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Old 05-02-2014, 06:29 PM   #21
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I should add that in the Patent Application there was one humorous comment, although I am sure Schulz was not being funny. When discussing FD hulls, he noted the standard speed limit defined by waterline length and commented that adding power could not increase speed and that the hull, in his words, began to "sink" in the water, a reference I am sure to the notorious stern squat of FD hulls. But then he followed that by saying a FD hull would actually sink if driven too fast, it would drive itself right into its own hole in the water! I guess the moral for many of us is to beware overpowered FD boats!
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Old 05-02-2014, 07:09 PM   #22
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I think one of the things one can learn from the Shannon 46 article is that stuff we read in magazines is not always accurate. When I read technical or scientific information in magazines or news print where the publishing entity is not known for scientific accuracy and the material is something I know about it is amazing how off base the published statements can be. My best guess is that the people assigned to write the articles may know something about writing but little about what they are writing about. The fuel burn anomaly figures published in a boating magazine regarding the Shannon 46 should have set off alarms for any knowledgeable boating person involved with boat performance testing. There should have been an attempt to substantiate before publishing and if proven true this should have been a front page breakthrough article. I personally find much of the boat magazine boat test articles to be free advertising with a very rosy tint,and In our present business culture truth in advertising is what ever you can get away with.
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Old 05-03-2014, 12:28 AM   #23
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Originally Posted by THD View Post
I should add that in the Patent Application there was one humorous comment, although I am sure Schulz was not being funny. When discussing FD hulls, he noted the standard speed limit defined by waterline length and commented that adding power could not increase speed and that the hull, in his words, began to "sink" in the water, a reference I am sure to the notorious stern squat of FD hulls. But then he followed that by saying a FD hull would actually sink if driven too fast, it would drive itself right into its own hole in the water! I guess the moral for many of us is to beware overpowered FD boats!
Apparently back in the days when the large ships were all sail driven, there were a number of cases where they didn't reduce sail in time and literally sailed right under water.
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Old 05-03-2014, 01:06 AM   #24
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I should add that in the Patent Application there was one humorous comment, although I am sure Schulz was not being funny. When discussing FD hulls, he noted the standard speed limit defined by waterline length and commented that adding power could not increase speed and that the hull, in his words, began to "sink" in the water, a reference I am sure to the notorious stern squat of FD hulls. But then he followed that by saying a FD hull would actually sink if driven too fast, it would drive itself right into its own hole in the water!

I guess the moral for many of us is to beware overpowered FD boats!
And, the other moral of the story:

Own Really Well-Built / Well-Designed Planing Hull Boat!

Just Sayen!

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Old 05-03-2014, 11:28 AM   #25
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eyeshulman,

Post #22

Spot on!
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Old 05-07-2014, 07:15 AM   #26
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All the blither in the patent application was just to create a fog of difference in attempting to patent an old concept.

The Atkin folks used both reverse deadrise and box keels at the end of WWII.

These were published as plans in Rudder and Motor Boat in the 1950 era when folks might build a boat in their back yard.

The Seabright Skiff is known for efficiency (as well as being beachible) a gent named Rob White built an 18? ft version that got over 30mpg , at speed.

It was a version of the Rescue Minor .

The reverse deadrise does keep the boat level at slower speeds than pure plaining would.

Remember a boat really does not squat, it simply follows the water surface as it attempts to climb up and on top of its own bow wave.By pressurizing the stern to lift the boat stays level , so the boat begins to ride on the bow wave , and not climb it at a steep angle.

There is also some efficiency gained by the prop being parallel with the water , and recieving already accelerated water from the flow from the box keel aft.

The effect seems to peter out at over SL 2.6 or so and at SL 3 a genuine plaining hull is considered better.

With modern materials and todays light weight engines a more efficient cruiser that could go 12 --15K , burning 3 -6GPH GPH rather than 15GPH should not be hard to do. DL>100.

Perhaps tho the boat would have to be sold outfitted as the Huckins were , everything is aboard as sold , to prevent staggering weight increases by owners.

I looked into this as my first choice for a box boat , a cruiser to be shipped inside a Sealand container , at far less cost than actually motoring to the destination.

New England to down under , fly over , un box the boat and cruise away.

Yes the boat would be slender with about 7ft 6 in beam , but at 39 ft should be comfortable for a crew of 2 or 4 to explore new places ,even for months..

My concept is to have just the hull built , and install a used car engine to actually measure the performance.

If its crap, sell the hull to fish guys .

If works as well as Atkin claimed , the boat could go back in the box to have the interior and the rest installed.

