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Old 22-03-2018, 04:48   #1
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Making Voyages on twin gas engines ?

Retired couple
Boat - 2004 Regal Commodore with new twin 4.3 gas engines
Model 2860
Length around 30 ft,
Has a 3 axle trailer but we leave at a marina
After 3 years of ownership a weekender of this type is designed for the once a month user not the twice a week local fishing & sleeping aboard boater
LIMITED on space and unpractical for our present needs ,
UNTIL SOLD this is what I HAVE plus new engines hopefully trouble free
Considering a trip via water from Cocoa Beach too Keys , staying a few weeks then back up
Really need a different boat for voyages RETIREMENT offer the time
but what boat will be next ? Trawler , Sail ,
Have sailed and considering one and next boat selection will be challenging .

Have wide beam boat permit but driving a 9 thousand lb boat on RT 95 not fun and all sorts of legalities if an accident happens plus once I am destination parking truck & trailer add in theft of trailer always a concern
Trying too make the voyage via water
I generally go around 15 knots. I enjoy being on water and don't have too speed . Beaten up by bigger boats wakes picking up stuff in cabin

THINKING , what if I run 12 knots one engine , hour on each engine too keep hour meters close too each other
One engine at 12 knots or both engines 12 knots ???? will I converse 1/2 the amount of fuel burn if one engine is running .
I run one engine at times slow and not much of difference , but I am not going long distance

Trip too keys via water is around 350 miles each way , when I plane at 3000 rpm I am burning 1 gallon a mile
Any other thoughts on making this voyage , mostly intra coastal ,
Tide in my favor helps,

Anybody interested in a trade a 30 ft Regal Commodore with new engines ?
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Old 22-03-2018, 04:59   #2
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re: Making Voyages on twin gas engines ?

There is one other option. Slow down. I used to run a 32 foot Wellcraft St. Tropez with twin 454 Crusaders in south Florida. At six knots , it got pretty decent gas milege. At 26 knots, it made you want to cry. In the ICW, slow is fun. If you enjoy the journey.
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Old 22-03-2018, 05:08   #3
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re: Making Voyages on twin gas engines ?

I see no reason you couldn't use the boat for that trip.

I would suggest doing some speed tests. I'm betting 12kts is just about the worst speed you could do for fuel economy. It won't get you on plane but you will be pushing massive amount of water as you are way over hull speed. Turning off an engine won't make much difference until you get really slow where the internal engine friction makes up a significant amount of the power consumption.

If you really want efficiency, you are probably slowing down to around 6kts and running on one engine will work but good chance the boat is a pig to control at those speeds.

If fuel consumption is a consideration, towing is the way to go.
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Old 22-03-2018, 05:13   #4
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re: Making Voyages on twin gas engines ?

Fuel burn difference will not be that much whether you use one engine or two, assuming the same speed. On the other hand, if you are idling the engines the whole way, in order to conserve fuel, that's not all that good for the engines.

The way I would approach it would be to run most of the time with both engines at low speed. Then, for a little while each day, run one engine at a time, to give each engine an opportunity to get fully warmed up and cleaned out. Or, if you come to a nice open section, crank it up to a higher speed, and give both engines a good workout at the same time.

Good luck, and have fun!
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Old 22-03-2018, 07:50   #5
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re: Making Voyages on twin gas engines ?

Quote:
Originally Posted by Al B View Post
Trip too keys via water is around 350 miles each way , when I plane at 3000 rpm I am burning 1 gallon a mile
Any other thoughts on making this voyage , mostly intra coastal ,
Tide in my favor helps,
I understand what you're dealing with. There are many people in the same situation and I've in fact seen similar discussions regarding that specific route.

Depending on where you're going in the keys you may have to deal with some special permit requirements on US1 as the rules for oversize/overweight are not the same as the rest of Florida.

In very general terms it is an expensive trip fuel wise for boats like yours whether you trailer the boat or just run the ICW with, as you point out, the complications trailer/tow vehicle parking/storage taking up the cost savings you would have from a road trip.

