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Old 01-19-2015, 12:12 AM   #21
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Our Tolly can easily cruise at 16/17 knots and hit 21 plus if desired. She can also lope along at economical hull speed or below. All that is just what I want her to be able to do!

One of the many reasons we purchased.

Different strokes fer different folks!!
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Old 01-19-2015, 12:25 AM   #22
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Marin I'm talking about a good boat design. You think it has something to do w sales and you're right. But because people by a boat dosn't make it a good design. People buy all kinds of bad products. If we knew everything about all the stuff we buy there would probably be a lot we'd Huck out.

You guys just think you need all that power. Why is it that you all need that power and I get along gracefully without it.
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Old 01-19-2015, 12:52 AM   #23
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Engine size when using twins

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Originally Posted by manyboats View Post
You guys just think you need all that power.

No you're just looking for an argument Eric.

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Why is it that you all need that power and I get along gracefully without it.

Because I enjoy traveling faster than you do? Because there's perhaps 1 full displacement power boat for every 500 semi-displacement boats on the water?

Apples and oranges Eric, comparing a Grand Banks and a Willard hull is akin to comparing a Camry to a T-100 pickup.

PS, it has everything to do with sales because nobody builds used boats. They build new boats to sell to folks with the disposable income to buy them.
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Old 01-19-2015, 12:52 AM   #24
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All that matters is that you like your boat. My 80-horsepower engine is nicely balanced pushing the full-displacement Coot's 14 tons economically a knot under hull speed at 1800 RPM and reaching hull speed at 2200 while the engine has a maximum rating of 2400 RPM. See no advantage of over-propping or having additional horsepower in my situation.


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Old 01-19-2015, 01:11 AM   #25
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When I go out in my old 1990 GT4, it has the potential for 220kph, but I (nowadays 'cause I'm respectable), never, well, not intentionally, exceed our limit of 100 or 110 kph. I'm sure the engine just loves that, as it still uses virtually no oil, and it has clocked up 300,000 mms.
I just finished a shoot in Taiwan at which one of Boeing's top service engineers was a consulting expert to the crew doing the work we were shooting. Thia guy, in addition to what he does for Boeing, lives and breathes performance cars and motorcycles. Stock cars, dragsters, motocross bikes, that sort of thing. He's not just an enthusiast, he builds or rebuilds them for a hobby.

At one point in the conversation one evening the subject of engine life came up. He made a statement which reinforced what I've heard from other very experienced mechanics and operators in the automotive, aviation and marine worlds. And that is that if you want an engine to last a long, long time, take it easy on it. The easier you make life for an engine, the less wear it will experience and the longer it will last.

I asked him what about the notion that engines need to be run hard, that that's what's good for them, they need that. His answer was one word: "bullsh*t."

He went on to say why in detail, but his basic premise was if you want an engine to last a long time, don't run it any harder than you have to.
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Old 01-19-2015, 01:18 AM   #26
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You guys just think you need all that power. Why is it that you all need that power and I get along gracefully without it.
Because for whatever reason you're satisfied with cruising your boat at the speed a turtle crawls and we're not. Slow sucks. That's basically what it boils down to. Our boat with the power it has only goes eight knots at the rpm we use, which is the best rpm for maximizing the life of the engines. But even eight knots is a hell of a lot better than six to our way of thinking. If our boat had been built with much more modern and more powerful engines we would run it at twelve knots. That would be way better than eight.

We're involved with a boat now that cruises at 30-35 knots. And I'm already beginning to wish we'd put more powerful engines in it.
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Old 01-19-2015, 01:30 AM   #27
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But because people by a boat dosn't make it a good design.
From whose point of view? Yours? You're living in a theoretical world where reality is of no importance. Or the point of view of the boat manufacturer, who's living in the real world of costs and payroll and taxes and profits? To him, your idea of a good design is his idea of a really crappy design.


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People buy all kinds of bad products.
Is a Fleming a bad boat? Is a Grand Banks a bad boat? Is an Eastbay a bad boat? Is a Krogen Express a bad boat? Is a Sabre a bad boat?

Theory doesn't mean squat unless it has a practical application. And in the world of production boats and the people who buy them, your low-horsepower, slow displacement boat concept is a non-starter because a) nobody but a handful of people want them and b) manufacturers are smart enough not to fool around making them if they want to capture as large a market share as they can.
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Old 01-19-2015, 01:35 AM   #28
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Yesterday reached a speed of 9.5 knots (with the boat at normal knot-below-hull-speed power) thanks to a three-knot favorable tidal current. Not a rare occurrence. (Reminds me of sailboat racing days fifty years ago where "playing" the currents was a major tactical concern.)
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Old 01-19-2015, 02:19 AM   #29
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Guys - - > Eric and Mark especially... but... for sure, due to words that have passed, Eric considerably more than Mark.

