Thanks to the efforts of a few dedicated lovers of wooden boats, we currently have a master boat builder who can produce an heirloom quality yacht more affordably than the fiberglass counterpart.
Remember the hull is a small part of the total cost, but a big part of keeping the water where it belongs (on the outside).
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals.
Trim Tabs on a well designed hull allow the hull to run at its optimum running attitude over a broader range of speed, sea conditions and weight distribution. For example if the boat can plane at lower speed and still keep its bow down cutting an oncoming chop it is essentially running on its lines and the good characteristics of its hull design are working. Calling Trim tabs a crutch for bad design (if it is a good design to begin with) is like faulting an aircraft designer for including flaps for low airspeed performance. I think what we have here is an engineer who is accustomed to having an extra 25% runout of any adjustment beyond what should be needed.
I'm not sure what 'philSweet' is getting at but I would state its obvious that you need no more trim than that required at WOT.
Location: united states A boat that requires drives to be fully tucked in at WOT and interceptors down at WOT is unusual.
Can you describe in more detail what happens if the drives are not fully tucked in and if the interceptors are not mostly down approaching WOT?
Location: Australia Worth trying bigger, wider tabs as an experiment, doesn't necessarily create more drag either. Originally Posted by Mr Efficiency Worth trying bigger, wider tabs as an experiment, doesn't necessarily create more drag either.
Originally Posted by tunnels How can more surface area in the water not create more drag ? Originally Posted by tunnels What is the better trim tab and wide one across the boat ??
I've uploaded several pics of a very successful one of the French Navy, a bit too big, but a good example of the results obtained when a boat is designed for efficiency and not fashion.
The boat is very heavily built (Lloyds A100) as shows its displacement of 41 metric tons full loaded.
Please, do not post information little by little about your design determining factors, or I'll not be happy about helping (And probably others either).
As more and more fishing effort to be diverted to areas beyond traditional fishing limits, the expertise available with the Project has to be deployed to conduct intensive fishing operations in grounds where sizeable resource potential is indicated through exploratory surveys by vessels of Fishery Survey of India. Location: india Can anyone help me with the basic fundamentals of Ship Hull Detail Design? The Societys premier reference work, a revision of the 1967 publication on naval architecture covering ship's geometry, stability, flooding, strength, resistance and propulsion, vibration, ship controllability and motion in waves. Being a Naval Architecture Student you shoud be able find answers to all these questions by yourself from basics you have learnt over last 6-7 semesters.
To create space to locate a big diameter propeller, if I understood your question correctly. If you use a rudder, you usually use skegs to support it with this type of vessels, if I properly understood your question. Fiberglass Boat Designs CAROLINA HULL Web site design by D4 Data Design Platt Design Garvey 21 fiberglass hull shown running with a 40 hp outboard.
Southport Boats manufactures fiberglass fishing boats using an exclusive Hunt 4 hull design in Augusta, Maine. Fiberglass can be contoured to any desirable shape, resulting in more efficient hull designs.
For a one-off fiberglass hull, this process is even harder because the relatively soft Forming in Fiberglass was added to the Boat Design To be sure that the modified boat hull won’t leak at the day until your hull and internal surface of the boat are covered with enough fiberglass to meet your design HydroMarine of Germany Fiberglass Race Boats in white gel coat unless specified otherwise. Richard (Apex1) is no longer on the forum and has undergone some substantial personal issues, just before and considerably since leaving the forum. You'll find a lot of threads and projects start with good intentions, but life and other things tend to get in the way. As to your other questions and references to the photos - well without them, it's tough to comment. I have reposted my original thread using the attachments buton on the interface to post the original pictures. Location: Eustis, FL It's difficult to tell what you've shown there, but it appears to be several different types of designs, though with some similarities. These designs typically don't fully plane off, though if over powered they can reach semi plane speeds. A vessel is nothing but a bunch of opinions and compromises held together by the faith of the builders and engineers that they did it correctly. Originally Posted by PAR It's difficult to tell what you've shown there, but it appears to be several different types of designs, though with some similarities.
The more time I spend here, the fonder I grow of the people in the village in general and even more so of my students, specially the boys whom I?m teaching to sail. I?ve spent a lot of time trying to find a way to help these boys and the people in general, besides just classes and lessons.
4.And who knows in 20 or 30 years gas might be so scarce that there is a general return to sail or motor sailing for fishermen. Using only the existing tourism infrastructure I see how to generate jobs for these boys using intelligent and ecological hull and propulsion design.
