that would be more in your favor. Like Dave says, figure some buoyancy from the steel and the tires.

Now the killer . . . So, you float the trailer out and get the boat to ride up on top of it forcing it down . . . the trailer may get stuck in the mud as it is forced down by the weight of the boat, given that you will have to pull the boat up on the trailer enough to securely pull it out . . .

I'm not sure, but it might put the trailer in a position that you found when you first tried to pull the house boat out.


Last edited by tpenfield; 04/28/15 09:02 AM.

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#560141 - 04/28/15 07:47 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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GoFirstClass Offline
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Kevin, is there anyone on your lake with a Travelift?


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Anchor's down......Bottoms Up!
#560144 - 04/28/15 08:30 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Frantically Relaxing Offline
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I actually calculated 16" thick to come up with 110,592... I probably typed 18" by mistake!

As for sticking in the mud-- shouldn't happen...

this is a bit rough, but everything is actually drawn to scale...

Here's the current situation, coming down the ramp, which is 8.5° btw...




This is what's happening, once the wheels drop off the ramp. I have some skids on the trailer in front of the tires that aren't shown, but they're just to help get back up over the ledge. Anyway, the bumper hits the mud, and the trailer will only go so far back. It doesn't actually get stuck, it just gets to the point it won't go backwards any farther. It's always moved forward just fine--




Pretend the wheels up front are those of my congear, which will be connected up, to let me get the trailer down farther. It's going to have 19" tires/wheels on it instead of the 24.5"ers, so the front will be lower. The houseboat only draws 10" of water, and I've drawn the back of the trailer 10" below the water surface. FWIW, the tops of my bunks are 31" off the ground. I don't see any way for the boat to stick the trailer into the mud...?



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#560149 - 04/28/15 10:19 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Frantically Relaxing Offline
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Travelift? I wish! Nothing like that here.

Another thing concerning the floating- Since everything WILL be floating, my plan (hope) is to winch-strap the trailer to the boat out back. If I have any ballast I can remove, that should be pretty easy. My hope is the trailer tires will be above the ramp when it gets that far...

I've considered craning the thing out... We have a 'crane guy', he could do it easy enough, but I'd just rather not. If for no other reason than the money. Should this trick fail to work, I'll be giving him a call. Boat MUST come out soon!

Last edited by Frantically Relaxing; 04/28/15 10:31 PM.

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#560150 - 04/28/15 10:45 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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casualboater Offline
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I was thinking the crane can't be cheap, and it's times 2.


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#560155 - 04/29/15 01:32 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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BToran Offline
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this question should have been asked over the winter, with the obvious answer... it will work just fine if you launch it from a conveyor belt.

a question... with water levels so low, is it a good idea to even be out on the lake? gotta be tons of normally submerged "stuff" just waiting to ruin peoples' boating day.


Bruce Toran
Former Owner of a 1996 Carver 320 Voyager
-----------------------------------------
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#560167 - 04/29/15 09:28 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Lambert Laker Offline
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Nothing useful to add on the engineering side… but I always enjoy your posts. I will be staying-tuned & expecting pics thumb


LL

"Common Sense is not common to everyone"
#560171 - 04/30/15 05:22 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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CMJ Offline
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I floated a trailer once, forgot to unstrap the boat before backing it in. It all floated nicely. Guess that's kinda backwards from what you are trying to do.


Take care,
Chris
06 Monterey 248 LS
#560172 - 04/30/15 06:20 PM Re: anyone ever tried fo float a trailer? [Re: Lambert Laker]  
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Admiral

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Boise, ID
Originally Posted By: Lambert Laker
Nothing useful to add on the engineering side… but I always enjoy your posts. I will be staying-tuned & expecting pics thumb


Video?

In all seriousness, I have nothing additional to add but to say good luck.


James
2002 Cobalt 226 VP 8.1GIDP
2007 Chevy 2500HD Crew Cab Duramax
1988 Suburban 3/4 Ton
2000 Subaru Forester


#560173 - 04/30/15 09:45 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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Brian S Offline
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What about a ski type thing mounted to the bumper so it slides over the mud rather than digging in. Would use foam also


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#560179 - 05/01/15 12:54 PM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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captkevin Online content
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It would be interesting to see the trailer being floated.

Last edited by captkevin; 05/02/15 12:22 AM.

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#560272 - 05/07/15 09:44 AM Re: anyone ever tried fo float a trailer? [Re: Frantically Relaxing]  
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captkevin Online content
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Any updates on the plan?


2004 Rinker 232
2010 Dodge Ram Crew Cab Laramie 4x4
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