In large measure it really comes down to which way you would enjoy the trip the most.

You will not achieve meaningful fuel savings by running only one engine while on plane although you might at lower speeds (below hull speed).

Your alternatives for fuel economy are: the lowest speed at which the boat planes well probably 12-15 knots -- and no-wake speed around 5-6 knots.

You will have to decide at what point it makes sense to change your boat rather than incur fuel expenses to do what you want
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Old 22-03-2018, 09:09   #6
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re: Making Voyages on twin gas engines ?

Once you get south of Stuart you will be idling till Dinner Key. Long slow trip, better to hop offshore if you can.
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Old 22-03-2018, 09:29   #7
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re: Making Voyages on twin gas engines ?

Just do it and enjoy it.

You will spend some money on fuel, and you can easily calculate it. To put it in perspective, though, to do it on the boat you have, whatever the fuel costs, will be much cheaper than doing it on a new boat you will spend tens or hundreds of thousands on. Fuel is rarely the main cost of boating, and if it is, it means your doing something right, cost-wise I love diesel engines, but for pleasure boating they don't usually pay for themselves in fuel savings, especially compared to a gas engine boat you already have.

You can work out the best speeds, but usually for this kind of boat, just barely on a plane with the engines throttled back is pretty good. "Supercruise", as it were. That kind of boat is usually almost uncontrollable at displacement speeds, so if I were you, I would just put the hammer down and enjoy the ride. Any day, any mile, on the water, in anything whatsoever that floats, is better than the best day you can have on land, in my opinion.
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Old 22-03-2018, 09:34   #8
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re: Making Voyages on twin gas engines ?

On a wellcraft of similar size, the boat starts to vibrate at 6-8 knots and gets scary the faster you go. If it has 2 engines, it's designed to run with both.

If you are running at 12 knots, the bow will begin to rise as the boat tries to plane. You will be pushing alot of water.

I think you need to slow down well off plane for the fuel consumption becomes manageable.
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Old 22-03-2018, 09:37   #9
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re: Making Voyages on twin gas engines ?

ICW and go slow. You've probably made the trip by truck many time, don't do the same ol' thing again.

Lots of folks bought gas boats because they were cheaper than a diesel version, or so they thought. Now they know a gas engine melts credit cards, ugh. You pay up front or you pay long term and you presently have the long term version.

If you don't want ICW slow I would scrap this trip and concentrate on selling or trading your present vessel and looking for a nice diesel trawler. Slow, comfortable and economical!
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Old 22-03-2018, 10:23   #10
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re: Making Voyages on twin gas engines ?

Quote:
Originally Posted by Jammer View Post
I understand what you're dealing with. There are many people in the same situation and I've in fact seen similar discussions regarding that specific route.

Depending on where you're going in the keys you may have to deal with some special permit requirements on US1 as the rules for oversize/overweight are not the same as the rest of Florida.

In very general terms it is an expensive trip fuel wise for boats like yours whether you trailer the boat or just run the ICW with, as you point out, the complications trailer/tow vehicle parking/storage taking up the cost savings you would have from a road trip.

In large measure it really comes down to which way you would enjoy the trip the most.

You will not achieve meaningful fuel savings by running only one engine while on plane although you might at lower speeds (below hull speed).

Your alternatives for fuel economy are: the lowest speed at which the boat planes well probably 12-15 knots -- and no-wake speed around 5-6 knots.

You will have to decide at what point it makes sense to change your boat rather than incur fuel expenses to do what you want
There's no way this boat stays on plane at 12-15 knots. Express Cruisers are typically too heavy to stay up on plane much below 25 knots. The best way to figure optimal burn rates is to install flow meters. At the end of the day it just is what it is. If you want a more efficient boat get a Downeaster or a trawler. Or you could go with one of these: Great Harbour N37 trawler: spacious, stable, unsinkable
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Old 22-03-2018, 10:52   #11
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re: Making Voyages on twin gas engines ?

