Custom newbuilds, on the cheap?

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FF

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Posted this to the designers forum , to see what reaction they would have.

Perhaps ypu would care to comment,

New GRP boatbuilding method?
<hr style="color:#d1d1e1;" size="1" />Years ago we built one off cruising/passenger boats with the "Franz Mass" method.
A male plug , covered with AIREX , a hand laid outer skin , remove the plug and lay up an inner skin.
Was fine , even for USCG sub T boats for carrying passengers , but OH ! what a labor intensive building method!

I observe the modern method of creating a production mold plug by carving it out of a hunk of foam and am indeed impressed with what a 3 axis cutter can do.

I wonder with modern computer files and all the resin advances if a on off could be directly built.

LLoyds GRP is based on an all chopper boat ,and many solid glass boats are 40+ years old and still going strong.

My proposal would be for a lay up head for that 3 axis machine ,that would lay down (say, GRP rope for example) a layer that is 1/2 or 3/8 inch thick , starting on the shop floor.A chopper head with movable side rails for hull thickness could also work.

The unit would simply lay fast hardening "rope" that was infused with resin and hardener.

The outer shell could simply be built on itself , the "rope" having hardened as the layup head installs it.
If added thickness were required the second and other passes should have no secondary bonding problems as it would be so quickly done.

I have seen articles on NZ boatbuilders that could computer cut a ply interior that locked together (egg crate) and in some cases were even pre-finished , before being dropped in the hull.

Perhaps the rope boat builder could create outside a pre made interior , so there would be a relatively ready to finish boat on completion of the hull forming.

The exterior might require sanding and filling , in the old way , but with some of the newer spray fairing compounds , and yet a different head (for surface finishing) could be installed on the 3 axis machine.


Interesting concept , a crew would assemble the interior , start the machine and simply watch as a hull is created.

Except for the computer guy the labor could be low skilled.

A good quality paint (allgrip?) would finish the hull.

The disadvantage is very light weight construction would be hard to do, but for a large number of cruisers hull weight is not that much of a disadvantage .

There would be almost ZERO waste , and the air pollution requirements should be easier to meet .

Anyone think this would work?
Anyonehave* a spare 3 axis machine and a yen to innovate?

If it works , almost any boat could be custom built as desired , no more COOKIES!*
biggrin.gif


FF


-- Edited by FF at 07:46, 2008-09-21
 
Three axis, pre-preg tape laying machines have been used for many years in the aircraft industry,

Yes on to a form or into a mold, this would require neither.

FF
 
FF and Slow, If it's going to be " cheap " or " economical " the semi displacement hull burns far too much fuel if one has even medium range aspirations. To build " cheap " Ive got another ieda. Here on Prince of Wales Island Yellow Cedar is so availible the Forest Service makes boardwalks out of the stuff. Iv'e had thoughts of building a large open skiff/launch/dory just for fun. How much does it cost to build a wood boat in the lower 48 compared to other methods and materials? I think polyester resin comes from crude oil .. does'nt it ? Should be quite expensive by now. In the book Voyaging Under Power ( Beebe ) a one off boat ( Mona Mona ) was built very cheaply useing FG sheets and frames. The boat was very successful. Is this old technology that would be stupid to consider now? The tools and materials to build Mona Mona were all very common and inexpensive. Sounds like the form cutting tool in your method FF would be unavailible at Sears.

Eric Henning
Willard 30
Thorne Bay AK
 
Hiya,
** Mr. Willy.* I don't think the cost of materials is as signifigant a factor as expertise.* Many moons ago when wood was the only material besides steel to build a boat, shipwrights were common (marine-wise).
* Now, to lay up a hull in fibreglass, all one has to do is get a mold, a couple of people to supervise and then let loose a crew with chopper guns.*
* I applaud you for wanting to build in wood.* I had a wooden boat for 12 years and did a lot of the repairs myself because, for the life of me, I couldn't find anyone that did good work.* I saw one "shipwright" fastening 5/8" planks onto 3/4" battens using 2" screws and this guy had a very good reputation and was in high demand!
** Nothing IMHO "rides" like a wooden boat or "talks to you" like a wooden boat.
** I don't know anything about yellow cedar or it's suitablility for boat use, but, I would say, go for it.
** How "large" are you planning to build?
 
