Fuel Consumption....everyone please weigh in....

1: What type of Roamer do you own? (Size / model / Steel or Alu / estimated Displacement in # of lbs)?

48 feet/Roamer Rivera/Alu/26,500 lbs

2: What is your power setup?

3208 Caterpillar Diesels

3: What (if any) modifications have you made to your engines that would affect fuel economy (electronic ignition, electronic distributor, high-efficiency coils, wires, etc. etc.)?

None since I bought it, the PO replaced the gas engines with the 3208 diesels.

4: What is your prop size and pitch?

25"/26 pitch

5: What is your normal cruise speed?

7 knots

6: What is your normal/average fuel consumption across the varying speed ranges (or any ranges that you know), estimates are fine, and either GPH or MPG is fine.

10 GPH

7: If you have changed or tweaked any of the above variables since owning the boat, please describe what you changes you made, and any effect it had on fuel economy. If I failed to mention some change or improvement that you made, please describe it along with what change (if any) it had on fuel consumption.

8: What is your GPH burn for your genset (if present)?

2 GPH

Request a little added info.

Bally, I'm very interested in your figures. I am re-constructing a 58 alum and have not selected engines yet, but I'm going to power it only to displacement speed. My hull speed will be a little over 9 knots. Calculations say I only need a total of 200HP but will probably install t/170HP - 200HP.

What are your 3208's rated at ( ? HP @ ? RPM) and what RPM do you run to maintain the 7 knots? What reduction gear do you have?

Thanks
Art

Well, Hello Fellow 38' Regal owner!
Ours is a '69 38' regal, the first one off of the line.
It was repowered in 87 with two big block Ford 460's, which I wouldn't trade for the world.
We get about a mile a gallon, and the gen usually will burn a gallon an hour.
i've cheated on the gen lately though - we spend nearly every weekend on an island with the boat and have to create our own juice. I finally bought a Honda 2000i gen which is plenty to run the fridge, fans, microwave, oven, water heater (one big appliance at a time, of course.) At 10-12 hours per gallon, we've about paid that thing off with the difference in fuel consumption in one summer!

I would not down size your engines. Ours are pretty special boats - having a putting 38' wouldn't be good in my opinion. I love it when owners of newer clorox bottle boats our size come cruising up - I can leave them in my wake and it's good!

As a wise friend of mine said:
"Gas is (still) the cheapest thing you'll put in a boat."

427's and fuel economy

I used my 35' with 427's for a towboat on Lake Erie for many years. When you are out there in the slop and you can set your coffee cup on the helm the fuel economy doesnt really matter. These boats are awsome if you are in any way exposed to possible rough water such as on a long trip or out fishing a lot. Best thing you can do for performance or fuel economy is do a compression test and make sure you are up to snuff. Then throw out the points and put conversion kits in the distributors. Remove the resistors and go to a regular coil, 8mm plug wires and Bosch Platinum plugs. My 35 with lots of gear was running 24 knots and purring.

new Diesels and how big is enough?

Chriswufgator

WHEW _ This took time to digest. Chris, you really put some time and thought into that response. I have to begin by saying I agree with some of what you say. And my disagreements stem from your not being familiar with my project. I visit this Roamer site regularly to get aluminum info. And having spent, well let’s just say ‘a long time’, on the water, I enjoy listening to the Q&A on the site. Technically my boat was (is) a Roamer 58. We am building a boat to retire aboard, and plan to travel extensively, conceivable 1,000 -2,000 engine hours a year. This makes both fuel consumption and mechanical maintenance a significant issue.

Let’s start with where we agree. The theory that it requires a given HP to produce a given speed – we agree. Up to the 'Hull Speed' that figure is somewhere between 2 and 5 HP/ ton. The variable being the efficiency of the hull design; narrow vs. wide is more relevant than round vs. hard chine. So whether you deliver that HP using 700 HP @ 21% or 200 HP at 80% makes no difference to the boat. And I agree with you that the Roamer hull is not particularly efficient, based on my 17-foot beam. We are in agreement.
Above that ‘hull speed’, consumption rises exponentially until you get ‘on plane’, but it never comes back down to displacement consumption rates. I have personal issues about whether the 58 foot Roamers ever really ‘planed’ with the 320HP DD’s. * alloyd2sea – chime in here –please. But this is beyond the scope of our discussion.

I also agree whole-heartedly that diesel engines with the new common rail fuel systems are much improved. The fuel consumption curve is better through the entire RPM range. But that 'curve' did not disappear. They are still less efficient at low RPM, and their maintenance through the life of the engine increases if they are used this way. Everything I have read (I’m not a diesel mechanic or engineer) says “Don’t run a diesel for long periods below 75-80% of its power rating”.