So, wouldn?t it make both economic and ecological sense to use a lighter, more efficient, displacement hull with electric propulsion for tourism and transport? With short distances of 1-8 km for most tours, and an efficient and light hull, wouldn?t an electric inboard (say 500-1500 watts) and a small battery bank and maybe 20 sq. Above you saw the pictures of the pangas with a tarp for shade, taking tourist across the estuary. And to make the project less costly to start, why not a trolling motor instead of a more expensive custom electric inboard installation. I read that minkota has developed trolling motors that use variable frequency modulation, or electric pulses, like modern electric cars, to control motor speed.
What about this with a custom solar panel roof and 4kw inboard motor and keel designed to hold a long row of AGM Batteries? It is very sad to see how badly one-party systems did the people, and just as bad to see that beginning in America. El_Guero Previous Member   PS for tourism, you might check out some of the designers on the board who design catamarans - a more stable platform is always better for tourists. Location: finland Tropical sailor - the PWM (pulse width modualtion) controllers have been put to all kinds of cheap trolling motors.
Originally Posted by El_Guero PS for tourism, you might check out some of the designers on the board who design catamarans - a more stable platform is always better for tourists.
Location: West Palm Beach, FL reply Being small and Corten steel JULIA seemed to have the scantlings of a miniature ship. Location: new jersey Forgive my ignorance, but can you explain the auxiliary rudder, exactly what it is and how it helps you not have to trim the rig as much?
Location: USA Here's a nice video from mid-Atlantic with a junk rig going to windward. Location: Brisbane Here is a website which tells the story of a young Aussie couple sailing there 29 foot junk rigged boat from Canada to Australia via the northwest passage.


Location: Michigan, USA I've thought of a different approach to a Chinese lug.
There are only two 'boomlets' and a yard, so the number of reef positions is reduced to just two. Another advantage is there will be no more worrying about the sail chafing against the mast. I made a sail very different from the one shown, but designed to work on the same principle, when I was a teenager. It went to windward in a surprising fashion, once beating a boat nearly the same size, with and nearly the same sail area and load, up wind.
When tying a reef, one has to be very careful to make sure the 'gill' keeps its pitch in relation to the sail behind the mast.
In earlier drawings, I had the yard nearly parallel to the boom with two battens at each reef point, one for the 'gill' and one for the sail behind the mast.
After more reading about traditional rigs, I became convinced the forward sloping yard was the way to go (to increase tension on the luff and to shorten its length, making it less likely to sag). Location: Long Beach, Indiana I've been looking at junk rigs for some time, for me the merits of easier sail handling, unstayed mast, and simplicity outweigh the slight drawback of not pointing so high. Originally Posted by pcfithian I've been looking at junk rigs for some time, for me the merits of easier sail handling, unstayed mast, and simplicity outweigh the slight drawback of not pointing so high. Good thing if you're designing a packaging machine, but hydro doesn't really degrade over time the way machines do (I haven't seen gravity break yet).
But do you run your boat at maximum negative sterndrive and tab trim to optimise WOT and still not achieve a good pitch angle for maximum speed? Your comment about critising aircraft design is wrong as that's exactly what flaps are for, to improve low speed performance(like a boat) and your comment overlooks the fact that planes don't usually use flaps to correct wing profile at WOT maximum speed for a light load.
My comment are about a boat designed very recently by a well known designer with an International boat builder. The question would be 1)has it got enough at WOT and 2) Is it achieved with a satisfactory balance of organic inbuilt hull trim as opposed to external devices.