"a new generation of semi-displacement hulls. I guess it depends on your definition of cruising....there's coastal cruising and blue water cruising."

I prefer to call it Cruising ( brown water) or Voyaging (blue water)

By the way, the power required for a semi-displacement boat at hull speed is very close to that of a full displacement hull. New semi-displacement designs will optimize that low speed end while retaining a very slow semi-planing capability with one relatively small engine."

But not yet,

There has been loads of tank work in the dream of cheap plaining.

So far no boats have been built , although there are some good results from drag tests , but nothing a break thru.

The biggest hassle with a "fast" cruising disp boat (semi disp or whatever name you want) is the poor hull shapes cost 10 or 15% in mileage at disp speeds , and having a large enough engine to semi plane is to have a grossly oversized engine with lousey efficiency when in disp mode. An old LST tranny with a big engine and a small disp enginecould solve that half of the problem.

Our "new" design ( the boxable boat) attempts to overcome these problems with a better hull shape for modest cruise (SL 3 and below) and big buck tech to overcome the engine problems, a 2 speed transmission (ZF) and CPP (Hundstat) .

The boat will not have a large market as the volume required by most marine motorists is far above what a 39 ft boat with 7ft 6 inch beam will supply.EX ragbaggers will be happy tho.

A couple that wants world wide cruising (via a container ship delivery) in a boat that will only sleep 4 is not in high demand. Beachable is of interest to many tho.

But I want one so that's enough to continue the project.

I will probably have the boat built in NZ with the D. Kelsall method , in foam core , and finished inside to work boat specs.
The EU will require under 8800lbs so teak, marble , and all the usual unobtanium and interior forest of endangered species of trees is out. Formica on foam is in.

To me folks will happily give up burst speeds in most cruisers as 1 nm / gal is too painfull.


A good example is in this months PMM.
Some old disp Willard with a newish engine can cruise at 7.5K at 1.3 gph.

The over engined Grand Banks (800hp total installed) gets 8.3 at over 5gph !

Sure the Banks will wallow up to 12 or 15 K , at a coat of 2GPM !

30+ GPH is Probably fine for some , but paying 300% more at normal cruise 8K , every cruise , every day will probably limit the market to the same doctors that kill themselves with regularity in twin engine air craft.

But the Banks interior IS nice.

FF
 
My semi-displacement 36' Marine Trader Sedan burns 1.6 gallons at 6.4 knots, how much better are you hoping to get with a full displacement? Oh and we don't roll like a pig in mud either.
 
RT, Haven't shared with you in a long time. I've read many of your posts though and when I see one I dive right in and read because you frequently have great things to say. Yellow Cedar is one of the best woods for planking in the world and it's one of those woods that also will hold fasteners fairly well so one can build the entire boat out of the stuff. YC gives off a strong odor when freshly cut that is absolutely wonderful. About 30' is what I had in mind but the big problem is where to build it. I have a nice large house but no other structures .. yet. Many other projects are way ahead also .. including car/boat ports ect.
Daddy, consider the following boats at 6.4 knots.
Krogen 42, 19 tons, 17 hp
Willard 40, 16.5 tons, 17 hp
Neville 39, 20 tons, 21 hp
OR consider this. You are maintaining about 32 hp. A Willard 40 with that much power applied will be making well over 7 knots. But the worst thing your'e doing is only useing 32 hp with a 120 hp engine .. thats extreem under loading.

