Cruising speed...

[psneeld]

My boat isn't a toy.

It is a home, it is a vacation home, it is a means of transportation, it is a vacation destination for family and friends....probably more but I made my point that some posters just never see past their own life.

 

[BandB]

My boat isn't a toy.

It is a home, it is a vacation home, it is a means of transportation, it is a vacation destination for family and friends....probably more but I made my point that some posters just never see past their own life.

Wifey B: There's a world of people out there different from you or you or you or you or any of us. We know we don't fit the normalcy of the TF group, but then that's part of pleasure too of learning how others feel and how they do things. I like KK's and some other slow boats, just not for me. But I still appreciate them. I think of our boats as homes, because we often have such incredible times with our extended family. One other thing your boat is. It's a PLEASURE BOAT. That's why we all have them. PLEASURE. And each of us achieves it differently but that's the goal.

 

[psneeld]

Pleasure is just a fraction in my boating world....

Necessity (way of life) for me, pleasure for many.

My point is that some feel the necessity to always say those different from them have the wrong boat or don't operate it properly....don't know why...wield to me as I have been fully immersed in boating in all aspects for quite awhile...not just something between trips or other entertainment.

 

[Al]

Frequent debate, time vs money. Bay Pelican gets 4mpg at 6.5 kts and 2.5mpg at 7.5 kts.

We pay Caribbean prices for diesel, perhaps $5 US per US gallon.

On an 80 mile run, the time difference is an hour and a half while the cost difference is $60 US.

Here is a point that often is not addresses. Time, Distance, speed, pick two.

With comfortable fly bridge weather, the pleasure of slipping along at 4 kt. at 1000 RPM enjoying the day as well extend the time of boating, makes the voyage pure pleasure. Particularly if as we are blessed here in Southern Southeast Alaska, the depth next to the shore, (say 50'max from the shore) is in the hundred plus feet deep, running as close as one can in and out of the bits and pieces of bites/coves/grassy knolls is what pot holing is all about. Come join me some voyage under those conditions, the wine or cold beer can't taste any better. (These conditions fuel burn wise, present almost "Free Fuel" use.

Al-Ketchikan

 

[ranger58sb]

But if one is regularly running a boat under or above the designers intent the question of "do I have the right boat" should emerge.

"Yes" is an acceptable answer.

-Chris

 

[Joebad]

A boats speed is often broken down by cruising speed and maximum speed. Maximum speed is self explanatory but I need help in defining what is cruising speed, is it the most efficient. If a boat is described with a cruising speed of 12 knots what is the effect of going 8 knots, is it less efficient at that speed?

The slower you go the better the mpg. My 34 Swift trawler burns 1.2 lph at 3.5 kts. 3.8 lph at 6 kts. 8 lph at 7 kts. 12 lph at 8 kts. 76 lph at 21 kts. We run 90% of the time at 6 kts. The longer your hull the faster your most practical running speed. My boat has a 6.7 Cummins with 425 hp and a 25" Prop and 32' waterline.

 

[smitty477]

""Yes" is an acceptable answer.
-Chris"


I could not agree with you more. We have used our boats similarly in that they have a very large range of speeds at which they can reasonably be run. And even if you use your examples of 6 knots 75% of the time and 24 knots 25% of the time you have a pretty even split of how much distance you travel at each speed. It is really a great advantage to be able to select from a wide range of speeds the way we boat with the large tides and changing sea states we often encounter.

 

[Art]

Quote: Originally Posted by Nomad Willy View Post
Eye,
7 to 20 knots?
I'd call it closer to 10 to 14.
If you're going 7 or 20 knots you've got the wrong boat.
Just because a boat can do something dos'nt mean you should do it. Especially over long periods of time.
Many of us have the wrong boat but it's expensive to change.

Wrong is maybe in the eye of some beholders.

Just cause a boat can only do one thing doesn't mean it'd be right for everyone.

We can run comfortably from 6-24 Kts. We usually translate that to about 8 kts or about 19-20 kts. Depends on our mood, destination, time available, sea states, etc... so probably about half and half...

It's a right boat for us.

-Chris

I primarily agree with Chris...

On another vane - I like to call it "Captain's Speed" / Rather than "cruise speed".

IMO - Any speed the Captain is having the boat travel for elongated duration [an hour or more] at any point in time IS a cruise speed. The speed of travel [i.e. cruise speed], depending on a myriad of items such as hull design, gross weight, sea conditions, power options... and on and on... is as the Captain believes is correct at the time.

Simple Rule of Thumb [for most any boat]: Faster Captain cruises the boat, faster the Captain empties her fuel tanks.

With all that's been said so far in this thread and having to do with what I said above. In basic similarity Chris's likes [i.e. Captain's desire for type of boat] I'll state what I like in a boat regarding the type cruising I currently am into.

