# Building a firefighting trailer



## STOIE (Nov 9, 2014)

Hey all,

Some of you may know I hail from the Snowy region in NSW, Australia which is among the worst bushfire regions out there. So, to help protect things around my woods and to assist during the off season, when burning off.. I have been building a firefighting rig with the old man.

Attached are some pics of what we have so far.

The specs are.. 22ft speed boat trailer (rated 2500kg), bought it fully working except with some surface rust, a bit worse than surface in the guards and in need of some new shackles... but, $500 is pretty sweet. It's got 5" drop axles, which I spun around for 10" of lift... this is a bit of trial and error, if they break I'll know better and buy some straight axles, if they work fine... hooray! We replaced the 5mm thick shackles with 10mm ones we made ourselves and swapped out all the suspension bolts for new stuff.

Next we cut out all the extra crap that made it a "boat trailer", like the winch section, rear drop area for the prop protection, skids (and attachments) and the big side poles for guiding the boat on. We then modified the neck (A-frame) of the trailer with a 10" drop (see the 45 deg section) and welded a new straight section across the back of the trailer.

After that, added some bars across the middle to support the tanks and mounted up the rails that hold the tanks (including one in the middle you cannot really see) and pump. We made a area to mount the battery tray for the pump and a stand for the hose reel. The pump I picked up off ebay from a bloke in northen NSW, was an ex NSW rural pump (Davey Tankermaster). It's twin cylinder 16hp and can flow about 350LPM (~90GPM) @100PSI.... I just had to rebuild the carb (put a kit in it), fix up the dodgy throttle the guy had rigged, buy some storz fittings and give it a general cleanup... now runs well!

We mounted the tanks, by just bolting their bases to the rails... we are currently in the process of doing all the plumbing and will explain that once I have it all done, in the mean time, let me know what you think!

Aaron.


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## MOE (Nov 11, 2014)

Looks great. How big is the tank. One suggestion I would have is to pickup a foam eductor and aspirating nozzle and have some class A foam on hand. It will make your water go a lot further on wildland fires.


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## 2dogs (Nov 11, 2014)

How big are the tanks? The tongue looks to be pretty long for an off road trailer. A bit on the week side too. Yeah add a foam tank when you can. Build quality looks good. Fire trailers are cheap in the winter time here. The postage would be a bit much to send one to OZ.


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## STOIE (Nov 11, 2014)

Hey guys,

The tanks are two 1000L IBC's. (2000L total, for the most part it will probably only carry 1000-1500L though).
Yeah the A frame/tongue of the trailer is longer than I would have liked, however, there would be way to much work in changing it as I would need to cut out alot of steel and replace it.
The hitch is interesting, it goes inside the tube with the master cylinder inside the unit, it's the first I have seen like it, but, it's actually built very well, however, since it goes quite a way into the neck, it ends up being quite long.
Keep in mind the trailer is all either 75x75x4.0 or 100x50x4.0 RHS, so it has a fair bit of steel in it.

I am going to buy an adjustable gforce nozzle by taskforcetips when I get it finished and was looking at a foam attachment, but, didn't know if it was worth it... you guys think so?


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## 2dogs (Nov 11, 2014)

TFT is expensive stuff. I would go with a standard (for 'Murica) FSS fog nozzle. Here you can pick up a used one for under fifty bucks.


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## 066blaster (Nov 12, 2014)

Looks nice. The topic reminds me of a video I seen where a large wheat field was on fire. The farmer hooked up a large chisel plow and made a pass in front of the flames and the fire went out when it got to the plowed area. I see you have a big tractor there. Keep that idea in mind if your water fails.


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## STOIE (Nov 12, 2014)

Don't worry, I have that covered!

I'm working on getting a dozer at some point in hopefully the not too distant future, I have a fair bit of work to do and the costs for a contractor will half pay off my initial investment in a D6. (I know I am completely missing the learning curve point, but hey, you won't learn if you don't try... and I love new toys!!!)


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## bryanr2 (Nov 12, 2014)

Stoie,
See your from Snowy Mountains.... is that where "The Man from Snowy River" and "Return to Snowy River" were filmed? They are 2 of my favorite movies.


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## STOIE (Nov 12, 2014)

That's the place!


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## STOIE (Dec 2, 2014)

Here are some updates, I built a frame for the floor at the front of the trailer and a grab rail, so you can be standing up there while someone drives you around watering down.
I filled the tanks with 1000L and drove the trailer around and it works great.

Last things to do are:
* Fit the last remaining camlock to the hose for the filler (near the hose reel)... was short a few hose clamps :S
* Bolt the toolbox to the front (just in front of the front tank) on the floor.
* Make a mount and put on a removable boat fuel tank.

That should be about it!


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## STOIE (Dec 2, 2014)

More pics with the water.


