How slow is too slow? (long)

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ksanders said:
Doug, you are at a stage in life where you have more money than time. You and your wife are both working, bringing in income. That makes your time limited.

For you right now going quicker more often is the right thing to do.

At some point things will change. You will retire and have more time than money. Then you might choose to go slower, enjoy the sights more, and save some money on fuel costs.

Some here have indicated that fuel costs are a small part of boating. That is correct if you are a weekender, but not if you choose a cruising lifestyle in retirement. Then the difference in fuel costs over the long term can be staggering.
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Great post!
 
Dougcole said:
Do many trawler owners take the pursuit of as little fuel burn as possible too far? Yes!

My thought was "why bother leaving the dock? Stay there and burn nothing at all. :thumb:

Are you sacrificing enjoyment of your time on the water to save just a few dollars on fuel?
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I agree! Too much emphasis is placed on slowing way down to save fuel. When we drive our cars, most of us go the speed limit or more but when we get in our boats, then we decide it's time to save money??? :facepalm:

Yes, too much is made of seeing who has the least fuel burn. I'm not impressed with any of it.
 
markpierce said:
Transiting a no-wake zone (within 200 feet of a docked boat, etcetera) at a bit over 4 knots must be a pain. :eek:
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I just about blew beer out my nose on that one!
You OBVIOUSLY have never seen SeaRay operators running on the Columbia!... no wake zone?? what no wake zone?? oh wait ... I WAS a SeaRay owner until recently!...


HOLLYWOOD
Recovering ex SeaRay owner
Enjoying life at 8kts. again via Ocean Alexander
 
Walt wrote;

"I agree! Too much emphasis is placed on slowing way down to save fuel."

I agree w that too. Many do it just because lots of other guys are doing it. Kind of a fad. When the prices of FD boats goes up because of their good fuel burn rates I'll know it's a "real" problem.

As to how slow is too slow in the fall in SE Alaska we had a big problem getting where we wanted and more or less needed to go because of limited daylight hours. I'll run in the dark from time to time but not on a regular basis. It would take 2 days to go from Thorne Bay to Petersburg but if the tide was not right it took even 3 days. At some point in the winter the whole tide run was in one direction and then w my 6 knot boat we just couldn't make it at all.

But during the summer 6.15 knots has never been a problem. But one must be patient to go 2 knots sog for over 2 hours at a time. So re the OP 6.15 knots is not too slow for us. Except in the winter in SE Alaska. And we are no longer there.
 
Nobody mentioned range. When I cruised my 40knt boat, at 24knts my whole trip was planned around my next fuel stop. Now when I cruise my 10knt boat at six knts, I can cover close to 4000 miles between fuel stops. I go where I want to go, not to the next fuel. Slow
speed is limiting if you are a weekend boater, but then that's why they make Sea Rays and Bayliners. In fact one of those fuel efficient 60' Fountain cruisers that can knock 60 plus knts just might be the ultimate weekend warrior . This weekend I was doing 60mph on the levee when one of the go fast cruisers past me by at least 15mph. Pretty good looking crew as well. Oh well, I guess you can't have it all.
 
I agree! Too much emphasis is placed on slowing way down to save fuel. When we drive our cars, most of us go the speed limit or more but when we get in our boats, then we decide it's time to save money??? :facepalm:

An extra 5mph in a car going over 55mphis small , an extra 20 mph is onlt about 10% bigger burn..so what?

The difference between 6K and 10K may be 300% in fuel burn.
 
SeaHorse II said:
I agree! Too much emphasis is placed on slowing way down to save fuel. When we drive our cars, most of us go the speed limit or more but when we get in our boats, then we decide it's time to save money??? :facepalm:

Yes, too much is made of seeing who has the least fuel burn. I'm not impressed with any of it.
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You must not drive a Super Duty pickup truck.. Many times I keep it at 60 instead of 75 like the traffic allows and I save 25% in fuel costs.

Sure it doesn't matter going a mile or two to the store...just like on a boat it doesn't matter at 50-100hrs a year...start cruising 300-500 hrs a year (or burning over 3000 galons/year) and it starts to matter as does it can mean just making the next fuel stop.

None of it's meant to impress any more than some of the REAL nonsensensical threads on this sight...like smoothest engines....discussing fuel consumption issues are just to let the less informed that cruising boats save significantly when run certain ways.