Planing hull is what I require. Because... I can go relatively quickly at 17 knots on full plane and get about 1 knot per gallon. That means I can cover about 85 miles in roughly 5 hours... not too bad at today's fuel costs which means I will have spent some $255 in fuel... but we get there quickly and have more time to enjoy the destination. I can also put the engines [another item I like to have is twins] up onto higher rpm for a while and travel in the low 20 Knot range if I need to for any reason. Fuel burn at that speed is of course more per knot traveled. On the other hand - I can slow down to below hull speed and travel at 6.5 to 7 knots [7.58 is calced hull speed for our boat] getting 2 + nmpg. If we really want to take our time... I shut one engine off, reduce speed to about 5 knots and get around 3 nmpg.

Soooo - The "Captain 's Speed" is what ever speed the Captain wants the boat to travel at [i.e. cruise speed]. Each boat and its Captain match has different requirements/opportunities. Very important thing is for the Captain to "know" the boat... then while cruising the boat will get to know the Captain!

BTW: In the long-range scale of costs for owning a boat, unless you are putting umpteen hours annually on the engines, fuel cost is basically a blip on the radar regarding the so many "boat-cost" variables.

Happy Boat-Choice Daze! - Art

 

[ranger58sb]

But if one is regularly running a boat under or above the designers intent the question of "do I have the right boat" should emerge.
I do'nt for example but it's an economic issue for me.

"Yes" is an acceptable answer.

Another way to think on it.

What if you actually wanted to be able to travel on a boat at speeds ranging from 6-20 knots?

How would you shop for likely candidate boats? What boats would you expect to emerge from your search? Would you expect some of those were actually designed to meet those criteria?

-Chris

 

[alormaria]

My boat has two speeds: Slow and Stopped.

Three if you count Reverse which would be negative speed?

I can't wait for the snow to melt.

 

[Nomad Willy]

Chris,
If I wanted to go 6 knots most of the time I'd get a FD boat and go 6 knots. If I opted to get a boat that went 24 knots some of the time I'd either admit I was running my boat in a way it was not intended.

However there are boats that come close to running 24 knots some of the time and 6 or maybe 8 knots most of the time. Consider a long narrow boat w three engines, shafts and props. In order to do the 6-24 you're going to have to sacrafice big time at one end .. or optionally both. So if you went into a NA office and asked for a design to go 6 and 24 knots 75% of the time 6 the NA would probably come up w a boat very different than your boat.

Again not running the boat the way it was intended to be run means you have the wrong boat. An excellent example would be having a GB 36 twin and running it 6 - 7 knots. You've got the wrong boat. The GB 36 single would be far far better. But the GB 36 has a hull that is not suited for 6 knots so you've still got the wrong boat. Of course marketing is heavily involved in this example. If I wanted to go 7-8 knots the GB 36 twin is probably the right boat but all the extra weight and expense would need to be justfied to get the twin.

With my own boat I could go 5 knots 75% of the time and 7 some of the time but in this example I would always have the wrong boat.

 

[Nomad Willy]

Wifey B: Oh my. You're missing the point with all this designer's intent stuff. The designer's intent is that you run it at any speed your little heart desires. The designer doesn't care if it's 8 knots or 20 knots. They designed it to do all.

WifeyB,
I am NOT missing the point. I am MAKING the point that is being missed.

These toy boats obviously can be run any way one wants. Even in ways the designer never intended. The're pleasure boats and what ever gives us pleasure is acceptable to us but because one does it and likes it dos'nt make it right. If there's other boats that come much much closser to one's actual use then they should have one of those boats.

 

[smitty477]

"The're pleasure boats and what ever gives us pleasure is acceptable to us but because one does it and likes it dos'nt make it right. If there's other boats that come much much closser to one's actual use then they should have one of those boats."


I am not sure I have this correct - I want and/or need to go 18 knots at times but most of my main engine hours will likely be at a speed of maybe 6 knots.
In the large picture the actual distances covered will be mostly at the higher speeds but not the actual hours.
Should I 'have' a boat that comes closer to the hours use then?

 

[BandB]

WifeyB,
I am NOT missing the point. I am MAKING the point that is being missed.

These toy boats obviously can be run any way one wants. Even in ways the designer never intended. The're pleasure boats and what ever gives us pleasure is acceptable to us but because one does it and likes it dos'nt make it right. If there's other boats that come much much closser to one's actual use then they should have one of those boats.

Wifey B: The audacity of nomad never ceases to amaze me, that you personally feel you have the right to dictate to the entire world what the designer, who you've never talked to or met, intended, and what boat each person should have. You don't get that just because you feel a certain way doesn't make it gospel and that imposing your prejudices on others isn't right.

And yes, doing what we want to with out boat 100% makes it right. Right is in the eye of the beholder, not some judgmental third party.