As you can see, there is nothing fancy but just optimization born from years of experience at sea. Bulbous bow for long rangers, but as you are talking about a 1 day trip , you really don't need it. Pascoe, Marine subjected to the same type of forces as a boat hull Instead, modern fiberglass boat hulls relay on a The boat hull design is one of the most important considerations when choosing a boat. A thorough review is given to the characteristics of fiberglass materials and laminate design 8m Fiberglass boat with cabin, New Zealand Design Engineering, Deep-V Hull, CE, 5-year fiberglass Warranty, Volvo Penta. This hull design is are currently set by Lloyds and American Bureau of Ships for fiberglass boats. This type of fishing boat has all but been replaced here in Mexico with the modern panga style and 40hp Yamaha. The interface for posting on this site detects my mexican IP and tries to correct my spelling based on Spanish instead of English. You can include images inline using IMG tags from sites such as flickr, but what is inside IMG tags has to be the url of the actual jpg image, not an html page. They look to be traditional working craft, but as to specifics, well the photos just don't provide enough information. What I didn?t explain is that I?m a volunteer teacher at the community center in a small fishing village. Most of these boys are sons of fishermen and many have already started going out to fish with their fathers or others. There already exists an industry for tourism and eco-tourism in the area, but it could be developed so much more and in a sustainable way. The panga from 25? ? 33? with 40hp Yamaha is the standard fishing boat here as I already mentioned, but it also serves as the only transport for tourists who want to get from the towns on the mainland, across the estuary to the island beaches in front of them. One of the websites says that their 30? panga weighs 5500 pounds with a load capacity of 8000 pounds. Maybe even one made with stitch and glue or ply over frame construction that can be done by the locals themselves, without need of government subsidy or political association. At max speed the resistor based speed control gives all the juice to the motor - this will mean equal efficiency to more modern speed controller. Other than GINGER you're the first person I've read about with a small Witch so I'd be interested in your comments on how a 26' steel boat worked in practice. I did make provision on it to add an autopilot later by providing the stub shaft to attach a sprocket or similar.
It is supposed to act as a leading edge flap for the sail behind the mast, which is laced to the mast. But these two reefs should be just as easy to execute as reefs on a more typical Chinese Lug.
Not having to dip the lug would be advantageous, even if it came with extra sheet lines and, perhaps, lower performance. Such can be fussy business at a time when getting things done quickly is of prime importance. Reading about the virtues of the Chinese lug pretty much sealed the deal, especially for the boat I was attempting to design. I went threw this thread quickly, didn't see what i have been wondering about for a few days.
The hull and the structure that support it, the rig and all the associated loads are all engineered together so they become a structural package.
There's no reason to provide more trim capability than that required at WOT with full tanks. If so there's really no value in these trim devices, because if they don't achieve a relatively flat pitch at WOT with maximum negative trims then they'll be very little use to adjust for sea conditions.
Pascoe, Marine Surveyor A wood boat is the sum of its many parts while a fiberglass boat hull is I recently came across a 1999 48' Ocean Super Sport that had been struck in the transom by another boat. Fiberglass construction is hand labor OPTIMIZED RACING BOAT DESIGN USING UNIQUE HIGH STRENGTH FIBERGLASS David Fecko of gravity without a loss in hull strength.
Yacht design concepts, custom hull designs, lighter and We have found plywood laminated with fiberglass and Kevlar to be the ideal materials for boat hulls layers of fiberglass. He's a type that's not going to be held down for long and will find a way to be successful again.
It turned out wonderfully and his web site has photos of it underway, with he and his son at the helm. Is it a vernacular style developed here for use here or is it a copy of some older boat from the somwhere else? The whole page is underlined in red and it automaticly replaces some of the words for spanish ones. If you right click on your flickr image you should be able to copy the url of the actual photo (ending in .jpg), or see if there is a bbcode option ready for you to copy and paste.
I had to edit many of the pictures because the boat was just in the background and I had to zoom in on it to cut out the people in the foreground. And for those towns like ours who are on the island beaches, it serves as transport to get to the mainland, as well as a tourism opportunity for tours of the estuary and to the ?water eyes? or ?ojos de agua? as they are called here, which are where the fresh water from the underground cenote system opens up from underneath the sea or estuary creating an area of constantly flowing fresh water surrounded by saltwater.
If you look at the link below, you?ll see that is it only one km from the dock to the beach across the estuary in this small coastal town.


If it is a similar technology to the controllers in modern electric cars then it probably does increase range by 5 times.
500% claim is worst case scenario comparison and really doesn't have much point in my opinion. Phil Bolger claimed it was the most weatherly of the 'traditional' rigs (he didn't like my idea at all). That would be the small matter of Lightning Strikes.Surely not a problem on your boat with your boat with wire shrouds and a length of chain over the gunnel,but what about the unstayed rigs?
If a good planing trim is achieved at cruising speed, typically trim is too low at top speed.
RIB boat * Nice and polupar design * Fiberglass hull and PVC tube * CE These are the basics of boat hull design used on RC boats (and real ones too!). Even if you had to recharge the batteries every time you docked, shore power is not expensive.
As the tourism industry develops here and the boys find themselves in better economic postitions, they could use torqeedos or other products that come along. Having a sail that comes close to reefing itself would be of great value in this situation. If the specification is interceptor, then surely one that occupies a greater wide of the hull could be the ticket. Learning about the different designs and their performance differences will help you Did you ever wonder where the lapstrake hull design came from for MFG's boats?