Eric Henning
Willard 30
Thorne Bay AK
 
". Comparing an old 800 HP twin Grand Banks that has a drive train optimized for 20+ knots to ANY displacement hull is pure nonsense


True , But,,

The GB pumped in PMM is BRAND NEW! New design , new engines , new construction method.

Has Zeus drives (that claim 30% better efficiency ) new style Scrimp construction for light weight , and electronic controlled injection (another claims 10% better).

It is "state of the art" a boat built JUST for the semiplaining regime the Banks folks think is great.

The old Willard is as low tech as was done decades ago, BUT with a more rational hull style and far ,far more rational engine choice.
Drive train is a prop and shaft , 120 years of understanding.


The engineering on the Banks is probably not the handycap, the ADD Dept. boys that thought 800+ hp could be uses in a cruiser is probably the source of the pittyfull performance.

Banks are claimed to be semi custom , so perhaps 2- 100hp Deere conversions could be substituted , but the boat would still be handicapped by the "semi Displacement " HULL, and would still suffer the poor ride and high drag of such a hull at disp speeds.

The most probable reason for the use of pod drives is to lower the skillset needed to operate the boat , esp docking, or coming alongside.

FF
 
"Oh and we don't roll like a pig in mud either."


The only way a hard chined boat obtains added stability is to run at speeds that produce dynamic lift , those semi displacement speeds. SL 1.5 and higher.

When operated as a DISPLACEMENT boat at disp speeds the ride , roll , and handeling will resemble any plaining boat at low speed , poor to miserable

By getting up a K or 2 faster , some dynamic lift is created , and the boat may be able to "run for home" smoother than the disp hull.

BUT the cost for this exercise is 3X to 7X higher fuel flow , so this "safety " feature is an exercise in Defueling.

As always you pay your money for your choices.

FF
 
Sorry guys but I can't let this one go!

The new Grand Banks 41 with Zeus drives is a real winner! Believe it or not, there are those of us that simply love the classic looks of Grand Banks but would like a little more speed to offset tides, currents, etc. This Europa model is what I (and many more) have dreamed about having. All the classic good looks of GB Europas but with some mid teen speed and joy stick handling. I have been pestering my broker as to when he will have the first one and I'm told it will be a few more months.

Although I think the economy of the 6 Knot trawler is truly remarkable, I don't want to sit at anchor in the Great PNW, waiting for slack tide and a current going my way.

I would really appreciate Marin's opinion of the GB 41 as he is a dyed in the wool GB guy who lives in God's country.

Walt

-- Edited by SeaHorse II at 11:10, 2008-09-24
 
The GB41 is way out of my boating budget constraints so I can't say I'm eagerly awaiting their arrival in this area. But I think the concept is terrific.

Two of the most powerful tugs in the world are stationed in Bellingham Bay down the road from our marina. They are here to assist the tankers and bulk carriers moving to and from the refineries and aluminum plant in the islands. They can pull equally hard going forward, backward, or sideways and they can maintain a stationary position without yawing in just about any weather. Watching these boats maneuver in strong currents and rough water is impressive to say the least. To have this capability in a boat like the GB41 would be wonderful.

Taking operating costs out of the equation I agree with Walt that having the abiity to power through the passes when the currents are starting to kick up would be great. And for people who have time limitations on their boating schedules, the notion of being able to get to and from somewhere fast in order to enjoy as much time as possible at that somewhere is a big bonus.

We tend to pooh-pooh the high fuel consumption and "inefficiency" of so-called fast trawlers, Eastbays, etc., but the fact is that speed has definite advantages. If it didn't we all wouldn't still be driving 70 and 80 on the freeways when 55 saves an impressive amount of fuel. Just because I have to run at 8 knots to maximize the benefit of my boating budget (and the life of our 35 year-old, 120hp engines) doesn't mean that the "go faster" concept is invalid.