I've read every post in this thread. Bottom line as I see it, is that, I don’t really hear others telling you that you should have boats with more power… for some reason such as, “because you really don’t understand”…

Soooo, I recommend… Let IT Go! We all should simply enjoy the boats that please us at whatever speed(s) applicable.

Happy Boating Daze! - Art
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Old 01-19-2015, 02:58 AM   #30
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Bottom line as I see it, is that, I don’t really hear others telling you that you should have boats with more power....We all should simply enjoy the boats that please us at whatever speed(s) applicable.
Absolutely. Nothing wrong or bad about a boat that's low powered, slow, and economical if that is what a boater wants from a boat. Just as there is nothing wrong or bad with a boat with a pair of 500 hp diesels that cruises at 20 knots if that is what a boater wants from a boat. The high-powered, semi-planing boat design is bad if what a boater like Eric or Mark wants is a slow, economical, displacement boat. The slow, low powered displacement design is bad if a what a boater like me or Art or Peter wants is a cruising boat capable of faster speeds when needed or desired.

The notion that has been put forward in this discussion that a cruising boat design is automatically "bad" or "wrong" if it has more power than is necessary to creep the boat along at displacement or lower speeds and that its manufacturer has made a bad boat is bollocks as they say in the more civilized parts of the world. Every boat design, and every power to weight to hull design formula is right on the money if the resulting boat delivers what the buyer wants out of a boat.

The design and power of Art's Tollycraft is absolutely correct for the kind of boat Art wants. The design and power of our Grand Banks is not quite correct for the kind of boat we want because we wish it had even more powerful engines so we could cruise the hull faster than eight knots without making life harder on the engines. And the design and power of Mark's Coot is absolutely correct for the kind of boat Mark wants.

So I'm thinking it's time to put a bullet in the head of this notion that the only boat design that is correct is one with a displacement hull and just enough power to move it at displacement speed. It's certainly one viable option. But it's by no means the only viable option.
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Old 01-19-2015, 03:06 AM   #31
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Marin's post #30 reflects my opinion. Get/have a boat that fits your needs and wants. (I didn't move from sailboats to a motor vessel because I needed to travel faster but wanted a more reliable speed, with less physical effort, and a desire to move from an open cockpit to an enclosed pilothouse. Have been too exposed to ultraviolets already.)


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Old 01-19-2015, 08:06 AM   #32
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I was going to drop it as I figured I'd stated my position and others have re theirs. But there's more to be said and so little time. Going on a road trip Wed very AM for Edmonton Alberta so my input will be spotty but probably better than all these fast balls.

Peter B. wrote;
"I kinda like the fact that my Lehman 120hp is, by Eric's standards, over -powered,"
Actually that's not so Peter. The 36GB is under powered IMO but it's considerably bigger, wider and heavier than your 34CHB. Also I think the CHB hull is a tad bit more of a FD hull than the GB. So the 120FL seems to be plenty for the 34CHB and because of the over heating problem ect most won't run an FL very hard so in reality you don't really have 120hp. An 80 Cummins or old Perkins should do fine and that's about as much power as you have available. So no your CHB is not over or under powered IMO.


N4712 wrote;
"I too also like the reserve HP for those few times you need it"
Edelweiss wrote;
"We were crossing the straits of Georgia NewCastle Island to Welcome Passage in BC, running with a 42' single engine TT who only made about 6 knots.

Normally I wouldn't care about running slow, but the weather came up and we were getting our behinds kicked wallowing around in the slop with 20 miles of ugly highway ahead of us and three kids who were turning green. We started the second engine, wished the other skipper well, kicked it up to 11 knots and made the crossing in half the time.

Very thankful to have the extra speed on occasions like that!!"