The stability would be augmented with a center board style lowering , powered stabelizer.

Even cruising in the USA , where the USCG has given up the water to state and locals who install moorings in THEIR waters to rent , there is plenty of free space for a boat that doesnt mind a few hours aground during the visit.

The narrow hull would provide a superb seakindly ride , with a bow cockpit (Midnight Lace style ) the boat should be a very enjoyable cruiser.
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Old 05-07-2014, 09:18 AM   #27
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All the blither in the patent application was just to create a fog of difference in attempting to patent an old concept.

The Atkin folks used both reverse deadrise and box keels at the end of WWII.

These were published as plans in Rudder and Motor Boat in the 1950 era when folks might build a boat in their back yard.

The Seabright Skiff is known for efficiency (as well as being beachible) a gent named Rob White built an 18? ft version that got over 30mpg , at speed.

It was a version of the Rescue Minor .

The reverse deadrise does keep the boat level at slower speeds than pure plaining would.

Remember a boat really does not squat, it simply follows the water surface as it attempts to climb up and on top of its own bow wave.By pressurizing the stern to lift the boat stays level , so the boat begins to ride on the bow wave , and not climb it at a steep angle.

There is also some efficiency gained by the prop being parallel with the water , and recieving already accelerated water from the flow from the box keel aft.

The effect seems to peter out at over SL 2.6 or so and at SL 3 a genuine plaining hull is considered better.

With modern materials and todays light weight engines a more efficient cruiser that could go 12 --15K , burning 3 -6GPH GPH rather than 15GPH should not be hard to do. DL>100.

Perhaps tho the boat would have to be sold outfitted as the Huckins were , everything is aboard as sold , to prevent staggering weight increases by owners.

I looked into this as my first choice for a box boat , a cruiser to be shipped inside a Sealand container , at far less cost than actually motoring to the destination.

New England to down under , fly over , un box the boat and cruise away.

Yes the boat would be slender with about 7ft 6 in beam , but at 39 ft should be comfortable for a crew of 2 or 4 to explore new places ,even for months..

My concept is to have just the hull built , and install a used car engine to actually measure the performance.

If its crap, sell the hull to fish guys .

If works as well as Atkin claimed , the boat could go back in the box to have the interior and the rest installed.

The stability would be augmented with a center board style lowering , powered stabelizer.

Even cruising in the USA , where the USCG has given up the water to state and locals who install moorings in THEIR waters to rent , there is plenty of free space for a boat that doesnt mind a few hours aground during the visit.

The narrow hull would provide a superb seakindly ride , with a bow cockpit (Midnight Lace style ) the boat should be a very enjoyable cruiser.
Fred - I hope you do that.

Your depiction of boat size, design, material, and greatly reduced fuel burn interestes me VERY much. If as you conjecture: "With modern materials and todays light weight engines a more efficient cruiser that could go 12 --15K , burning 3 -6GPH GPH rather than 15GPH should not be hard to do." And, I say, if that ratio could be held true for the 39' loa x 7'6" beam boat you mention... well... I feel you would have designed/created a "sales winner" in the pleasure boating market.

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Old 05-07-2014, 10:18 AM   #28
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Art why did you need to quote that whole lengthy post? Seems totally unnecessary to me.

I think the lightness of the Atkins type box keel (actually called a "Seabright something") has more to do w it's perceived efficiency than the hull shape. The small prop and large wetted surface needs to be overcome w a feature that imparts a LARGE advantage in efficiency to overcome the small prop and large wetted surface.

Because of the fairly horizontal prop shaft and levelish running attitude some box keel designs may be more efficient that "some" other designs but I don't see it as a clear advantage to the type. Efficiency may not be an advantage of some heavier BK boats (for example those that resemble tugs) but the boat FF refers to (the Atkins River Belle I think) probably does have an efficiency advantage mostly because of her light weight and narrow beam.

I do like the River Belle and lots and lots of the Atkins designs. http://www.atkinboatplans.com/Cruisers/RiverBelle.html
I had a Sumner Craft boat that was a variation of the box keel concept. It was light also (composite) but had very soft chines and a rounded "box" kinda like a torpedo. A bit like a lobster boat powered by a torpedo bolted to the center of the bottom.

FF what is the status of your project or project to be. Sounds like it's still in the "to be considered" category. I thought about building "Tang" but I probably won't.
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Old 05-07-2014, 10:32 AM   #29
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Art why did you need to quote that whole lengthy post? Seems totally unnecessary to me.
GEEEE - Sooo Sorrrrry Eric. Any other posting instructions for me?

