Our Safari Condo (SC) Alto F1743 trailer came with dual 20 lb steel propane tanks. For our style of travel we were carrying around a lot more propane than we actually need. The Truma Combi heater is pretty efficient and we have a 12V refrigerator. Switching to smaller 11 lb composite tanks provides a little more propane than a single steel tank while retaining the operational advantage of two tanks (tank empties, switch to full tank, refill empty at leisure). And it shaves over 35 lbs from the trailer, most of it directly off the tongue. Not coincidentally this is about the weight of a recumbent trike that may or may not wind up in that position.

Other advantages to composite include the ability to see the propane level and arguably greater safety (under stress the tanks will melt and the propane will burn rather than explode). Disadvantages include a regulatory maximum service life of 15 years and fewer businesses that will fill them. We bought the tanks from U-Haul and then discovered they won’t fill them, at least not our local franchise. Composite tanks are fairly rare in the US and apparently some folks won’t accept the imagined liability. Or something. The requalification interval is 5 years, the same as steel.

Configuration	Propane capacity	Empty tank weight	Full weight	Δ from factory (76.4 lb weight)	Δ from factory (20 lb capacity)
Two 20 lb steel tanks (factory)	40.0 lb	34.0 lb 37.6 lb (measured)	74.0 lb 76.4 lb (measured)	0 lb	0 lb
One 20 lb steel tank	20.0 lb	17.0 lb 18.8 lb (measured)	37.0 lb 38.2 lb (measured)	−38.2 lb	-20 lb
Two 11 lb composite tanks	22.0 lb	17.2 lb 18.2 lb (measured)	39.2 lb 39.6 lb (measured)	−36.8 lb	-18 lb
Two 17 lb composite tanks	33.6 lb	20.4 lb	54.0 lb	−22.4 lb	-6.4 lb
One 20 lb composite tank (16.8 lb actual)	16.8 lb	10.2 lb	27.0 lb	−49.4 lb	-23.2 lb
One 22 lb composite tank	22.0 lb	12.0 lb	34.0 lb	−42.4 lb	– 18 lb

I wasn’t confident I would be able to procure these 11 lb composite tanks. In the year or so since I started looking at them, the manufacturer, Viking, was sold to Ragasco. Some research led me to believe that Ragasco might be phasing out the 11 lb variant which seemed to match my observation that sources were drying up and prices rising. So I was happy to find that U-Haul still listed them on their website for a reasonable price of $340 for the pair. However the order immediately switched to backorder. Nearly a month later I received the two tanks at home.

Contrary to some online reports, the tanks were of fairly recent vintage (September 2025) so we’ll get most of the 15 years of life out of them. Each weighed about 9.1 lbs empty and 19.8 lb full. Annoyingly, our local U-Haul franchise wouldn’t fill them even though we purchased them from U-Haul. Zamzow’s Lawn and Garden filled them without hesitation. I think most places will fill them, I’m not too concerned.

The dimensions are different than the steel tanks: slightly shorter and wider. The steel tanks have a steel ring at the bottom that fit inside a roughly 8 1/4″ hole in a flat piece of trailer wall material SC uses for the base. The composite tanks instead have a recess in the base of about the same diameter, and the base is wider. So the composite tanks sit on top of the SC base rather than the bottom, where the ring of the steel tanks hit.

To position / retain the composite tanks horizontally I used some HDPE cutting board material to build up the base and provide a ring that fits inside the tank recess. Actual cutting boards were cheaper on Amazon than the equivalent raw HDPE material. The base piece of HDPE is 1/2″ thick, 8 1/4″ diameter and the ring HDPE is 3/4″ thick with 8 1/4″ outer and 7 1/2″ inner diameter. The ring hits the upper aluminum portion of the base squarely and the fits inside the recess of the tank, preventing the tank from sliding too far side to side (there is a little bit of slop). I cut the circular base and rings with a jigsaw. I cut some holes in the base HDPE with a hole saw bit to save a little weight. Total additional weight from the HDPE is 1.8 lb.

The handles on the composite tanks are wider than the steel, allowing a shorter hold-down bracket. The original bracket was made of pretty heavy (stainless?) steel which IMO was significantly over-built. I made a new bracket using a scrap piece of 1″ square aluminum, 1/8″ wall thickness. I used an angle grinder to cut away material down to the desired shape and then did lots of filing. The shorter, lighter aluminum bracket weighs .2 lb, shaving 1/2 lb off the original.

Final weight savings with full tanks (measured): 36.8 – 1,8 + .5 = 35.5 lb

When mounted, the height of the composite tanks is only slightly less than the steel, so the fabric cover still fits.

Part	Unit cost	Qty	Total cost
18″ x 12″ x 1″ HDPE cutting board	$25	1	$25
18″ x 12″ x 1/2″ HDPE cutting board	$20	1	$20
11 lb composite tank	$170	2	$340
Aluminum hold-down	$0	1	$0
Total			$385