Adding Ballast to Daggerboard

As regard the ballast : I also agree with all members that it is not necessary for your dinghy size. It is done for only large dinghy when the capsize recovery is not doable by the crew usually, see for exemple the VX one
VX ONE-DESIGN - sailboatdata
As regard the maxi transversal force at daggerboard tip when the sailor use it to right up the dinghy after a capsize : I did this study for a 14' sailing dinghy, based on the weights and buoyancies at stake (i.e. not considering the visquous resistance of sails in the water, and/or any suction effect) , step by step from an upside down capsize, see here attached. Roughly, this force can be either at minima up to about 55% the weight of the sailor doing the righting up, or at maxima 100% of the sailor weight but then rather at the center of the daggerboard. I think that state of the art daggerboard and trunk designs can cope with such solicitation.
See also this video :Capsize testing an Ilur class sail and oar boat

 

Robert,

It sounds like your new boat has landed in the right hands.

"Like the boat isn’t light enough! Right?"
Wrong. Weight is the enemy, please keep that in mind while making any modification.

"Well, as for hiking straps I already bought the 1" braided rope".
Looks like webbing to me, it should be fine.
Next time, use "D-rings" instead.

Your response to Gonzo's comments indicates a lack of understanding.
The boat was designed to sail as is. Avoid changing it. Do not add ballast.
Not only are you the ballast but you are movable ballast, even better!
Try not to speculate on its performance, you need to sail her.
Do not add any ballast.

Yes, contact the designer, maybe you'll listen to him.
I guarantee he'll say: “NO, DON’T DO IT!”.

Fair winds, BB

 

Interesting, thank you.
Consider the above study reflects a short duration, relatively static event. Sailing with ballast will be for longer durations under dynamic conditions.

 

Hey Folks!

Let me first say, I really am going to sail her before I make any modifications in regards to ballast. However, and I don’t mean to stir up a hornets nest here, But, I still don’t see why a little extra weight at the end of a dagger board could be such a disadvantage as some of you have implied. I will admit I might have been a little over zealous when I said “100 lbs.” Maybe 25 lbs. is just enough. I don’t know. Just thinking outside the box here. But, I don’t even have to modify the dagger board. I can just build another one and see what happens. For instance, I’ve got access to some sheet copper. I think he said it was 1/4"x4'x4'. Well, I guess you know what I’m gonna say next. Yep! A two ply copper dagger board. You probably already know that copper is close to the weight of lead. Lead being .4 lbs./cu. in. and copper being .314 lbs./cu. in. So, if I build a new dagger board at the exact same dimensions as the present solid wood dagger board, the weight would be close to 85 lbs. I don’t think the present wood dagger board weighs more than 8 lbs. But, I’m just guessing. The point is it’s very light.

Anyway, this all just talk at this point. I gotta get her in the water and see how she sails even in light winds before I can make an honest assessment of this beautiful sailboat. I’m also going to build some oars first as well. Why? Two reasons. First, oars are a good back up when all else goes wrong. Second, I really want the exercise. You all wouldn’t know this, but Lake Lanier, here in North Georgia, can have winds of about 5 MPH, and then 0 MPH for a couple of hours. Yes, I could use the trolling motor I’ve got setup on the stern, but I really do need the exercise. No kidding here, I really do.

Hey Dolfiman, I gotta tell ya, I love that VX ONE-DESIGN. It’s one of my most favorite sailboat designs. I hope I get the chance to sail one some day.

The video of the capsizing recovery was quite impressive. It reminded me of an experience I once had back when I was young and spry and lived in Ft. Lauderdale FL. It was a time when I sailed something everyday. Well, cause it was my job. For a couple of years I think, that was all I did. Sailed Prindles and Hobies, Sunfishes and laser’s, and Windsurfers. And, I mean the original Windsurfers. We’re talking like back in the late 1970's. I can’t remember how many times while pulling the boom up the mast foot would pop out of the board and hit you right where you’d want it to hit you the least. If you know what I mean?

Anyway, one day my partner and I went out on the Prindle cause it was so windy no one wanted to go out. Since we were young, strong, and brave, or really dumb, take your pick, we decided we were going to test our sailing prowess. It was a strong 25 knot wind that day and we were out in 4'-6' swells. We were flying! Both of us hiked out as far as one could get. Then we literally did go flying. We pitched poled so fast we didn’t what happened. We completely capsized. Anyway, my partner standing on one hull and a rope tied to the other was pulling with everything he had. I went under water about 25' and pushed the top of the mast back up to the water surface. I think I came up for air about 6 times. But, we finally got her up and went back at it. It was a one hell of day at sea. Good memory actually!