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Old 05-07-2014, 11:08 AM   #30
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Been waiting for somebody cool enough to jump on.

Thanks for being cool Art.
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Old 05-07-2014, 11:51 AM   #31
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Manyboats that was not a Sumner craft built on Long Island sound NY say back in the 60s?
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Old 05-07-2014, 02:40 PM   #32
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eyes,
Yes indeed ... Amitiville NY. Mine was a 29' express w a 120 Sabre. Loved the boat but we were moving to AK and she had to go. Life was complicated enough at that time .. and now to come to think of it.

I was worried about the sandwich construction as she was 40 years old at the time. And I was charmed by the Willard.

Amazing boat the Sumner Craft and only 8,000lbs (half that of the Willard) even w that heavy engine. She was sunk by exhaust water ingress and the Sabre engine was basically new purchased by the insurance company. I should have given her to a broker as I only got $5K.

The thing I loved about the SC is that she'd cruise at 12 knots w/o much power on and make 20 at WOT.
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Old 05-07-2014, 03:08 PM   #33
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Sounds like it's still in the "to be considered" category

Like all projects it takes big time and big money. Send money, and I can finish my 1 inch to the foot power test boat.

****

Some of the efficiency may come from the box keel creating a SWATH vessel, if most of the displacement is in the box.

It is also possible the bottom of the keel creates some water ski lift , which again would reduce wave making.

On one built version the builder complained of poor steering , after he about doubled the HP!

Atkin was Very unhappy the boat was modified , but simply recommended chine strips to stop the chine steering.

That should mean not much boat hull was touching the water.

While the Atkin reverse deadrise and box keel would be fine underwater ,

the profile would come from the master MR H. from a boat named STROLLER , my favorite.
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Old 05-07-2014, 05:27 PM   #34
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Regarding the efficiency of hydraulic drive, While living in Germany 2007-2010, I got to know the owner of a large yacht rental company (big business in Europe). To save the common breakage of drive-line components experienced with rentals, they went with a no-frills Nanni (Kabota) traditional 75 HP diesel mated to a Peachment (UK) hydraulic drives in modern, Polish built riverboat style hulls in 43 and 47 ft. if I recall correctly. The maintenance department was delighted with the life and reliability of this combo, especially since it nearly eliminated drive-line breakage, I rented one of these boats for a couple of weeks, and one could pull the throttle from full ahead, right through the gate to full reverse with no consequences, but this level of drive-line forgiveness has to come from the fluid component absorbing energy. According to the owner, that absorption rate resulted in an average of 15 to 17 more fuel spent over the rental period vs. the same engine and conventional tranny.
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Old 05-07-2014, 06:36 PM   #35
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... one could pull the throttle from full ahead, right through the gate to full reverse with no consequences, but this level of drive-line forgiveness has to come from the fluid component absorbing energy. According to the owner, that absorption rate resulted in an average of 15 to 17 more fuel spent over the rental period vs. the same engine and conventional tranny.
Guess it comes to: Pushing fluid costs fuel... water or otherwise!
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Old 05-07-2014, 06:39 PM   #36
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... the profile would come from the master MR H. from a boat named STROLLER , my favorite.


Damn - I love that boat! TY for posting pict...
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Old 05-07-2014, 11:59 PM   #37
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Hydraulic drive could be more efficient w short relatively straight large dia hoses or better yet pipes.

Stroller has a beautiful hull a little like eyshulman's boat but her house is lacking. Classic looking though. Not timeless.
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Old 05-08-2014, 06:31 AM   #38
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For a rental boat with high cost German labor rates Hyd drive would be ideal.

However for almost zero effort an old Twin Disc can be found with a SAE bell housing.

About $500 used and reverse is forever , so any direction prop can be used with any direction engine.

They are mechanical and HEAVY , but so efficient that no oil cooler is used and only 5 Quarts of lube oil (50wt) is required..

The ones from landing craft come with a warning !
, do not shift from fwd to reverse at full throttle TOO OFTEN
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Old 05-08-2014, 06:45 AM   #39
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I was pretty impressed watching the SRD performance videos. A new boat is something I have no interest in.
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Old 05-08-2014, 12:02 PM   #40
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Still no response from PMY on my critique of their test data. I made a point of stressing that fuel burn data on a boat that is marketed for its efficiency ought to receive extra scrutiny...both from the magazine staff and from the manufacturer. Last time I pinged them about something their reply was in the letter to editor section of next issue. If they do respond they will no doubt blame the calibration of the fuel flow instrumentation. We'll see. They'll probably cancel my free subscription...
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