I also agree that at resale time, potential buyers looking for a Roamer will not want an anemic pussy-cat. So we have to ask: “When is a Roamer no longer a Roamer”? Your advice was based on a presumption that my 58 is still as it was pictured in the brochures. It is not. I found this boat, about 15 years after it had suffered a salon fire, which destroyed the roof. The interim owners fabricated a plywood menagerie that would have banished them from the Roamer Club. Since we purchased the boat, we removed everything; let me repeat EVERYTHING, down to an aluminum hull. I mean I could take 80 of my closest friends out fishing, BRING YOUR OWN OAR! A 58-foot open row boat. Now you see where I'm at? – this boat will never be a “Roamer” again.

I’d like to continue this discussion, but am short on time.

I uploaded a pic for this location but lost it in cyberspace. Sorry

NOTE TO MGMNT _ Please do not banish me from the site. I still like Roamers and respect the ones that are intact.

Art not Science

1: 37'/Riviera/Tin/19K+ lbs; less if cant afford to fill gas tanks.

2: T/454s w/Borg Warner 1.52:1 Velvet Drives

3: Electronic ignition.

4: 17x18s ('cause of the 1.52:1 reduction)

5: Hull speed (8knots) punctuated by short bursts of Sea Ray-passing speeds of 25+, depending on the insolence & temerity of aforementioned ne'er-do-wells.

6: We burn every drop, no matter how fast we go. Occasionally, the wind helps out; but usually doesnt. Figure 25 gph at cruise (3000 rpms).

7: Canned the 327s in lieu of hi-po 454s (http://www.geocities.com/tin_tonic/MotorCity.html). Subsequently added alcohol-sensitive, wind speed thermometer - gets hot every time the local contingent of Sea Ray blows up: seems to improve throttle action - everytime!

8: Two squirrels consume approx. 7 nuts per minute - depending upon axis angle and geothermic spin rates.

Hope this is helpful...

If everyone could answer the following questions, it would benefit us all by establishing a set of numbers that we can each compare to our own.

1: What type of Roamer do you own? (Size / model / Steel or Alu / estimated Displacement in # of lbs)?

1968 46’ Roamer Riviera/ Aluminum hull / wfuel tanks full appox. 40,000 lbs
(crew of four, provisions, 7.5 outboard, 12 ft dinghy…)

2: What is your power setup?

Twin 8V 71N Detroit Diesels

3: What (if any) modifications have you made to your engines that would affect fuel economy (electronic ignition, electronic distributor, high-efficiency coils, wires, etc. etc.)?

No modifications

4: What is your prop size and pitch?

Props are four blade 28"X28"

5: What is your normal cruise speed?

10.5 to 12.5 mph SOG

6: What is your normal/average fuel consumption across the varying speed ranges (or any ranges that you know), estimates are fine, and either GPH or MPG is fine.

Last 220 miles, from fill up to fill up was 190 miles upriver from Belpre, Ohio to Marina slip in Pittsburgh at 1500-1600 rpm plus one 30 mile turn around the pool at rpm from 750(no wake) to 2100(2 mile run downriver), in addition to time spent in 7 locks at idle speeds with hardly any time spent waiting for lock up, used 268.8 gallons of diesel for an average fuel efficiency of 81% of a mile per gallon.

7:If you have changed or tweaked any of the above variables since owning the boat, please describe what changes you made, and any effect it had on fuel economy. If I failed to mention some change or improvement that you made, please describe it along with what change (if any) it had on fuel consumption.

Only the oil was changed to protect the innocent…

8. What is your GPH burn for your genset (if present)?

Accurate data on GPH for 7.5 Kohler not available due to lack of time logs, however, on one run of 72.6 miles upriver including two locks with little wait time the starboard tank drew 6 more gallons than the port tank (Kohler draws from stbd tank.) If one can assume an average SOG of 10.5 mph with one hour of aggregate lock time then the segment seems to have taken 8 hours plus or minus and that would average out to three quarters GPH for the Kohler without studying differences in fuel usage for the big Detroits. Since the Kohler went south for the last five days of our 26 daylong jaunt and the difference at the last fill up was 132 port and 136 starboard, a 3% disparity hardly seems worth mentioning.

regal data

1: What type of Roamer do you own? (Size / model / Steel or Alu / estimated Displacement in # of lbs)? Regal 41 alu about 25,000

2: What is your power setup? Twin Cat 3126 430 HP tied to Twin Disc 507A1

3: What (if any) modifications have you made to your engines that would affect fuel economy (electronic ignition, electronic distributor, high-efficiency coils, wires, etc. etc.)? Sold them! used to get .6-.7 mpg at 3050rpm at 17mph with 427's when they ran

4: What is your prop size and pitch? 23x25 cupped 3 blade tranny ratio 1.51/1

5: What is your normal cruise speed? old 17 new 24-26 at 2100rpm

6: What is your normal/average fuel consumption across the varying speed ranges (or any ranges that you know), estimates are fine, and either GPH or MPG is fine. first 1000miles is about 1.1mpg

7: If you have changed or tweaked any of the above variables since owning the boat, please describe what you changes you made, and any effect it had on fuel economy. If I failed to mention some change or improvement that you made, please describe it along with what change (if any) it had on fuel consumption.

