around in pocket, I I think so

I have been thinking about the provision requirements. I have looked into this in the past for things like long distance hiking. The calorie requirements are somewhat less for sailing, at least on average. Fuel requirements are similar. I've also been thinking about electric power, and whether or not to use it for propulsion as well as for other things. I think it does make sense, if you need some ballast anyway, and can get the batteries low enough and dense enough. They would be particularly useful for a Round In Ten than had to sail through doldrums here or there, as do a little motor sailing to get a little more out of what little wind there might be, like just enough to go 1 knot in 1 knot of wind by sailing 120 degrees off the wind for 1 knot of apparent wind at 60. I think it also makes sense to have a little solar in addition to the wind turbine, for just this reason. Wind turbine will not do you much good in the doldrums. Question, is motor sailing with solar and wind, or stored and recovered wind energy, still in keeping with the rules?

Anyhow, getting back to food, I like the idea of fishing along the way, if for no other reason than to make things less boring. A better strategy than getting little fish all along the way might be to stop and fish where there is good fishing to dry and salt the fish and restock your provisions. I would be somewhat concerned about attracting sharks in a smaller boat such as this. The steel hull is starting to make more sense if only for this reason.

For making water I think a manual pump, combined with catching rain water, should be sufficient. Maybe water for 30 days and food for 100 days might be sufficient, even if the trip takes a year or more. The initial 100 days of food could focus on the nutrition you are unable to obtain at sea, but otherwise you might in this way be able to sail indefinitely. Heating fuel might be electric, with vegetable oil as backup where the vegetable oil can double as both food and fuel, or maybe you can render some oil from fish or fowl. I won't be bringing a crossbow with me for albatross though. Apparently that never turns out well.

Initially I might even be tempted to put to see with no water, and provide all water by pumping and collecting, in order to start off with more food, including some fresh food, including watery citrus fruits like oranges. In a pinch if the hand pump watermaker broke, and it didn't rain, you would still have your 60 oranges to get you back to safety. Once your oranges run out, or as they run out, you can replace their weight with fresh water and keep 30 days in stock. So I suppose for calculation purposes you could still assume 30 days of water, and 100 days of dry food, and just count your oranges as water and not as food.

So 30 days of water = 30kg = 66 pounds
100 days of dry food = 60kg = 132 pounds
Electricity to heat 1 litre of water per day, by say 80 degrees = 100 watt-hours
That seems high, but in wind you should have enough wind energy to do it, and in the doldrums you could preheat your water.
You could still have vegetable oil or fish oil as backup, for a little simmering lamp, and reading lamp, should your electrics fail.

So how much weight does an extra 100 watt-hours of electricity per day weigh? The nasty bit might be that it is at a fast discharge rate, even if you heat your water at high solar or wind energy output. The 100 watt-hours for 1 litre could be perhaps 250ml at a time, with 10 minutes of heating time, so 150 watts. If your solar and wind energy systems provided 150 watts peak, you wouldn't always have to drain 150 watts off the battery, but when you did, at a 5 hour discharge rate you would need your battery capacity to be about 75 amp-hours, so this seems doable as you might want double that anyway. You would just switch everything else off at tea time, or porridge time, or soup time, or whatever time it happened to be.

So it provisions could be as little as 200 pounds for 100 days, and you could restock fish for another 100 days for half your diet, that could give you a range of 200 days, for perhaps 9600 nautical miles averaging 2 knots. I guess it would make sense to double that, or triple that, but the other option would be to accept defeat and stop and visit places along the way like Capetown, or Port Elizabeth, if the weather is fine. ;-)

So how does 400 pounds of provisions change things? 200 pound skipper, 400 pounds provisions, 600 pound boat and equipment, 600 pounds ballast? If I could afford as much as 600 pounds of lead ballast out of 1800 pounds I could possibly go to a skinnier boat that might sail more like a micro-Vertue, or a micro-Pinky, or at least a micro-Pinky when loaded to the gills with dried fish. 1800 pounds over 10 feet is a displacement-length ratio of 800, and when down to final 100 pounds of provisions it would be 670, which I think is getting down into Westsail 32 territory. That coupled with being able to lean 200 pounds over the side now and then could make the boat a fairly decent sailer, even if the average speed is still only 2 knots. Half the speed of a West Sail 32 is not that bad really. Double the fun right? ;-)

 

kennedy,
i think that is interesting for you also this thread:

http://www.boatdesign.net/forums/boat-building/manies-ten-51428.html

 

The bulbus bow is for use all the 10 ft waterline length.
Yeah, build it is not a problem: part left and part right, double cone, heat with a blowtorch and take a hammer.
A professionist few minutes, no professionist of course more.