Most of the old timers hardly need to be on this forum having already formed their opinion (right or wrong) and probably aren't going to change ant boating habits (even when pretty reliable, factual sources are linked).
 
The difference between 6.3 (a knot below hull speed) and 7.3 knots can be on the order of 75% increased fuel use.
 
psneeld said:
Most of the old timers hardly need to be on this forum having already formed their opinion (right or wrong) and probably aren't going to change ant boating habits (even when pretty reliable, factual sources are linked).
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I disagree with your sweeping denouncement of our respected elders. Most of the folks I've met here, old and young, seem to be willing and eager to share what they know and learn from others' experiences.

Do you include yourself as "most of the old timers"?

I'm not one of 'em yet, although I may resemble that remark. :whistling:
 
FlyWright said:
I disagree with your sweeping denouncement of our respected elders.
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My statement that I think too much is made of going slow stems mainly from the fact that most of my cruises beyond 50 miles (one way) were done when I was paying $1/gallon. Now, that fuel is sky high, I don't go nearly as far. I still believe, however, that too much is made of going slow. I use to make the trip to Catalina in 3.5 hours. (Ocean Alex @ 20 knots) In my present boat it would take me 8.5-9.0 hours. With me it's the destination not the journey. :blush:
 
The Eagle is to slow and one of hundred of reason we do not leave the dock much. Ok, seldom!:D I personal what to buy a go very fast boat, but my wife wanted the ugly slow trawler, which has made a great live a board. Being we both work and family, friends and personal stuff take up most week ends and vacations. At least every month we are fly/going someplace. Besides since we live on the boat why in the heck would we want to take a vacation on it? :confused:

The plan when we retire is to move the boat around the PNW as we will not be tied to one area. We been talking about moving the boat to where its drier and warmer. PNW can be so damp and depressing!
 
FlyWright said:
I disagree with your sweeping denouncement of our respected elders. Most of the folks I've met here, old and young, seem to be willing and eager to share what they know and learn from others' experiences.

Do you include yourself as "most of the old timers"?

I'm not one of 'em yet, although I may resemble that remark. :whistling:
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We seem to disagree then.

My opinion didn't denounce anyone...that's YOUR interpretation of my comment.

"old timers" doesn't necessarily have anything to do with age.....
 
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Some of us have limited budgets, some of us don't.
Some of us have tight schedules, some of us don't.
Some of us have go slow boats, some of us don't.
Some of us see each other as old, some of us don't.
It's what makes the world go 'round.

If you play or cruise or live or do whatever on a boat... you're luckier or crazier (or both) than most. We only come by once, and only for a short ride. Enjoy the heck out of that ride, however you see fit.
 
Going slow is peaceful.

 
In Boating - Simply Going Is Life Extending... At Any Speed!

:thumb::thumb::thumb:
 
I agree with Art, being out there and enjoying the day is the biggest plus, regardless of what speed you are doing.
Every one has different agenda when it comes to boating, so maybe if we are happy in ourselves for what we enjoy and can afford , than that is all that matters. :thumb::thumb:

I just wish I was boating in the states where Fuel is so Cheap !!!:socool:

Cheers Chris D Liberty
 
I would like everyone's (or anyone's) opinion on what is too low an rpm for diesel engines. Do I understand it that manufacturers set a suggested cruising speed at around 75-80% of WOT? I realize that there is a minimum temperature required to burn the fuel completely, but is temperature the only restriction? On the following engine for example:
Detroit Diesel 12V71N
WOT is 2300 rpm and fuel burn is 28 gph
at 78% (cruising speed) rpm is 1800 rpm with a fuel burn of 14 gph
at 52% rpm is 1200 rpm with a fuel burn of 6 gph

My question is, if the engine temperature stays above 150 or so, can you cruise at 1200 rpm without damaging the engines? I'm asking about long term damage if you chose to cruise at these reduced speeds throughout the life of the engine. Obviously, you would need to blow them out for a few minutes periodically throughout each cruise.
 
The 75-80% figure is mostly related to engine longevity. For a lot of engines you might even be able to run 90% WOT continuously. What the engine guys are warning about is don't try and run near WOT for extended periods.

A comfortable cruise speed is more boat hull & weight related, and it might be at a much lower engine power level than 80%.

