Ballast - Keel or not to Keel?

[konzine]

Hello!

This is my first post here and First off I have to say this is an awesome community you guys have. I'm fairly young, 21, and there are not a lot of people around my age that I have found to be into woodboats, or boats in general.

About a year ago I got into boating by a strike of luck, I suppose. I was at our Local bay (I live in Oregon), and I saw a BEAUTIFUL sail boat pulling up to dock in the harbor. The owner immediately could see my interest from the dock and invited me over to take a closer look.

Now, at the time, I had no idea what I was looking at, all I know was that it was gorgeous. Weeks of research later I came to find out it was an S&S New York 32, one of only 3/4 left still flying.

I was hooked from there on in, and have since built 2 wooden boats on my own. My first was a complete disaster, I still have it and she does float.... but not very well! We are talking Huckle Berry Fin status here. My second attempt went much better, and I decided to try a Sailing rig. Now, I had never been sailing and thank god I didn't drop this badboy into some harbor because she capsized on me about 5 minutes out in the Columbia river.

And alas I learned my lesson on Heeling!!

So, I am in the works of building a long-term "pocket-yacht", of my own S&S inspired design. My design also included a prop motor, just incase I want to take down the sails and have a little fun. I've been looking into Ballast designs and ideas, and I'm stuck between a rock here.

My question is, the boat is gonna be around 25-28 feet long, and I do want to run sails. I know that a Keel will do the job 100%, no questions asked, and god knows I got the lead for it, but I was thinking about going with a Water-Filled ballast. My only issue on this is, I don't really know if a water ballast will be able to stablize a boat of that size. I.e. I don't want to get my little brother out there on the gorge and have the first gust of wind roll us.

However, I do like the idea of a water-ballast because of the ease of use and being able lighten the load, and reduce drag, if I ever just want to flip on the motor and go for a spin.

At this point, budget is not of issue. My question is, and it's directed more towards those who have seen both Keels and Water-Tanks, would it be better for me to just run a good 5000lb Keel, or get a Water-Tank with a pump system and run that for days I just fele like 'romping' on the motor?

Click here is my design Idea! (http://img266.imageshack.us/img266/5388/boatcopy.jpg)

Thanks sooo much! And again, awesome awesome community I'm so happy to found out there are people of similiar interests out there. I was starting to think this was a dying culture :(

[Todd D]

If you really want to sail, you need a keel. Water ballast is generally high in the boat and is moved from side to side as needed. The problems with water ballast are that is takes time to move it, so a series of rapid tacks is generally not possible. It also takes power to move a significant weight of water. You either need a LOT of battery power, a gas/diesel driven pump or a generator. All of those spell weight and MONEY. Finally, because all water ballast does is combat heel by being pumped to the high (windward) side of the boat. It will do nothing for leeway (boat sliding sideways).

A keel generates hydrodynamic lift (like an airplane wing). That lift acts counter to the heeling moment generated by the sails and also works to decrease leeway. A deep, foil shaped keel will let the boat sail to weather. Without a keel of some sort, the boat will never point higher than 90 degrees to the wind direction. Even then it will make significant leeway. The deeped the ballast is located the less you need to combat heel and provide righting force.

There are alternatives to a fixed ballast keel. One option is a balasted moveable keel. A moveable keel can either be a lifting keel or a swing keel. In either case the keel needs to have a proper foil shape. You can also use a centerboard, which is another type of moveable keel, but with no significant ballast - only enough to keep the board down. Centerboards either pivot or move straight up/down.

Finally, 5,000 lbs is a LOT of ballast for a 25'-28' boat. My 36' ketch only has 5,000 lbs of lead.

[Thorne]

Designing boats can be a fun but very expensive hobby if you skip the book-learning part and jump right into designing and building boats. There are a few Naval Architects on the Forum, and they really know their stuff -- they have to as it is their profession.

As you discovered with your first boat, designing your own boats can result in non- or semi-functional boats -- and in potentially life-threatening situations for you and possibly others.

That is NOT a process you want to consider for a larger boat unless you are independently wealthy and well-insured. There are many designs in the rough size and shape of your desired boat, so start by picking up a few boatbuilding books and see what other designers have done.

Best of luck!

[konzine]

Thank you for the great replies!

I must confess, I am not going into this blind. I actually have an uncle who builds boats for a living, but they are fiberglass. Though, he has done a few woodboat projects in his time, I definitely will be thinking about safety first. I have actually ordered 2 books, which this website has recommended to me actually.

Again, budget is not going to be an issue right now for me so I'm kinda looking for the best of the best regardless of price. Of course I can't dive into a 6 digit project but I can handle quite a bit for now. So no idea is too big at the moment!!

[Bob Cleek]

You will find many safe and excellently performing boats for sale these days. You'd do well to purchase one and learn to sail before you embark on designing a boat of the size you are contemplating. Until you really acquire the knowledge and experience necessary to design boats, particularly sail boats, your next launch isn't likely to be a lot different than your last two, except that it will be a lot more expensive, and maybe somebody might get hurt in the bargain. Even if it does float and doesn't turn turtle, you'll probably be stuck with it because "designed it myself" is the kiss of death when you are trying to sell a boat.

If you want to build a boat, and that's a good thing indeed, consider the many fine designs in the WB Magazine "Store." Start with something small first. Build the dinghy you'll need for that larger "boat of your dreams."

First... baby steps.

BTW, as for "water ballast," (below the waterline, we're not talking about trim tanks in large ships here) think about it... How well does a boat sail when it's' half full of water? And how much space in the boat does that water consume... half? Water isn't "keel ballast." You want something heavier than water. A boat that's ballasted with water is no different than a boat that is sinking.

[Ian McColgin]

The drawing is pleasingly fanciful but the profile and section do not appear to be of the same vessel or to any porportion I can understand.

It may make sense to learn a bit about sailing before making your own boat for a number of reasons, a big one being what works and why. Sailing with diverse people on diverse boats will give you a better understanding of what you actually want (and can get) in a boat. If you put energy into some restorations you'll gain valuable insight into different building approachs and why some are better in some applications than others. For example, you might not know what the shelf and clamp do, much less ways of putting that part of the boat together that are less trouble prone than others.

Finally, you'll find that rudders turn better around a straight axis or, if that's a seperated lead at the bottom of the rudder, why putting the lead in the form of a hook is not normally considered useful.

Most of all, learning on and from different boats is really fun.

G'luck