Your use may be the same all the time. The rest of us may actually like variety. The spice of life, you know.

Ok, this morning, I ran at 10 knots from the marina to the inlet, 20 knots through the inlet, 35 knots outside? Which, is right as god or you intended?

Never going to buy into your dictatorial what you say is right is right philosophy. Sorry.

 

[BandB]

"The're pleasure boats and what ever gives us pleasure is acceptable to us but because one does it and likes it dos'nt make it right. If there's other boats that come much much closser to one's actual use then they should have one of those boats."


I am not sure I have this correct - I want and/or need to go 18 knots at times but most of my main engine hours will likely be at a speed of maybe 6 knots.
In the large picture the actual distances covered will be mostly at the higher speeds but not the actual hours.
Should I 'have' a boat that comes closer to the hours use then?

Wifey B: I've got it (in a very cockney accent). By George, I think i've got it. You should let Nomad pick out your boat for you.

And your anchor.

 

[eyschulman]

A lot of to-do about nothing. We travel at the seed we want or can that's it.

 

[Northern Spy]

I am NOT missing the point. I am MAKING the point that is being missed.

Wow.

You ever hear of the concept of turndown capacity or operating envelope?

What about a bass boat that travels 75mph to get to a spot and then does 1-2 mph on a trolling motor?

Do you have a highway car and a 'round town car?

Do you have a separate toaster for bagels, bread, poptarts, and waffles?

 

[psneeld]

Thank you WifeyB and Northern Spy......

 

[Al]

Quote:

BTW: In the long-range scale of costs for owning a boat, unless you are putting umpteen hours annually on the engines, fuel cost is basically a blip on the radar regarding the so many "boat-cost" variables.

Happy Boat-Choice Daze! - Art

Art has nailed it!

Al-Ketchikan

 

[Nomad Willy]

Another way to think on it.

What if you actually wanted to be able to travel on a boat at speeds ranging from 6-20 knots?

How would you shop for likely candidate boats? What boats would you expect to emerge from your search? Would you expect some of those were actually designed to meet those criteria?

-Chris

Chris,
Another good point.
And to call out or plan such a design why would you want to go 6 knots most of the time? Your boat design should be centered around that. And also why would want to go 20 knot -art of the time? And when you decide what is more important you look for designs that deliver a design that's slanted that way.

 

[psneeld]

I can't think of one boater I have ever boated with that wouldn't like to go much faster at some point... beat darkness, a storm, get to the fuel dock before it closes...

Sure it's not always possible, but I can't think of one person who wouldn't want it if it was possible.

For my boat, it's not possible so I have the 6.3 knot mentality....but if I could do 20...I would love it and do it occasionally, not all the time.


Doing the AICW, there are so many slow speed zones, ALL fast boats spend a lot of time at 6 knots anyway. But being able to cruise the open spots at 20+ is sure nice.....as there are no snow capped mountains to oogle.

 

[Nomad Willy]

Wow.

You ever hear of the concept of turndown capacity or operating envelope?

What about a bass boat that travels 75mph to get to a spot and then does 1-2 mph on a trolling motor?

Do you have a highway car and a 'round town car?

Do you have a separate toaster for bagels, bread, poptarts, and waffles?

OPERATING ENVELOPE
That's a good one and the NA for most designs would probably call that out.

Ideal speed?
If one started from there and went higher and lower through the acceptable speeds I would imagine the "operating envelope" would be established. To operate in this range one should'nt need to question if they have the right boat. Then there's the other speeds like entering port but this thread is about cruising speeds. One could call the acceptable speeds or cruising envelope the boat's cruising speed range. Bass boats, toasters or cars need not apply. The analogy is good for laughs but not applicable to the question.

 

[dhays]

I can't think of one boater I have ever boated with that wouldn't like to go much faster at some point... beat darkness, a storm, get to the fuel dock before it closes...

Sure it's not always posdible, but I can't think of one person who wouldn't want it if it was possible.

For my boat, it's not possible so I have the 6.3 knot mentality....but if I could do 20...I would love it and do it occasionally, not all the time.

I agree. I would like to have a boat that was efficient at 7 knots yet be able to run at 15-20 knots when I wanted. I could have even bought a boat that could do that. However, since there are always trade offs, I decided that the ability to go faster wasn't worth the trade off for me.

I think I understand what Nomad is saying. If I wanted to always run at 10 knots, my boat would likely be the "wrong" boat choice. However, the PO says he ran the boat that way all the time. My boat just isn't efficient at that speed. Likewise, if I never wanted to run above 7 knots (I mean NEVER), then I also would have bought the "wrong" boat because the boat is way overpowered for that speed and the hull isn't as efficient as a FD hull of the appropriate LWL.

