trojan 40' fly -year 1980 - some questions

federico · Post by **federico** » Sun Aug 15, 2010 6:20 pm

Hi, just registered in your forum.
I've tried to find something in the web and in your forum fr my topics, but no results, unluckly.
I've the possibility to buy a 40' fly age 1980 equipped with 2 x 275 hp GM diesel engines. Since I need to find a compromise betwen speed and fuel consumption (here we pay about 6 USD per 1 US gallon of diesel fuel!), I would know, if anyone of you have a real direct experience, the fuel consumption of this boat at the cruise speed (which is ?) and at full throttle (which is the max speed ?).
For what I know, the engines should be GM 6-71 or 6V-71 turbocharged.
The fuel tank is declared about 400 US gallons.
Which is the displacement of the boat ? At first impression it seems built with thick hull without economy and so quite heavy (at least for the european standards where a 40' fly weights about 9 or 10 metric tons).
Always about the hull, any experience of osmosis problems after a certain period ?
really many thanks and regards to everybody
Federico

prowlersfish · Post by **prowlersfish** » Sun Aug 15, 2010 9:10 pm

I am thinking this is a F40 aft cabin in that case the top end would be around 17 knots w/clean bottom

federico · Post by **federico** » Mon Aug 16, 2010 3:46 am

Yes, you're right, 40' aft cabin.
Thanks for the top speed. So I could presume a cruise speed of about 12 kn.
Have you no ideas where to gather the other infos ?
thank you

k9th · Post by **k9th** » Mon Aug 16, 2010 5:35 am

Welcome to the forum Federico

prowlersfish · Post by **prowlersfish** » Mon Aug 16, 2010 8:34 am

I know one former owner of one if I run into him I will ask some questions . below 8 knots it will sip fuel

federico · Post by **federico** » Mon Aug 16, 2010 4:19 pm

Thank Tim for your welcome and thank Paul for support, I look forward to know what you can discover. By the way, no literature on this issue anywhere (user's manual, power/consumption curves,...) ?
Federico

LSP · Post by **LSP** » Mon Aug 16, 2010 8:26 pm

Welcome to the forum Federico

federico · Post by **federico** » Tue Aug 17, 2010 9:20 am

thank you Will

prowlersfish · Post by **prowlersfish** » Tue Aug 17, 2010 12:16 pm

Maybe Bob (becon marine ) or John Leeds at marine tech will have that info .

federico · Post by **federico** » Wed Aug 18, 2010 2:46 am

I'll try to contact them.Thanks.

bthomas70 · Post by **bthomas70** » Wed Aug 18, 2010 9:42 pm

Federico,
I have a boat test article from a November 1978 Motor Boating and Sailing magazine that shows a top end speed of 17.5 knots while burning 31.2 gph. The F-40 had what Trojan called a "Dual Mode" hull and could travel at trawler speeds or planing speeds. In displacement mode it burned just 4.3 gph at 7.3 knots. It looks like best cruise speed is about 1600 rpm, 8.6 knots while burning 9.8 gph. The article notes that their test boat was hull #1 and is up to 3,000 pounds heavier than future boats and may have been propped wrong. Trojan expected to get 4 mph better speed across the rpm range. The test boat had GM 6-71N's and weighed an estimated 27,000 pounds. It holds 445 gallons of fuel. Can anybody tell me if there is a way to post a pdf file to the forum? I'd be happy to post the article or send an e-mail to anybody who is interested.
Brent

federico · Post by **federico** » Thu Aug 19, 2010 2:31 am

Brent, really many thanks!! Great job.
You solved all my questions in only one shot.
Yes, it will be interesting see the article: my email is fpuccetti@gmail.com
Does the indicated burning rate refer to both the engines as total, doesn't it (hopefully...) ?
Again thank you.

prowlersfish · Post by **prowlersfish** » Thu Aug 19, 2010 6:39 am

Trojan calmed 18 knots but 17 is the true number in the real world

prowlersfish · Post by **prowlersfish** » Sun Aug 22, 2010 6:46 pm

I just talked to the former owner of one and the top speed was just under 17 knots ,and this was with 310hp 671 DD

pfeifferj1 · Post by **pfeifferj1** » Tue Aug 24, 2010 3:54 pm

I have a 1983 40 aft cabin. with a clean bottom and running gear at wide open throttle I have briefly seen 17K. Mine has J&T Detroit 6-71Ns rated at 310hp and I normally cruise at a power setting of 1850 - 1900 rpm. That gives me a cruise of 8-10kts depending on conditions. The fuel burn figure that I use for planning is 10-12GPH again depending on conditions and use of the Gen set. On a long trip I can set it up at 16-1700rpm and get 8kts and 8GPH. Fuel load on the boat is 445Gal. 160Gal on each side tank and 125Gal in the Aft. The Water tank is also 125Gal. All this being said: When I am just curising around locally I run with 1/2 fuel 1/2 water and average 8-10 knots and 8-10 gallon per hour. It's and outstanding strong well founded boat. good luck
Han