Water tank size on WL Engines

Water Tank Size on Wildland Engines?

In the CA Governors budget is $5M to study new technologies for wildland fire control, has anyone thought about adding water to our wildland engines? 500 gallons has become the de-facto size, but why? With the popularity of POLY tanks by the late eighties, usually made by sub-contractors, standard size for design and engineering was advantageous and 500 gallons seems to work. Lower cost, slightly lower weight and elimination of corrosion problems makes them very popular, but there is a downside, SIZE! The material is between ½” to ¾” thick as compared to ¼” to 3/16” for steel tanks. The biggest size issue for poly tanks is the spacing around them that is required so they don’t rub against and body component. A clear space of 2 inches minimum sides and top plus the top requires a support structure for the hose bed above. Steel tanks can be part of the body eliminating the gap area, type 3’s were built this way for decades and tank sizes varied. The downside to unibody build is initial and repair cost. The cubic space savings of a 500 gallon steel unibody build over a poly build ranges from 20 to 30,000 cubic inches or 12 to about 17 cubic feet. That comes out to 90 to 125 gallons. Because of emission requirements engines have grown at an alarming rate in the last 25 years, so I would not advocate bigger just better use of space. Most of the large type 3 chassis can handle the additional 900 to 1,250 pounds or can be up-specked a bit to handle. The added cost per unit is significant, but apparatus cost is literally pennies compared to the cost of staffing them over their life. With the larger more intense fire and the intermix structure firefighting type 3’s do these days seems like a 20% increase in water would be helpful. I worked on engine specifications for my agency for nearly 20 years and spent a very short time in the industry, now retired and not involved in the apparatus industry just curious what others think.

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Ill take an extra 500 gallons per strike team.

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didn’t think of that

The CDF model 11 was a great concept bringing 1200 gallons with it. With the current 34 though, I would hope the engine would get smaller and never larger.

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Yes they were, but chassis at max, but still smaller than the 34’s. I think the 34 is beyond big, but as I mentioned with different construction type there is the room without increasing footprint. If you go with an inverted “T” tank like the old 5’s and 1’s you can also get the center of gravity way down. Newer materials remove the corrosion issues, but still cost a bit more.

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Don’t claim to be an expert but here are my 2 cents. Yrs ago they had 1’s & 5’s with 500 gal. Low total height and could go about anywhere. Type 6’s were almost NEVER ordered cuz the 1’s & 5’s could get up and down the roads wherever needed. Then came the model 9. 650 gal with a non-rated 650 GPM pump. Taller, longer and much underpowered. Then came the 4x4 model 34’s. So tall they cant go where the old Model 5’s or 14/15’s could go. Might as well have a short wheelbase type 1 try to get into the remote cabins and narrow by-ways. NOW, we order type 6’s. They were unheard of in the 70’s thur early 2000’s. It’s not just water delivery. If you can’t get there with a 2000 gal, 8 wheeled Oshkosh it kinda useless. Total weight is also a consideration due to small bridges. A fighter Bomber doesn’t make a very good Bomber. And it make a very poor Fighter. We keep trying to put 10 lbs of crap in a 5 pound bag or, A jack of all trades and master of none. We used to dispatch Task forces. A mixture of types that allowed us to use what we needed when we needed it. 1 type 2, 1 WT, 2 type 3’s and a type 6. Fully self sufficient and flexible. It seems we have dumbed down the system and only order strike teams today until everything is so drawn down they have no choice. Even on a 5 player basketball team you have 2 guards, a center and 2 forwards. 5 of any 1 type would be a disaster on any court. I think we need to be more flexible. Water carrying capabilities are not the total solution to improving the abilities of extinguishing fire.

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Great points by all. I’ve been fortunate to work on model 1/5’s, 34’s, 9/11’s, an assortment type 1 & 3’s, but my favorite is definitely the 14 & 15’s. If they could put a total 650 gallons on a 14 or 15, I think access & functionality would be amazing.

I remember during the water scarce years we carried wet water on the engines to stretch out that 500 gals of water. it was very effective. but it wasn’t cheap.

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In San Diego unit we would always add a model 11 to a strike team when possible.

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Or model 8 for us oldtimers.

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U talk about under powered and over heating. But you could mobile attack for days if the ground was right.

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Model 11 was my favorite, especially nice in WUI situations. 1200 gallons, 500 gpm midship pump and two FF was a perfect attack setup. :+1:t4:

We also had 2000’ 1.5” in hose-packs and had 850’ 2.5” for working from hydrants. Add three 100’ preconnected 1.5” & two 150’ hardlines.


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Good to see this interest in apparatus, it seems the folks in the field don’t get much say in what they are given. I fully agree that type 3’s are to big but the chassis height and size are not changeable, type 6’s are back to limited GVW and loading to near 100%. As situation vary the needs vary as well and only one tool has some severe limitations but on the flip side you get some big efficiencies by using one model, look at the success of South West Airlines, all 737’s. My original point is that with different slightly more expensive build type we can add more water without increasing size, or the other option is decrease size and maintain 500 gallons. If you see Marin County Type 3’s (a number of others us similar speck) you can see the body build is slightly lower, tank is much lower, 4" narrower, I don’t recall how much shorter in WB and Length but slightly more compartment and hose bed cubic footage compared to the 34’s. This was accomplished using an internal steel inverted wet side “T” tank. Not a new idea, just modification of an old idea that worked well for decades.

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Here’s this dead horse again, Model 34s are not too big. Quick cursory look at the Marin specs would indicate to me that those engines would not meet the mission of CalFire. I’m not saying those specs are inferior in any way. They were just designed for a different mission.

Btw, the line drawings I have show the Marin engine 1" taller, same width, and 8" shorter wheelbase. Not sure how they have more compartment space. Not sure what is/was deleted to accomplish this. I like the idea of an inverted tank to lower the COG, just do not know the ramifications of using them.

That being said, I never had an issue with my Model 34. But I was trained pretty well on them, in addition to in service practice.

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Sir we called the primary pumps on the #1s and #5s a Midship pump and the Buildup mounted pumps on the other models a Skid mount

The only performance difference is no ox pump, pump and roll is done with a PTO and special relief valve. The space comes from internal unibody tank, see previous posts regarding space savings over poly tank build
.

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