If I was always going to have 3 couples on board, my boat may be the "wrong" boat. If I were to only very occasionally have 3 couples on board, my boat is just fine. If we were never going to have guests on board, my boat would be overkill for its use, therefore the "wrong" boat.

Having the "wrong" boat for a given application doesn't mean someone made a bad choice or should have picked a different boat. We buy what we like and we use it as we wish and there is nothing "wrong" about that. However, it is probably a good thing, particularly for a new potential buyer like the OP, to carefully consider how they want to use the boat before they buy one.

Northern Spy has it right. A boat's operating envelop should cover everything you need/want and comfortably cover what you use the most. So if I want to be able to cruise between 6-10 knots but spend most of the time between 6.5-8 kts, the my boat is a good choice. If I wanted 6-10 kts but want to spend most of the time at 10 kts, my boat's operating envelop covers that, just not as well as another boat choice would have been.

 

[Nomad Willy]

Wifey B: I've got it (in a very cockney accent). By George, I think i've got it. You should let Nomad pick out your boat for you.

And your anchor.

WifeyB,
Thanks for the confidence WB.
Better a NA do that.
But I already called out some features to look for.
The high speed requires lightness. Something usually not found in a trawler. Fewer gensets, a lighter one or none at all. A lighter engine ... probably higher rpm. Less glass. Smaller keel. Less fluids ect ect. All boats (speed wise) pay a price for weight. FD far less, SD less to more depending on design, and planing much much more. Ect ect.........
A narrow beam at the W/L and a QBBL most suitable for the highest speed and if the lower speed is more important a slight increase in QBBL angle. Narrow beams decrease angles of attack and decrease drag at low speeds.
Trim optimized for the higher speed as getting "over the hump" may be problematic.

The above shows the idea. So a reasonably good compromize design can be had. But just going out and buying what turns you on and doing whatever with it is ok as you the boat owner are the only one paying the price.

My own philosophy is just to ditch the 12 knots that I'd like to do as too expensive and go everywhere at 6 knots. Works for me.

For those that want to "have the cake and eat it too" just have to pay the price.

 

[BandB]

The high speed requires lightness. Something usually not found in a trawler. Fewer gensets, a lighter one or none at all. A lighter engine ... probably higher rpm. Less glass. Smaller keel. Less fluids ect ect. All boats (speed wise) pay a price for weight. FD far less, SD less to more depending on design, and planing much much more. Ect ect.........
A narrow beam at the W/L and a QBBL most suitable for the highest speed and if the lower speed is more important a slight increase in QBBL angle. Narrow beams decrease angles of attack and decrease drag at low speeds.
Trim optimized for the higher speed as getting "over the hump" may be problematic.

.

Wifey B: So, my current boat lust weighing 100,000+ lbs unladen and 141,000 fully laden with a 21'9" beam, 3170 gallons of diesel, 528 gallons of water, 2 generators, watermaker, 12 people aboard, running 58 knots WOT and cruise of 50 knots is impossible?

Oh and my car will run 190 mph but does just fine at 35 and 55 and 75 although the people who built it are all going to jail jail jail jail.

 

[Northern Spy]

OPERATING ENVELOPE
That's a good one and the NA for most designs would probably call that out.

Ideal speed?
If one started from there and went higher and lower through the acceptable speeds I would imagine the "operating envelope" would be established. To operate in this range one should'nt need to question if they have the right boat. Then there's the other speeds like entering port but this thread is about cruising speeds. One could call the acceptable speeds or cruising envelope the boat's cruising speed range. Bass boats, toasters or cars need not apply. The analogy is good for laughs but not applicable to the question.

So you DO have four toasters.












I knew it.

[emoji3]

 

[BandB]

So you DO have four toasters.












I knew it.

Wifey B: And he has 27 anchors.

 

[psneeld]

This is so increadible...semi-displacement boats in the right configuration are exactly the "versitile boat" that someone might think is the "wrong" boat.

Their concept is to be able to run fast when lightly loaded or when appropriate...and still be a decent boat at displacement speeds.....or really any speed in between.

A good example is a working boat like a lobster boat. It runs and guns as long as it can so the day doesn't last forever, as it fills with catch or pots, it may slow, but throughout its range it isn't killing the operator on fuel costs like a true planing hull would. A displacement only boat wouldn't work either.

The same principles might apply for a cruiser too.

So yes....a displacement boat can only do one tiny speed range...but a semi-displacement has quite a bit of speed range that the designer DID think about...and there are those with planing boats that know if they do slow to a displacement like speed, their boat isn't all that ineffecient.

Maybe that feature isn't a specific design feature...but both the designer and operators know it's there if they want it.

 

[markpierce]

Semi-displacement boats usually have smaller rudders.

 

[psneeld]

Semi-displacement boats usually have smaller rudders.

Like most things in boating...it depends....