For DD's, they get their best performance (fuel efficiency and longevity) when reasonably loaded up. Running them at low loads is not ideal, but I think there are quite a few owners here who do and have not had the sky fall in. One of them can comment on the 52% load level but doing that with a run-up from time to time is pretty common practice. I think that if you have DD's then running on just one engine at slow speeds, in order to load the other one up a bit more, does have merit if your hull still behaves ok.
 
Fifty two % of rpm is only 15 or 20 % load.

18-1900rpm may be 50% load. depends on what rpm you burn 50% of the maximum amount of fuel your engine can burn under a propper load.
 
Insequent said:
The 75-80% figure is mostly related to engine longevity. For a lot of engines you might even be able to run 90% WOT continuously. What the engine guys are warning about is don't try and run near WOT for extended periods.

A comfortable cruise speed is more boat hull & weight related, and it might be at a much lower engine power level than 80%.

For DD's, they get their best performance (fuel efficiency and longevity) when reasonably loaded up. Running them at low loads is not ideal, but I think there are quite a few owners here who do and have not had the sky fall in. One of them can comment on the 52% load level but doing that with a run-up from time to time is pretty common practice. I think that if you have DD's then running on just one engine at slow speeds, in order to load the other one up a bit more, does have merit if your hull still behaves ok.
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I've yet to find a DD mechanic, and I've met several old timers, who can remember one failing due to going too slow. No load is the problem and not recommended. Yeah you run them up for 15 minutes at the end of a day's slow run, or maybe the next day's slow run or heck just every now and then. Our 8v92ti's spent almost all their life between 1000 and 1300 rpm and surveyed beautifully at 3000+ hours.
 
Cuttyhunk47 said:
I would like everyone's (or anyone's) opinion on what is too low an rpm for diesel engines. Do I understand it that manufacturers set a suggested cruising speed at around 75-80% of WOT? I realize that there is a minimum temperature required to burn the fuel completely, but is temperature the only restriction? On the following engine for example:
Detroit Diesel 12V71N
WOT is 2300 rpm and fuel burn is 28 gph
at 78% (cruising speed) rpm is 1800 rpm with a fuel burn of 14 gph
at 52% rpm is 1200 rpm with a fuel burn of 6 gph

My question is, if the engine temperature stays above 150 or so, can you cruise at 1200 rpm without damaging the engines? I'm asking about long term damage if you chose to cruise at these reduced speeds throughout the life of the engine. Obviously, you would need to blow them out for a few minutes periodically throughout each cruise.
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I like to run my 3208 cats at 1200 rpm burning 4 gal/hr @ 7 kts (160 degrees). I can barely hear them running. Every few hours I run them up to 2000 rpms for 5-10 minutes. I only get about 11 kts at that rpm. When I throttle up a blue puff of smoke comes out but clears quickly. Engines heat up to 175-180 degrees and all is well. The wind is more and isenglass flaps around and its louder. I like slow better. I have a great mechanic (Ski on this forum) which instructed me to do this.
 
Some of you may have heard this from me before. It is my explanation of why I run slow.
I am simplifying the numbers as fractions are difficult to follow.

We have a number of jumps which are approximately 65 nm. Generally I do these at 6.5 kts, way down from our higher cruise speed of 8kts.

However at 6.5kts we burn two gallons per hour, at 8kts it is close to four gph, almost double.

Thus for a 65 mile trip:

6.5 kts, 10hrs, 20 gallons burned at $6 per gallon (Caribbean prices) $120 US
8 kts, 8 hrs, 32 gallons burned at $6 per gallon, $192 US

Since we will leave at approximately 6 am in all conditions, the difference in arriving at 2 pm, or 4 pm is $72 US, more than enough to buy us dinner.

This may or not be important to all of us, but I consider it a free meal for an extra two hours of watching the world go by.
 
Magnawake said:
I have a great mechanic (Ski on this forum) which instructed me to do this.
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You're a lucky man! I wish I had a Ski on the left coast. :smitten:

Bay Pelican said:
This may or not be important to all of us, but I consider it a free meal for an extra two hours of watching the world go by.
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Shucks....2 more hours in that KK42. Don't you hate it when that happens? :D
 
Bay Pelican said:
...
Since we will leave at approximately 6 am in all conditions, the difference in arriving at 2 pm, or 4 pm is $72 US, more than enough to buy us dinner....
Click to expand...

As I said a few days ago. :thumb:
 
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