But I think the first nine pictures show very similar designs, just that some have a modified wheel house or deck or something else. I?m sure they work great for the fishermen at higher speeds, I see them every day speeding out in the mornings and returning in the evenings.
4000 watts is a good charge and you should realize that we are in a much lower latitude than in the states so the angle that sun hits us is better for a flat roof than in the north. I don't have permanent downhauls rigged on JOSS but can in minutes with multipurpose lines always available for such 'tuneing' and vanging when conditions allow wing and wing. What you have drawn, while it looks straightforward to the layman, would not set well at all due to the overly square shape of the sail. Mostly trim tabs and low stern drive trim are needed while getting to plane or at (low) cruising speed.
After reading such long threads I feel like I already know him and you and Daniel and others from their posts. So would you consider a Florida Mullet Skiff to be usable for the same purpose as the boats I pictured in the post above? But since we?re talking about tourism, you have to take into consideration how the pangas are used for tours and transportation. The ?taxi? boat drivers and tour operators have their 40hp Yamahas throttled down so low that they seem like they?re going to shut off after every ?put, put, put-put?. But I?ve never seen a gyro stabilized dish (like on RV?s for satellite TV) that was compatible with Hughes and worked on a boat.
There are good reasons the Chinese settled on the various sizes and shapes of batten lug they use and to be successful one should start there.
Based on Class rules, find minimum bow height required & decide if u need a forecastle deck. Read the literature like Junks and Sampans of the Yangtze and the Hasler-McLeod book before you jump head first into an empty pool. If the owner is one person and the captain is another, they general split the profit after expenses.
Unlike the fishermen who want to get out there as quick as possible, the taxi driver just wants to get his customers across estuary as cheaply as possible or the tour guide who goes slow so the tourists can see everything and feel like they?re getting their $120 worth of sightseeing. If you built a roof to replace the tarp seen in the above pictures (and below also), then you?d be able to place your panels there. The first time I came to Yucatan was on a Carnival Cruise and we had internet service all the way across the Gulf, so I?m sure it?s possible.
The other thing I considered was putting a pipe vertically through the hull just fwd of frame 17 (aft of the rudder) for a balanced steering vane setup - lock the main rudder and drive the small one via wind vane or autopilot.
While seemingly simple, the rig is very subtle at times and redesigning it without deep understanding courts failure. Or sometimes the captain has to pay a daily fee for the boat and handle his own expenses of gasoline, pay his helpers and sometimes even do the maintenance even though it?s not his boat. Unstayed masts with Chinese rigs are fine on boats with little stability and not overly large sails but I watched one break off at the deck on a boat that was suddenly pressed with a hard gust going downwind in a narrow channel with nowhere to head up to ease the pressure and insufficient time to ease the halyard. So even if I decided to invest in the hardware, the monthly service costs would add a real strain to my budget. The unstayed mast with a rather heavy Chinese lug on it is subject to whip when pitching and the inertia load alone can break it. You could probably increase the wattage of your motor to as much as 4kw with this system and still not need a huge battery bank.
Typical Chinese unstayed masts are very large at the deck in proportion to mast length and are extremely strongly stepped.
Every time you dock the batteries are being charged and there is no drain until your next customers come along. I use 2" aluminum 6061t6 aircraft tubing for my 1000 square foot sail and have broken several and the boom in a bad knockdown.
These were the rates that the customers were paying to Direct TV when Hughes took control of the internet client base.
Wood or bamboo would have died long ago and I am still using the same battens I originally rigged in 1985 with basically zero maintenance. But when I investigated the service two years ago the rates had gone up to between $100 and $200 a month and the bandwidth had only gone up to 1 Mbs, but they added a daily data cap.
Here is a pic of our main being bent on and the Big Eye Chicken junk sail it is derived from. So if you used too much in one day they would cut you off or make you buy extra megs or something.
This points as well as a gaff sail and it wonderful in light airs, reefs in seconds and is very controllable as to shape with the luff parrals.
So I decided it was better to just take the bus into town and use the internet cafes that are all over Mexico.
If a child wants to study middle or High School their parents have to send them to a larger town 2 hours away to live and study. So when the government started giving subsidies for the common people in fishing villages to buy boats and motors to fish with, the people in charge of the local governments made sure that those benefits and subsidized craft only made it into the hands of their political allies, family and friends. Sometimes I use my Mexican cell phone for internet access but it?s really slow and also expensive. That?s how Carlos Slim became the richest man in the world, on the backs of a 100 million Mexicans.



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