It's all well and good to turn up one's nose at bow and stern thrusters, two or more engines, computer-assisted remote vessel control, and so forth. I'm guilty of doing this myself from time to time. But the fact remains that given the choice between being shoved into another vessel by an adverse wind or current or pushing a few buttons and having the boat stay clear of danger, I'll take the buttons every time over the potential expense of fixing my boat and maybe someone else's too.

It's popular to say, "Well, look at commercial fishing boats. One engine, no thrusters, and these guys can dock anywhere under any conditions." True enough. But look at their boats. Heavy, heavy wood on the older ones, steel or aluminum on the newer ones, and preserving that "yacht 'look is not high on their priority list. I've watched a lot of commercial fish boats and local tugs come into docks all over this area. They're very good at it, but they don't worry about the paint. They come in fast and mash them against the dock and get a couple of lines out.

So I think what GB is doing is brilliant. The technology is there to allow you to have a computer manipulate Z-drives in such a way that the boat will remain motionless regardless of wind or current (up to a point) so why not take advantage of it? I can think of a lot of times I would have benefited from such a system. So I may pooh-pooh it from time to time but it will be because I can't afford it, not because I think it's a dumb idea
smile.gif
 
nomadwilly wrote:


Daddy, consider the following boats at 6.4 knots.
Krogen 42, 19 tons, 17 hp
Willard 40, 16.5 tons, 17 hp
Neville 39, 20 tons, 21 hp
OR consider this. You are maintaining about 32 hp. A Willard 40 with that much power applied will be making well over 7 knots. But the worst thing your'e doing is only useing 32 hp with a 120 hp engine .. thats extreem under loading.

Eric Henning
Willard 30
Thorne Bay AK
Your not taking into account the longer waterline of those boats. I'm also turning a cruising prop and am loading the engine just fine, but yes if I was to repower I would put in a smaller engine. My boat has a 2.5/1 ratio turning a 24x22 4 blade wheel.
*


-- Edited by Daddyo at 14:51, 2008-09-24
 
There are those that will "stone me" for what I'm about to say.

I have been messing about in boats for about 55 years. All kinds of boats! Big ones, little ones, sailboats, go fast, go slow, etc., and at my present station in life, saving fuel is not the biggest thing on my mind! I want comfort, looks, a fair turn of speed, easy handling, two staterooms, full walk around, decent tender storage with easy launch and recovery, some teak (yes, I like teak trim) a great cockpit, single or twin (I really don't care) and all that at under 42 feet!

I've been waiting for such a boat for a very long time and the folks at Grand Banks have come up with it. Oh, I agree that there are other boats out there that have most all the attributes I've mentioned. The missing attribute, however, that is not negotiable is the LOOK. Not to mention fit & finish.

I attended the Newport boat show 2 weeks ago with a good friend who is looking to sell his express and buy something "more comfortable." We looked at about 50 boats that day and both of us said the 47 GB Europa was our favorite. A little bigger than either of us want, which means I'm taking a hard look at the GB 41Z.

I have never owned a Grand banks....always wanted one.....I think it's a lock!

Walt (let the stones fly!)
 
Walt,

You won't get stoned by me. I saw the same boats you did, and I agree with you.
 
sloboat wrote:

GB might have had it right when fuel was $2 a gallon. Now I think they're trapped with their jaunty speed boat. *We shall soon see.
Someone on this or another forum pointed out awhile back that fuel costs, even at today's and tomorrow's prices, are but a very small percentage of the overall cost of buying and owning a boat.* Given the worldwide market for boats like the GB41, I suspect they will have no problems selling them as long as they meet their potential buyers' requirements for quality, comfort, amenities, handling, speed, efficiency (given their power and speed) and so on.* I don't believe today's boatbuilders operate in a vacuum--- they do extensive and continuous market research and analysis.* The Nordic Tug folks would not have come out with a 52-footer (or whatever it is) if they weren't more than reasonably sure they'd make a profit on it.