 

Thanks Windraf. Yes I understand the bulbous bow. Very good for pushing the hullspeed envelope, but I am more concerned about maintaining even half that in adverse conditions. Still worth experimenting with for sure. I searched for some information on early fishing schooners and such, to get a better feel for the displacement when loaded light and heavy. Came across this wonderful book online. Lots of great historical information. Not sure how practical for our purpose, but a wonderful read. Perhaps we could take it with us when we go. ;-)

https://archive.org/details/reportonshipbui00hallgoog

 

WindRaf.

A few things to think about with your design.

1.) Steel may not be the way to go. It is heavy for its stiffness and thinner plate is very difficult to weld without a lot of distortions. True. The boat may go together faster, but the steel needs to be treated against corrosion. This requires expensive paints and/or hot zinc or hot aluminum coating. And before that is applied it all must be sand blasted. Every inch. Add to that the fact that any significant scratch in this coating can quickly lead to a fatal hull breach, due to corrosion, due to thinness of the proposed plating. Aluminum would be far better, if you want a metal boat. If I were you I'd consider: 1.) plywood/epoxy, 2.) foam composite, or 3.) aluminum construction.

2.) the almost two ton displacement will be very hard to move with limited Sail Area (SA). Water Plane Area (WPA) has little to do with necessary SA, especially on a boat as heavy as an ocean going Ten. SA is usually calculated based on the displacement of the boat, in cubic units (cubic feet, in the USA and cubic meters, everywhere else). The SA is calculated in the following manner: ((Displ. in cubic meters)^0.667) * 10 to 20. 10 is the lower S/D limit and 20 is the upper one. Now for a 1.75 ton boat the system is quite simple, as 1.75 tons equals 1.75 cubic meters (m^3). So, for a real modest S/D of 10, your boat would need: ((1.75)^0.667) * 10 or 14.5 sm of SA. This would call for a very tall mast, with a jib only rig, or a very long bowsprit, or a combination of the two. with the base of the sail plan extended one meter past the bow, you would need a sail hoist of 7.25 m, almost two and a half times the length of the hull. And that's if the mast is stepped on the transom. The mast and bowsprit would most likely have to be taller and longer than this. Getting to the tack of this jib (the outer one if there are two), when you need to, can be a big problem.

3.) Getting the boat to sail down wind (which it would be doing most of the time) reliably is a major design consideration. With the original Yrvin 10, the plan was to use a centerboard, mounted in the bow of the boat, and twin rudders. The idea was to sail down wind with the centerboard retracted, giving the the boat a huge lee helm (which is what you want in this case). When it was necessary to sail up wind, or to heave to, the centerboard would be lowered, giving the boat a weather helm, making it easy to sail up wind. My approach was similar, except the sail plan, not the underwater profile would be changed. To sail down wind, the jib would be set and sheeted in somewhat. Because it is so far forward (see attachment), it would cause the lee helm I need. For sailing upwind, the jib would be furled.
Your boat needs some sort of system to do the same. It could use an electric auto-pilot or a wind vane. But such are relatively easy to break and often hard to repair, especially at sea on a tiny boat. I felt it was better to design a boat which would inherently have these tendencies.

Just a few thoughts.

 

1.) Steel may not be the way to go...

I agree with this but I don't think the sandblasting followed by epoxy would be that difficult to do, inside and out, as it is a very small boat which makes even the more tedious and expensive things much less tedious and expensive. I do think other materials are better for such a small boat, but I think everything is worth considering for such a project.

2.) The SA is calculated in the following manner: ((Displ. in cubic meters)^0.667) * 10 to 20

I think this is too much of an empirical generalization to extrapolate down to a 10 foot 1000 to 2000 pound boat.