8: What is your GPH burn for your genset (if present)? Never figured it out it is a yanmar diesel and after a week trip where it runs about 40 hours i find the tank it draws on is down what i think to be about 10-15 gallons. How accurate this is I don't know. but in my scheme it is insignificant as no matter the fuel cost there will be ice for the captains after cruise cocktail.

Hope this helps.
mark

1. 1965 33' steel Riveria approx 14,000 lbs
2. Original (1has been ovhld) 210 hp 327's, 1.5:1 Paragon reduction
3.Have put on MSD electronic ignition, drastically improved reliability but did not notice performance or fuel consumption improvements
4. Don't off hand remember prop size
5 and 6 16 mph at .8 mpg (stat) or sailbote speed 7 mph at about 1.5 mpg
7. Tweaks none other than the MSD and being easy on the throttle. Clean scum off the bottom & reduce weight of junk in the boat.
8. Have a 2 cylinder Onan about 4 kw, does not burn enough to worry about.

I couldn't resist ressurecting this thread as I'd like to see a few more data points and I've been away from the forum for a while.

I've got a 74 55' aluminum Riveria, about 54,000 lbs from the factory and probably heavier at this point.

Power is a pair of 8V71TI's at 390HP. Propellers are Michigan Wheel 30 x 26 Equiquads.

I cruise at about 13 knots, I've only kept track of the fuel consumption once, that was on the maiden voyage from Portland, OR to San Francisco in 2005. It was the first time that boat had been run in about 9 years and it's performance was awsome (there wasn't a mosquito left alive on the West Coast).

All joking aside, we averaged .75 nautical miles to the gallon...

Jim Bauer
San Ramon, CA

Hello,I am new to this website, please forgive any mistakes to my etiquette.

We have a 1962 Roamer Riviera, hull number 4 of 14.  We have done a lot of work on her over the last five years and am very interested in your fuel efficiency conversation.
1: What type of Roamer do you own? (Size / model / Steel or Alu / estimated Displacement in # of lbs)?

1962 44' Riviera / Steel / 42,000 # wet, per the yard lift operator. Heavier due to full pilot house.

2: What is your power setup?

Twin, 1968 Ford 427s, Chris Craft +/- 150 Hrs each SMOH

3: What (if any) modifications have you made to your engines that would affect fuel economy (electronic ignition, electronic distributor, high-efficiency coils, wires, etc. etc.)?

Electronic distributors, New Edelbrock Carbs, New Holly Red electronic fuel pumps,

4: What is your prop size and pitch?

24 x 22

5: What is your normal cruise speed?

Upstream 8-9 MPH, dependant on current, at 1800 - 2000 RPM
Downstream 10 - 11 MPH at 1750 - 1800 RPM

6: What is your normal/average fuel consumption across the varying speed ranges (or any ranges that you know), estimates are fine, and either GPH or MPG is fine.

On a trip last year to Quincy, ILL and back, about 265 miles, we averaged (1) MPG round trip.

7: If you have changed or tweaked any of the above variables since owning the boat, please describe what you changes you made, and any effect it had on fuel economy.

No yet, but we are very interested in your findings

8: What is your GPH burn for your genset (if present)?
We seldon use it but it seems to be about 1-1.25 GPH (Original Kohler 5 KW)

Diesel's Have to run 75-80%...Bunk

I am sorry I have to disagree. Yea, that was the talk for years past, although I have one of the best Mech. in the country, Master mech for Johnson and Towers. Not a standard Mariene Mech. That went to night school for his diesel shingle. No offence to thoes who did, I personally don't even have that. The old school of thought was that if you did not run the diesel engine at 75-80% that you would have a carbon load up and the end result would be needing to run to the peggs to clean it off. They believed it would burn up the pistons and the injectors as well as waste fuel Both are incorrect. I have 3208's which are probably the most innefficent diesel due to the short stroke. Carbon build up or ineffeient fuel burn is due to the heat of the engine and the ability to vaporise the fuel. The more interesting conversation would be if your are running at lower RPM do you the temp of your Thermostat? I also once had a Go FAst captian tell me that I needed to run the 454 at a minimum 3800rpms. The same dumb logic. Don't be fooled. Run the boat at wat you are comfortable with and save the fuel. I have been in these 3208's for 4 years and generally cruise at 1900rpms and they run great and I have them looked at yearly. I do change the filters regularly and the oil, as well as cleaning the air filter. And acid wash the heat exchange.

I also have 3208s, mine are rated at 210 horsepower each (naturals), and run at about 1900 RPMs with no problems. I like the engines and have owned the boat for over three (3) years with no problems to date with the engines. I know there has been a lot of discussion about under power but she had the 3208s when I bought her and I liked that fact. The PO had done a repower about 1990 and put them in then. I can do about 8 gallons per hour with just the engines and just a little less than 10 gallons per hour with the gen set running.

I do have an exhaust leak in the pipe going through the aft stateroom but that does not reflect on the engines. That will be fixed in a few weeks when I pull her to repaint the bottom, always some thing to do on them and never enough time or money to get it done.