That doesn't mean they get it right every time and as Sloboat said the jury's still out on the new GB models.* But my guess is that baring some global economical catastrophe GB's lineup will make the company a nice profit.
 
Daddyo, WLL means next to nothing if you don't have a displacement stern that allows the water to gracefully and smoothly rise to the surface. If wour'e at the right speed/length ratio the boat does a bit of surfing, adding to efficency. The point stands. If you have a proper displacement hull a lot bigger boat than yours can be run at your speed with less than half the fuel burn. A semi-displacement hull wallows along like a pig in mud at disp. speeds, dragging her stern along turning the water into a washing machine froth. The wake of a displacement boat is a thing of beauty and grace, not to mention efficency. And of course the more your stern looks like your bow the better the boat handles in following seas. Short wide boats are the worst. However if I could afford the fuel I'd have a planing boat.

Eric Henning
Willard 30
Thorne Bay AK,
 
sloboat wrote:

The notion that fuel is a small part of boat ownership is history.
The sales of new and new-ish boats is thumping along quite nicely in our marina.* However all the boats being bought are big and expensive.* The Port of Bellingham is moving ahead with it's new marina basin project to occupy the former settling ponds of the torn-down Georgia Pacific paper mill.* All the slips in this 500-boat basin will be 50 feet and larger and a number of them are already spoken for even though the basin is several years away from being opened.*

What's dropped off* sharply are the sales of used boats and new "smaller" boats like Bayliners and the like.* But the trade in newer GBs is quite brisk in our marina, and there have been a number of large, brand new boats, sail and power, that have appeared in the marina over the last few months.* I see a number of brand new mega-yachts being rolled out and delivered at Delta Marina, down the road from my office in south Seattle.* To the folks buying these kinds of boats, the cost of fuel IS a small fraction of boat ownership.

And this is just in the US.* In Russia and the middle east the demand for luxury boats (and business jets) is skyrocketing.

*
 
Those of you interested in the GB might also take a look at this: http://www.nwtrawlers.com/index.php?s=NW45

They're American made, right up there in Anacortes, WA... and they're semi-displacement. I've been on 2 of the 45s, and crawled around the fresh-out-of-the-mold 50, and they're nice boats!
 
I guess I'm not thinking of this correctly because the cost of fuel for me is a small part of the equation too. Here's my thought process.

I burn 1.9 GPH at 1750 RPM with my 120 Lehman. Let's round that to 2.0 GPH. I currently run the engine about 200 hours per year. In 2 more years I will retire and double that. But let's stay with the current. 2 GPH, 200 hours equals 400 gallons of fuel per year. 400 gallons of fuel at $5.00 per gallon (higher than current prices but it makes the math easy) equals $2,000.00 of fuel per year.

I pay the lowest moorage rate in Puget Sound, save someone who has a private deal somewhere. My moorage is about $320.00 per Quarter, about $110. per month. That's $1400.00 per year for moorage if you add some extra electircity in the wintertime. (yacht club and we own our own tidelands lease)

If I was mooring in a public type marina I would pay at least $350.00 per month for covered moorage. $350 times 12 months is $4,200.00, more than twice my fuel bill each year.

When I'm out cruising, because I track it as part of retirement planning, I know I spend 1/3 of my time in a marina, 1/3 of my time at reciprocal moorage and 1/3 of my time on the hook. The hook is free, reciprocal is 3-4 dollars per night for electricity, and commercial averages $55.00 per night. (40 foot) I am out 6 weeks per year, so I spend about $825. on cruising moorage.

Mainenance is a moving target because each year can be different. And since this boat is relatively new to me, 2 years, I don't have a perfect number. But, with 15 years of experience with my last boat, $150.00 per month is pretty close. I do all my own work including the bottom and engine repairs. 12 months worth of maintenance is $1800.