3.) Getting the boat to sail down wind

I do like the idea of a simple Finn Dinghy type centreboard well forward combined with a large Finn Dinghy type rudder on the transom. Upwind with some weather helm the rudder gets a little extra angle of attack for efficient lift, and the delta centreplate, however crude, provides a lot of lift for its area before stalling. Downwind the plate can be lifted and the big rudder can act more like a big skeg, so whatever steering gear you might set up it might not have to work all that hard, depend on the rig and other things. Still I think there are a lot of ways to go here that would still work downwind, even in such a short boat.

I think the real challenge for a 10 foot 1500 to 2500 pound "ship" is that it is so big it you have to go both wide and deep, which doesn't favour a high metacentric height; but the payload requirement for provisions doesn't leave much for ballast and so the center of gravity is not much lower than the centre of the volume, so you don't have a lot of righting moment. What you do have going for you though is like a dinghy you can shift human ballast and perhaps some stores as well, as long as you are not totally packed. Still I think there is a way to carry sail effectively, but nowhere near as much as your formula would suggest, which is also not a real requirement. A smaller boat will have more drag for it's weight for a given speed, but it does not have to go as fast. So it does not need as much sail area for it's weight.

 

Steel might indeed not be the optimum build material for a small boat but there wouldn't be any small steel boat if it didn't had some advantages.

-It's relative easy to work with.

-Repairs can be carried out with a $50 stickwelder,available in almost every part of the world.

-Cut/grind/reweld is an extreme bonus......easy/cheap/fast.

-Steel is randomly available.

What you save in building cost might be consumed by maintenance but this is spread over a longer time frame.

A few students build the Dutch steel "Lelievlet"..
https://www.youtube.com/watch?v=06_eI0PqwV8

 

You end up with more righting moment than you might think. Heavier stores end up below the waterline, as the hull is so deep. I believe Yankee Girl had no ballast at all, or at least no outside ballast. Her keel was barely a forward and aft extension of her hull, the old "skeg and cutwater" profile.

But there are two kinds of stability:
1.) initial and
2.) ultimate.

Initial stability is that that you get at low angles of heel. It is the sort that is quite reliably predicted by meta center height. This is the type of stability you need for carrying sail, as you want to carry your sail at low angles of heel.

Ultimate stability is the sort you get at high angles of heel. This is the kind that will save your boat, if she's ever capsized. It will cause her to pop back up right. Most racing dinghies have very high initial stability, but very low ultimate stability. Many boats designed for blue water cruising have the opposite. A blue water ten takes this to extremes, so is pretty much condemned to carry a cropped working rig.

My proposed design would have outside ballast, but the amount would be quite modest. Maybe 300 lbs (136 kg). It's intended to insure ultimate stability, as the boat gets lighter in the later stages of its voyage.

I stand by my formula, which BTW, is not mine. it is standard in the boat design industry. I know of boats that have made successful voyages with S/D's of less then 10, but not much less. One Felicity Anne had an S/D of about 8.50. Another, Bris IV, I believe, had one of 7.50. With much less than that, you are simply kidding yourself. You now have a sail assisted boat, not a sail boat.

Such may be fine in the fierce winds of the high latitudes, but will be quite helpless anywhere else. And I'm not sure a mere circumnavigation of Antarctica will really count as a voyage around the world. If I were doing it, I'd want to cross the equator at least once, to keep my claim on the safe side.

So. Keeping this in mind, how slow a speed are you willing to tolerate? 2 kts? 1.5 kts? 1.0 kt? As your S/D goes down, so too does your average sailing speed in moderate weather. And the slower you go, the more likely you are to exhaust your stores before reaching port.

 

Guys,
First, I wrote 'compare', with a fast formula, between them sail areas of different boats, do not calculate the sail area of a boat.
Here there is no time, and my English is not enough to make lessons of naval architecture, but if you want to go into that of the theory of <plan carrier>, maybe you can find it in the book of Juan Baader
This is the formula
S = C x Lg x lg
C is the coefficent.

Second, about Ten I opened a mini google blog where are drew three models: plywood, carbon fiber, and steel.
All three materials are valid.
Here we are talking mainly of the steel. The steel model provides thickness of 3 mm for the bottom and 2 mm for the high sides, and deck in plywood. With this thicknesses are built boats long up to 10 meters (33 ft).
The final displacement of my Ten steel is 250 kg heavier than the carbon fiber.
Steel ten is designed especially for steel.
What we must not forget is that the weight of each Ten, of any material, 70% is not the hull, 70% of the weight is the same for all.
The steel has great advantages: cheap, simple, very strong, ability to integrate tanks in the structure, making watertight compartments during the construction of the hull and so on.
The steel hull is better be built by a professional, because the welds have to be done in a workmanlike manner and controlled with the ultrasonic instrument.
But even so, it will not cost much more than one fiber built in the backyard: with what you save in money of many pounds of epoxy, fiber, foam, divin cell ecc, you pay the professionist.
Only the steel hull will make professional, then if you want to do the rest yourself there will be a lot of work to do, and this can be done in the yard.

