Trojan Boat Forum

jordan wrote:I would figure more like a gallon per mile with twin 318's and not at 18 knots. My F- 32 with 318's, I plan on 1 gallon per mile at 7-8 knots, 1600 rpm and not planning or 1 gallon at 12- 13 knots at 2300 rpm at a slow plane. Any thing more than that it is all down hill so to speak.Jim

An original Trojan spec sheet that I got some information from for the F32 with twin 318's suggests that the fuel consumption once on plane remains fairly flat till the 4 barrels switch in above 3000 rpm.
What I get with mine seems to confirm this... though it is by best guess calculation as I do not have fuel flow meters which I don't consider worth the expense as the Trojan's fuel burn is so flat once on plane till the 4 barrels hit.

Trojan calls 2500 rpm slow cruise and 3000 rpm max cruise and 4000rpm max: speed in that data sheet. Here is the information I saw:
RPM.............MPH.........calc Knots........GPH................calculated mpg
2500............15.0..........13.04.............15.6.................0.96
3000............21.3..........18.50.............22.5.................0.95
4000............32.3..........28.07.............40.5.................0.80

Based on the above data I made the decision to tend towards the max: cruise level so try to maintain 3000rpm most of the time. Have you evaluated what your boat does up nearer 3000rpm?
I tested and concluded that the extra speed of max: cruise was worth the 1% mpg penalty as my run time was reduced nearer 30%.

Looking at your numbers I have one other question... the 7-8 knot speed at 1600 rpm can you get the same speed with lower revs?
I seem to get that speed with lower revs... no trim tab. I find that the rpm range is quite large for little speed increase at that low displacement running speed.... so am suggesting maybe you can throttle back, push less water and still maintain the speed. I do carry a dinghy on the swim platform and that could be a key difference at non plane speeds.

That is a great looking 30! The cockpit area is huge and you'll have a lot of fun with that much space. I've considered the F-32 many times and just let a beautiful one go - main reason is the cockpit area of the F-26. Just like yours, it's big and we spend a lot of time outside the cabin with grandkids, etc.

The deck may be soft in spots. Most likely places will be any place were there is hardware mounted. For some reason either Trojan or the marinas who installed some of the hardware did not use any caulking under the screws/bolts. Over time water infiltration gets into the balsa core and that starts the rot. Many, many threads on this forum about this - repairing from the top, and the cabin.

I always measure fuel consumption in gal/hour versus statute miles, etc. This, to my humble mind, is the only way to measure fuel consumption on a boat. That being said, the single Chrysler 318 on our boat (1977) ran at 3 gph over a 500 mile trip along the Erie Canal last year. Average speed for the trip was 8 mph (no reason to hurry in the Canal and the speed limit off the rivers is 10 mph). The engine was tuned last year, new plugs, wires, etc. The boat was LOADED with gear and 2 adults. My fuel consumption has run from 1 to 10 gph dependng on speed, conditions, etc. That's with a single engine.

One more piece of advice......life's short. If you like the boat, buy the boat. The stuff you'll learm from it is not written in any books.

randyp wrote:I always measure fuel consumption in gal/hour versus statute miles, etc. This, to my humble mind, is the only way to measure fuel consumption on a boat.

I agree and that is the first thing one gets when taking measurements anyway.... consumption and time.
<aside>
Now the derived figure of mpg or gpm can be worth knowing as it allows one to get a cost/fuel need for a trip quickly with one less step in the calculation as distance to go is usually known before speed is considered to get the time.
Also mpg rather than gph may have more meaning to the average person.... up here in Canada we use litres/100 Km as the standard for car fuel consumption.
That figure gives me no real feel of what is really going on so I convert them to mpg. Is that because I was pre metric as a kid when I looked closely at mpg... of course my mpg was British gallon not US so another confusing factor to skew the thinking.
My boat fuel data is logged in litres/hr because we buy fuel in litres.

Dan you Must run your boats just right . I never got close to that with my F30 . and your doing great with your F32

I like gal per hour as if you keep track of that you know when somethings wrong . where as if you use mpg that can change do to tides . if you fighting 4 knot tide your lossing 4 knots over ground ( asuming you run the same rpm ) I do track mpg but use GPH
for keeping track . its still depressing when you know how much you burn .

i know that when my gas gauge says empty i need more fuel