Now that's just the tip of the iceberg for some who have a boat payment to make, live in an area where moorage is more expensive, cannot do their own repairs, etc. The "other" parts of boating cost me about $4000 per year. Fuel is only 1/3 of the cost of boating. All told I'm spending $6000 per year boating. (not including the initial investment in the boat or depreciation on that investment)

My wife wants to take an African Safari. An 18 day trip is $6195 per person. The boat is looking cheaper and cheaper even if diesel goes to $10.00 a gallon.

Ken
 
Your 200 annual hours might be cut to only 100 with speed, but think of the equation at 30gph for those 100 hours.

FF
 
Fuel might be the straw that broke the camels back. I'm guessing if a freak storm sank a bunch of boats and insurance rates skyrocketed then people would be sitting at the dock too. The same as if guest moorage prices doubled.

In my view, what you see is people living too close to the edge. If you don't have an extra $100.00 per month, (the effect of the price of fuel doubling, in my circumstance) to keep boating, then maybe you have too much boat, too convenient of a moorage spot, or some other problem.

My moorage is not the closest I could find to my house, it's the best trade off of convenience and cost. My boat is what I could afford to pay cash for. By saving my money after paying off the smaller older boat, I could pay cash for the newer bigger one.

And I don't appologize for having whatever money I have. While I was working the 70 and 80 hour workweeks others were enjoying their time off. Now I'm ramping down to 50 and 60 hour weeks. When others went out to fancy dinners we cooked at home. If you want to call me wealthy go right ahead, I earned every penny.

And those who buy the new GB 41 probably earned it also. And if they didn't, if they are trust fund babies or ripoff artists, it won't do me any good to be jealous. There's nothing to envy about my life or theirs. We all make a large portion of our luck. And the portion we can't control builds character.

As always, your views may vary,

Ken
 
FF wrote:

"Oh and we don't roll like a pig in mud either."


The only way a hard chined boat obtains added stability is to run at speeds that produce dynamic lift , those semi displacement speeds. SL 1.5 and higher.

When operated as a DISPLACEMENT boat at disp speeds the ride , roll , and handeling will resemble any plaining boat at low speed , poor to miserable
I completely disagree here.* A semi or planing hull has more "initial stability" than a full displacement boat with potentially rounded bilges(think static versus dynamic stability as it relates to planes).* A hard chined square assed boat is going to resist roll due to its added buoyancy spread out over its beam.* Whereas a full displacement boat will not intiallly resist roll.* This is THE reason boat manufacturers design semi-planing boats and then power it to do displacement speeds.* The obvious downside to this and maybe what Fred was getting at is that once you do get into rolly conditions, a square assed boat is going to "snap" back and forth due to that added buoyancy whereas a rounded bilge boat will have a more gentle predictable rhythmic*motion.
 
John Baker, Very good sir. As to manufacturers square assed hard chine boats you may have a point. In recent years boaters have been binging on stability. People have gone nuts for boats that boast stability. Catamarans, rib's, hard chines, stabilizers and just plain wide fat boats are more popular than ever. In the 20s, 30s, 40s, and fifties boats were narrow because we did'nt have much power and narrow boats were much more efficent. WE ARE GOING BACK THERE... because we can't afford the power. How readidly people can kick the addiction of excess stability will determine how fast we get there.

Eric Henning
Willard 30
Thorne Bay AK
 
No reason you can't do a narrow boat wth stabilizers. The corporate yacht I was associated with for awhile was like this. Designed by Philip Rodes (sp?) and built by Abbeking & Rasmussen in Germany in 1966, she's 120 feet long but relatively narrow (don't remember the exact beam). She was fitted with one of the first retractable active stabilizer systems, and while she really needs them out in open water, they do a good job of providing a smooth, stable ride. And modern stabilizer systems are even better, more responsive and more reliable.

-- Edited by Marin at 14:52, 2008-09-26
 
sloboat wrote:


*Anybody want to discuss the best dock condo?