Of course, only to explain.

 

The trouble with stores for such a voyage is that water is no heavier than salt water, fresh drinking water is somewhat lighter, and food tends to be lighter still. This means if you fill the boat too much, like a cargo ship, it's center of gravity will be above the centre of buoyancy. The only remedy for this is either additional lead ballast, or a higher metacenter of better initial stability by making it beamier, or a combination of the two. If you do it too much with beam alone you will need considerable freeboard on order for it to be self-righting, and that adds windage and raises the centre of gravity further. These problems are inherent in high length-displacement ratios with low ballast-displacement ratios and cargo that is less dense than water.

The sail area matter is of lesser importance than stability and righting moment. In lighter and moderate conditions you can add sail area, but usually at the expense of a higher centre of effort. You can shift ballast, notable the skipper, and so you can generally go faster in moderate winds and settle for going downwind in more sever conditions. If the boat is too beam it can have stability problems fore and aft in addition to sideways. The problem I think is inherent in a boat of any length where you try to exceed length-displacement ratios above 500 without compensating with a low centre of gravity through either high ballast ratio, or a deep lead bulb. The saving grace is if you mostly want to go downwind. Broad reaching is harder. Beam reaching harder still. Close reaching and going upwind very difficult.

But none of this is impossible with a good design. There is no hard and fast rule that Length-Displacement ratio cannot exceed 500, or that the SailArea-Displacement ratio cannot be less than 10, or that the hull cannot be steel. You have to look at the complete picture, and I think everyone is doing that here. In the end any of these designs need to be tested on paper, through models, through sea trials, and ultimately through a voyage. It's a small boat. It is reasonable to go straight to a prototype and sail it and see what happens in increasingly difficult sea trials. There is nothing wrong with making mistakes. They are not just inevitable in design. They are essential. Hopefully we don't make fatal mistakes, but short of that it's all good.

I think these are all good ideas and all good designs worth testing. It's a really interesting challenge and I hope to learn a lot from this, and hopefully make some mistakes of my own before you all beat me to it. You all have a good head start, but I am pretty resourceful when it comes to making mistakes and hope to catch up quickly. ;-)

p.s. I recall reading Juan Baader's book once upon a time. Great stuff.
The formula is a good one, and you have to think about it awhile to get it.
I am sure he explains it in his book well and I will have to dig it out again. Thanks.

p.p.s. Just found this on You Tube...
https://www.youtube.com/watch?v=r4g-Xt131jQ

"The Sailing Yacht" by Juan Baader
$1.50 in Hardcover from Amazon
http://www.amazon.com/The-Sailing-Yacht.../dp/0393032205

 

WindRaf, your design "ten" has always struck me. It is a new design, I do not know if sail well and safely, but at first glance it is interesting. So I tried to dig a little deeper into it. Based on the information that appears on your website, which is public and I have not seen any "warning" regarding the use of it, I tried to build a model of your boat. I thought everything could be built by developable surfaces but, as I try to show in attached files, I conclude the following:
- The lower side is a developable surface that can be easily built .
- The bottom seems to be a ruled but not developable surface.
- The keel is completely non-developable.
- The bulbous bow seems to be an ellipsoidal cap which, in my opinion, even a professional in forging metals may have serious difficulties to build.
After studying the case, I would say that the proper construction system of this model would be GRP by mold or maybe strip plank.
Where do you think I'm wrong?

 

each kilogram put under the waterline lowers the center of gravity, also if is a kilogram of feathers

 

True, but you soon run out of space below the waterline if it is feathers.

 

this is the semplificate profile that i used for see the interiors, but you can also see, with a little immagination, that the bulb is build separated, and after welded to the keel. So your devolpement is not the real development of the system

 

The other advantage of this bulbous bow is it provides some extra protection to the precious cargo immediately behind it. Important consideration for a long voyage. ;-)