That post brought about some new views of mine on the FD/SD differences.
I remember the "slicer/puncher" bit Mark brought to the forum some time ago. I think Mark knew more about what he was talking about than all of us did including Mark.
For years I've said I never needed more power when it got rough but over and over again many here said they did. I of course decided it was "all in their heads" and couldn't understand it. Cuz I certianly didn't need more power. I always reduce rpm in head seas and seem to make good headway for a 6 knot boat.
I suspect that my Willard is a slicer. I proclaimed it was a "puncher" because I thought her wake at speed wasn't really small. Now I think it is (a slicer (relatively so)) and that may be the reason Willy dosn't need more power in the nasty. Most trawlers have a much more blunt bow than Willy (as in PC) and I feel experience much more deceleration dealing w large head seas. And when the bow goes up the stern goes down and the stern (of a SD hull more like a planing hull) creates more drag than running level. This slows the boat down and most likely enough to require more than cruise power. Look at my pics of Willy's forefoot and perhaps it will appear to be a hull that can slice through waves w little inclination to be impeeded by them.
Edelweiss perhaps if you had a good FD hull you wouldn't have felt the need to go faster. If you had bigger rudders and a stern that didn't tend to yaw the boat around a lot and having kids turning green you may have been fine w buddy boating w the 42.

Marin wrote;
"Absolutely. If the boat won't sell, then it's a bad design. It's that simple."
I can't believe you (one of the smartest guys here) said that.
It's clear that if you were working for a boat builder you'd be better off on the marketing dept than in design and engineering. The latter seems to have escaped you.

Craig wrote;
"No you're just looking for an argument Eric."
No .. and I'm a bit offended by that. I'm just trying to express my opinions so people understand what I'm saying and not to have so many tomatoes fly'in by. Just trying to make my point. That is that speed is fine and mismatched hulls and engines (power) are not.
"Apples and oranges Eric, comparing a Grand Banks and a Willard hull is akin to comparing a Camry to a T-100 pickup."
Most of our boats are better looking than a Toyota PU. There I just compared them. An aircraft Carrier is in some important ways comparable to a row boat. Both FD hulls subject to the dynamics of hydraulic forces of physics to achieve the speed they do. ect ect.

Marin your post #25 is off topic.

Art I'm not telling anybody what boats they should have. I am, however pointing out that some boats are flawed re the powering issues. On The Rocks ... the OP wanted to know.
OTR you're right the smaller engines should be more efficient. Look for very close to 4 to 5 hp per ton of displacement while cruising. Just my opinion though.

Soldier on Mark and thanks for the "slicer/puncher" outlook.
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Old 01-19-2015, 09:16 AM   #33
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When one is enjoying the attributes on an over-propped, overpowered, full displacement hulled riverboat/trawler much pondering of "good design" occurs. I just spent 5 days underway dawn to dusk in such a boat. I am convinced once again of the positive attributes of over-propped, over-powered, full displacement. The over-propped 100 HP Westerbeke sips 1.5 gal. of diesel while providing a low level of background noise and 7 Knots at 1,600 RPM. I consider this level of performance GOOD! I could probably make 7 Knots with a Perkins 4-108 geared and propped to turn 2,800 RPM burning 1.5 Gal per Hour. But the last thing I want to do is live with a 4-108 turning 2,800 RPM all day.......And when the bridge ahead will be opening on a schedule I can push the throttle up to make 2,000 RPM and 8 knots and make the 11:00AM opening. Try THAT with the 4-108! Admittedly the Westerbeke specifications for WOT RPM cannot be met by my boat. And the negative effects have yet to be experienced as my engine is running at perfect temp, oil pressure, and without smoke. But as a benchmark a sistership has the same motor and propeller and is running strong at 10,000 hours. If my engine reaches this 10,000 mark I will either be dead or it will belong to someone else. And if my motor dies at 7,500 Hours because of over-propping that will be OK too. Because if I had to listen to a 35HP engine power my boat for even 1,000 hours I would have tied my Rocna anchor to my neck with chain and jumped overboard........
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Old 01-19-2015, 09:25 AM   #34
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Billyfeet,
In this case a CQR would work just as well.
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Old 01-19-2015, 09:29 AM   #35
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When looking for a boat, the choice was either slow, 7+/- knots (my boat now) or fast, 15+ knots. The thought that plowing along burning lots of fuel at 8 or 9 knots as opposed to 7 knots is just lost on me. As with Art's Tollycraft, if you want to go faster and pay for the extra fuel, then should be able to cut half or more of the time to your destination. Just don't get doubling or more the fuel burn to add a knot or 2.

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Old 01-19-2015, 09:53 AM   #36
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Why not have it all? The ability to economically cruise along at hull speed combined with the ability to kick it up to 10, 12 or egads even 16 knots when desired seems a very popular choice. Lots to choose from in this regard. If one is seeking the lowest possible fuel burn in a displacement pleasure vessel, well laid out sail boats are easy enough to find.