-- Edited by sloboat at 19:15, 2008-09-26
Start a new thread.* But since you liked the Hatteras LRC, why not the planing 53 foot Hatteras.* I think they are damn good looking boats(better looking than the 58LRC IMO) and they have some speed on them if you need it.* Talk about a fantastic layout as well.* All of the above features are why they still command good money.** And they made lots of them as opposed to the LRC so it*should be easier to find a decent example.
 
But since you liked the Hatteras LRC, why not the planing 53 foot Hatteras.

As noted if folks are willing to get off the PC "trawler" verbage there are some fine cheap boats out there for cruising.

FF
 
For those that are serious about economy or " cheap " as FF says may want to consider this idea. There are lots of old boats, nice big Tollys, Carvers, Chris Crafts and many others that mostly have twin 8 cyl gas engines and are on the market cheap and getting cheaper fast. One could buy one of these, modify the shape of the stern and repower with two 30 or 40 hp diesels or perhaps one 60 to 70 hp. This should be relatively low tech work in either wood or fiberglass. A great deal of flotation at the stern would be removed so fore and aft trim should be considered. When I was shopping for my Willard I had a bit of an affair ( in my head ) over the GB 32 but considered it much too inefficent at disp speeds. Thats where I got this Idea. A Yanmar 4JH4E ( 55 hp ) would do just fine. That could even be a bit over powered. To make the mod job as easy as possible one should select a hull that has straight lines from the center of the bottom out to the chine so the original hull bottom can most easily be bent in a nice fair curve up to the water line. Some of the hull on the lower aft sides below the water line and most or all of the transom below the water line would be removed. One could get a very inexpensive to an incredibly inexpensive mid sized to large Trawler. This could be done to a Nordic Tug. I wouldn't be supprised if Nordic ( or others ) came out with such a boat to address the need for more efficent boats. As it is now anybody that can afford to buy one can pay for the fuel but as the boat gets older there comes a time when thats not true. Personally I like hard chine boats and they are only a tad less efficent than smooth chined boats. I think this would be a great project for a great boat at a great price.

Eric Henning
Willard 30
Thorne Bay AK

-- Edited by nomadwilly at 18:59, 2008-09-27
 
Hell, ya'll could just buy mine (so I can get out from under my note and buy that shiny new trawler I have my eye on).

Semi-seriously, my boat is the epitome of the floating condo. Nice cockpit, sundeck, flush main deck (1 6" step from saloon to galley/PH level), and decent living quarters below decks. Large FB and boatdeck, with davit and new bimini/strataglass... and we're fully stabilized and have a bow thruster.

At 1200 RPM, the fuel hungry 8V92s burn around 17 gph and we're cruising at about 10.5 kts. Back it down to 1100 RPM, we're burning around 10-12 gph and cruising at about 9.5 kts. Where it gets hairy is when it comes time to blow out the DDs. WOT is around 2k RPM, we're burning 76 gph and cruising at around 20 kts
eyepopping.gif
* Suffice it to say we only blow them out when necessary.

Make me an offer I can't refuse.
 
" A semi or planing hull has more "initial stability" than a full displacement boat with potentially rounded bilges(think static versus dynamic stability as it relates to planes). "

Hulls with great areas of flat sections aft DO have more initial stability which is very comforting for lubbers stepping aboard at the DOCK,

Unfortunatly ,The large flats work as levers that increase the roll action any time the vessel is not gaining stability from being on the plane.

At disp. speeds the rolling and heeling angles will be HIGHER than the disp. boat that does roll, bur also HEAVES , lifts as the wave passes., to absorb the passing energy.

That's why there are very few flat bottomed or V bottomed boats Voyaging.

FF
 
"The heaving is mostly done by the spouses on board."

Guess you have a plaining boat , the bride only heaved once on the loop , after a rather rough crossing of Lake Ontario.
Thin water , big fetch , even bilge keels didn't keep breakfast for her.

Got some small flopper stoppers , with poles from RY , but still on the to do list.

FF
 

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