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## bfdast (Dec 7, 2014)

Only problem I see is the plumbing. You have the feed line to the pump coming from the top and is not rigid. That will he a problem!! The line going to the pump should be at the bottom an the fill line at the top. Also need to vent it. The line feeding the pump has to be piped with steel pipe. Will cause the line to collapse. Also what size hose are you using for an attack line? What size GPM\PSI pump is it? That will contribute to what type of nozzle you need. Different nozzles require different psi to be affective. If you need anything let me know. Been a career firefighter in a large city for little over 10yrs so can help with anything you need.


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## STOIE (Dec 7, 2014)

bfdast - very much appreciate the offer to help!
To answer some of your questions:

Feed line is on the bottom of the tanks, 2" ID... the fill is the 2" ID on top... so the other way around to what you were thinking... I have the ball valve at the back (drain side) so that I can shut it off and keep the tank outlets open, so... when filling both tanks can equalize.
Breather when draining the tanks is the filler hose and when filling, I just loosen the caps on top the tanks. (could do this for either operation)
The hoses you see on the outlets are actual suction hose, they are very thick walled 6-7mm and are spiral bound, as to not let them collapse on themselves.
I understand that anything will collapse given too higher flow for said restriction, however, I am certain the hose with everything 2" is fine for my requirements.
I can get to around 150LPM before I start exceeding 1.2m/s (or 4fps) on the suction...

As for a nozzle I am looking at an adjustable (g-force) in a 500KPA model, the pump can push around 350LPM @ 500KPA, which means satisfy 3 of the 5 flow rates for the nozzle.
Flow of the gforce would be 100LPM at lowest setting, then 200/300/400/500, I plan on only using 100LPM and occasionally 200, but time will tell. (this would be run off a 38mm hose, from the third discharge on the pump [highest pressure])

I guess one option I have if I end up having too much velocity on the suction is to run the front tank into a 2">3" expansion adapter, then 3" back from the rear tank... that would double my cross-section and thus mean I can run up to 300LPM before exceeding 4fps on the suction. (useless going any bigger than that, since the tanks only have a 2" outlet)


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## M.R. (Dec 7, 2014)

The boat trailer design, where the tongue
Is coming straight off of the frame will
be where one will see metal fatigue at the
Point where it's attached. Thinking 'gussets'
here if you didn't want to cut it loose .....
would be better to go under the main frame tying
into a few of the Cross members. Adding material
to it or shorting the tongue length, also reducing
the drop required at the coupler.
The surge forces traveling with less than full
Loads.....Might save one some hindsite. ;-)
.
'Wetter Water' can also be added to the tanks. 
http://www.goecoline.com/auto-industrial-maintenance/fire-fighting-products-1/water-wetter.html


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## Sagetown (Dec 7, 2014)

Good Looking setup Stoie.


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## M.R. (Dec 7, 2014)

It is nice clean work, one can take pride in!


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## STOIE (Dec 8, 2014)

Yeah there are some pretty substantial gussets inside the frame, where the A-frame meets the main side rails.
I do agree that's where the point of weakness is, the drop frame that then connects back from underneath provides more strength as it's triangular... but, still.
I was thinking originally (and my still do it) of welding a bar back up from the back of the dropped *hoop* to the supports under the tanks I put in... this would greatly improve the rigidity there.
As for the drop neck, it's actually very strong, however, the bolt that holds it on is loose.. this is really annoying me at the moment, so I think I am just going to weld the tongue in permanently... which means I can also then weld a brace behind it, which again would greatly improve strength in that area.


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## bfdast (Dec 9, 2014)

Ok make sure your nozzle does not exceed your pump, you will be pissng in the wind. What happens in any type of firefighting situation is your actually apply in water above the fie to disrupt the fire, what happens is on major fire when you apply water directly to the seat of the fire it will evaporate before it gets there. You have to go slightly above the fire causing the water to disrupt the fire in taking away the oxygen from the source. No oxygen, the fire can not continue to burn causing effective extinguishment. This applies manly to structures but has an effect on brush as well. If your pump can not supply the correct psi and GPM your fire stream will not be effective. Most structure firefighting nozzles goes like this, smooth bore nozzle= 50 - 75 psi, fog nozzles require 100 psi to be effective. Now read the nozzle specs and follow it. Next problem (school in it self) is friction loss. This is a engineers favorite subject Lol. Believe me it is a LONG class to teach due to complexity. Basically water losses pressure due to going up hill (fun to calculate on high rises) and gains going down hill. Each diameter of hose has its own friction loss. 
Basically there is alot of science that goes into firefghting and needs to be understood to be effective. If you are building to use for brush and woods you can get buy with a basic set up. If you are wanting something to protect your exposures (house, barn, etc.) You have to consider all of this to use the amount of water you have effectively and not run out or waste it. This is why as a firefighter you start out in rookie school which is 18 weeks, drivers school is 8 weeks, capts don't have school but here must have minimum amount of experience and go through alot of classes. All this is to understand the science and do our job correct and allow use to hopefully go home at the end of our shift


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