I'n headed to the Seattle Boat Show, wonder how many full displacement motor vessels will be there, other than very expensive Selenes or Nordhavns? Therin lies the rub, full displacement "new" is big bucks, which is not necessarily an overall cost effective way to travel. There is much more to economic boating than a low fuel burn per hour, much more.
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Old 01-19-2015, 11:26 AM   #37
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Therin lies the rub, full displacement "new" is big bucks, which is not necessarily an overall cost effective way to travel. There is much more to economic boating than a low fuel burn per hour, much more.
The cost of fuel is such a small part of the overall cost of owning a boat. I can't help but wonder why the average pleasure boater would be overly concerned about the expense. The difference between 3 gallons per hour vrs 5 gallons per hour is insignificant given the distances we travel. Unless you're a world traveler and constantly on the move. IMHO, the actual savings would be insignificant for me.

Reminds me of a friend years ago, who only bought cars with stick transmissions. At stop lights he turned the engine off, on hills he put the car in neutral rolling down the grade, and on longer down grade he also switched the ignition off all to save a little gas.
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Old 01-19-2015, 11:43 AM   #38
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Some of us easily travel 400 to 500 hrs per year.

The difference between 3 and 5 gph would be the difference of 1200 versus 2000 gal per year.

At $2 a gallon not so bad but when a lot of places it was over $4 a gallon ....that could easily be between $3000 to $4000 per year.

For many here that may not be a spit in the wind to their bank accounts...to others it's a new RIB or a genset or upgraded solar...etc...etc...

As many TF discussions...totally different audiences sometimes.
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Old 01-19-2015, 12:02 PM   #39
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When looking for a boat, the choice was either slow, 7+/- knots (my boat now) or fast, 15+ knots. The thought that plowing along burning lots of fuel at 8 or 9 knots as opposed to 7 knots is just lost on me. As with Art's Tollycraft, if you want to go faster and pay for the extra fuel, then should be able to cut half or more of the time to your destination. Just don't get doubling or more the fuel burn to add a knot or 2.

Ted
Hi Ted

Regarding our Tollycraft... a delightfully classic boat... in relation to what you mention, we basically have two cruise speeds.

1. 16 to 17 knots on full plane to get some place quick. That really works well when you have 130 +/- miles to cover on a short schedule for the day. At that speed my baby twins together consume 1 gal per nm (16/17 gal per hr. total). Hurrying along at that speed can cost some dinero; especially when prices are high! Our Tolly tri cabin is designed so at that speed people can hang-out in salon and chat in normal voice levels. On the flying bridge all you hear is the rush of water alongside her hull and the sweet resonance of exhaust with motors synced to rpm harmony. Oh yea, you also hear the occasional squawks of seagulls and get to watch seals and other sea life.

2. 6 to 7 knots which is bellow calced hull speed of 7.58 knots. With both engines loping along the motor sound is minimal, synced rpm harmony provides a really nice beat to enjoy, and she gets right at 2 nmpg. Not super-duper mileage… but acceptable (to us) considering other features and creature comforts our Tolly provides.

We also sometimes cruise on only one motor at 5 to 5.5 knots and get 2.75 +/- nmpg

Then there is always the “Big Blast” available of pushing both engines to over 4K rpm and speeding along at 21 to 22 knots. I’ve only needed to briefly utilize this WOT power/speed three times. Once on sea trial for timed minutes to make sure engines worked well and could take the gaff… if needed. Once for less than two minutes to escape away from a confeck-uration of idiot boaters gathered around the “The Maltese Falcon” entering SF Bay in 2009. And, once for way less than a minute during a close call with several boats where it was wise for me to substantively change course and position. Don’t ask what gallons per hour at that level of speed… cause I don’t need ta know and I don’t need ta care… just glad it’s there when needed or desired!

All and all, I pretty much baby every portion of our Tolly. She’s a gasser, but, she’s a good gasser – and – Comfortable/Fun as Hell! I believe with correct maintenance and thoughtful use she’s got many years of enjoyable service remaining.

Happy Boating Daze! - Art

Pict (by friends passing by) is me and grandson Cooper with buffer in his hand... 11/1/14.



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Old 01-19-2015, 12:04 PM   #40
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IMO the cost to the maker of somewhat larger engines is a small part of the cost of construction. For the reasons stated above they would not want to try to sell boats that could be considered under powered. More power appeals to most people. Fuel prices up to 1998 or so were less than $1 per gallon and people buying boats back then didn't have a political point to prove.
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