My vote goes for low speed and alternating engines.

Low speed because the amount of power / knot is much lower than when getting up to the hull speed and even when planning. Alternating engines because the fuel consumption at low power is very definitely dependent on load. Higher load results in much lower fuel consumption in terms of g/kWh (lbs/hp.hr?). One engine is by definition running at twice the load.

Have a great holiday!
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Old 22-03-2018, 11:54   #12
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re: Making Voyages on twin gas engines ?

Hi Al B,

I've owned several similar boats and previous comments from Valhalla and others is exactly correct. 12 kts is terrible speed for a boat like that. Worst handling, biggest wake and absolutely the worst gas mileage.

That boat will go best at no wake speed, 6-7 kts max or up on a clean plane which I'm guessing will be 25-28 kts.

I think Denverd0n's recommendation is the best. If you want to save fuel go slow, use both engines but every couple of hours or so when you're in an open area and speed is allowed, open up for a while to blow it out.

But bottom line, if you're trying to save fuel, tow it down.
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Old 22-03-2018, 11:54   #13
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re: Making Voyages on twin gas engines ?

12kts on one engine is going to be higher in the rpm's than you think. I had an express cruiser of the same size for 10 years. There are two sweet spots for fuel burn 8 kts and 20 - 23 kts. 14 kts used to burn MORE fuel. I doubt you're truly on plane below 18 kts. 12-16 kts you're plowing water, putting tons of load on the engine and wasting fuel.

For a long trip, run both engines down around 8 kts if you want to burn fuel. You could try it with one and either alternate days, or run one engine out and the other back.
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Old 22-03-2018, 15:00   #14
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re: Making Voyages on twin gas engines ?

If I were to retire on a power vessel this would not be the type I could afford to run.

I am sure there are people who are not retiring and whio would LOVE to own such a vessel as yours.

My ideal retirement floating palace is a modest catamaran type with twin diesel engines with or without sails. Both types exist--but for peace and enjoyment--the time the sails draw nicely and I can turn off the diesel engine, the better the trip becomes.

Sailing is not for everyone though--but comfort usually is--and SPACE aboard is always good to have. I can get almost anywhere I wish to go at ten knots--but under sail it is usually about six to seven knots with a good breeze,. That is about the most economical speed for your engines--except that my vessel cost only the wind for fuel once sails were set---and it would do your economical speed on its own engines at a fraction of the fuel cost.

Also--the maintenance on a forty foot cat is going to be less than that for your current or proposed powered vessel or about the same depending on where you are moored.


I think selling her is a good idea--but it is your decision--and in retirement every dollar matters a great deal regardless of how many of them one has accrued.

From where I sit, the only advantage to your vessel is being able to tow it home over the winter or for extended maintenance.

So--you want to consider sail or a trawler type of powered vessel?

I like sail--but there are as many advantages to a comfortable diesel powered displacement cruiser if one wishes to live aboard full time as there are for a sailing vessel. Sometimes fishing vessels can be bought at a good price and converted to a comfortable floating home.


I think you need to experience both--but hiring a forty-foot sailing vessel for a weekend might give you some idea about space and life aboard in what, compared to a house, will seem like cramped conditions. I would advise trying out all types so that YOU are familiar with them--because all of us are biased--in my case towards sail.


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Old 22-03-2018, 15:48   #15
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re: Making Voyages on twin gas engines ?

I ran a 34ft Luhrs with twin 454 Crusaders waste of time trying to run one engine the thing will handle like a pig . The answer I found was 1325 -1400 rpm that is about 5-7 knts there is virtually no noise or vibration and you can have a conversation. Fuel consumption was not much more than a Diesel. If you think you will run it at 25knts or on the plane ,you need to load your Dink with fuel containers and earplugs. Also, are you in a hurry to get somewhere???
You are retired your time is your own! Take your time to enjoy the trip.
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