 

Don't do it!Copper is quite expensive and very soft and the load at the point where the hull bears on the copper is likely to create a small crease that gets bigger and bigger with use,until one day it folds over and can't be withdrawn.For a bit of further reflection might I suggest that you consider how little actual leverage any weight on the centreline can exert on the heel of the boat?An apple carried in your pocket may well produce more righting moment as it is further from the centre of buoyancy.Simple mechanical leverage applies and once you are imposing weight outside the gunwale,nothing can be more effective,a few pounds applied a couple of inches from the centre is miniscule by comparison.If you need to feel the sensation of a boat that can't capsize then you need a hefty keelboat with a high ballast ratio,it won't be as much fun and it probably won't sail as fast.

 

It would be easier to sew a line of reef points on the sail for windier days.

 

Robert,

What did Mr Davis have to say about your proposed modifications to his proven design?
It probably doesn't really matter at this point as you seem hell-bent for glory to add ballast.

Good luck, wear a PFD.

 

Well, I guess I should have explained my copper dagger board idea with a little more detail. First, I’m quite aware copper and salt water don’t mix. And yes, in general copper is considered a soft metal. But, compared to what? Steel? Hell yeah it’s soft. How about compared to lead. Then it’s pretty damn hard. Here’s the thing guys, no matter what type of core material I’d use for a new dagger board, it’s going to be encapsulated in fiberglass and epoxy. For what it’s worth, I’m pretty sure that a Catalina 22 Sport has a retractable keel that has an iron core encapsulated in fiberglass and epoxy. So, I’m not talking about anything new. And since you brought up the leverage principal, there’s only one thing holding that 600 lb keel in place and it’s a 1" diameter bronze pivot pin. If had to take a guess I’ll bet thousands of lbs of force are applied to that pivot pin when a Catalina sails are laying in the water. My point is, I think you’re underestimating the strength of copper at ½" thick, especially encapsulated in fiberglass and epoxy. Now, as for your point of expense, you’re right on spot. I’d probably pay close to $400.00 just for the copper at market values. But, in my case my neighbor has had these copper sheets sitting around for years and he just wants to get rid of them. So, I see this as an opportunity for a new dagger board idea. Actually, it would be a lot easier to construct a copper cored dagger board over my original 2-piece wing design. But, I still think the wing design would be so cool.

So, “Hell-bent for glory to add ballast”. Well BlueBell, I guess you’re right. I am a “Damn the torpedoes, full steam ahead” kind of guy. Once I get an idea in my head I just gotta follow through with it, if not just for the sake of trying. If I’m really that far off with this whole “Adding Ballast” thing, it won’t be the first time I’ve failed. But, I tell you this, I’ve had a lot more successes than failures. And, I’m not afraid to fail this time. However, I still think I’m right about this “adding ballast” thing, I’ll just have to prove it to one day I guess. But, if I’m wrong I’ll present the evidence to you all here at this forum, and I give you my word that I will do so.

I will also give you my word that I will NOT make any modifications, or build a new dagger board, until I’ve taken this sailboat out in some meaningful winds and test her out. Well, except for the oars, which you’ll never talk me out of that one

As for Mr. Arch Davis, I had to leave a voicemail and have not heard back from him yet. But, it is the holidays.

Have a Great Today!

 

I'm pretty sure your guess about the forces on a Catalina 22 is based on an erroneous assumption.The lateral location and bracing of the typical drop keel isn't resisted by the pivot pin;it has to have a generous amount of clearance to allow for movement after a period of immersion may have allowed some rusting of the iron keel.Which means that like smaller boats with centreboards or daggerboards,the lateral forces are resisted by the bottom of the boat acting as a large stiffening web and an amount of bracing preventing the top of the case from moving.In the case of the boat under discussion this function falls to the battens along the top of the daggerboard case and they are aided by the large plywood brace that extends 2/3 of the way across the bottom panel and feeding their loads into the stiffener that goes to the chine.These are the elements that distribute the loads since you don't have a pivot bolt.The pivot serves as a location for the centre of rotation and has to resist gravitational forces while determining the periphery remains within the designed boundary.

A massively heavy daggerboard will be an encumbrance that sinks the boat beyond it's intended waterline,it will be a nuisance to transport and to lift into place,not to mention a hernia risk,and it will provide very little righting moment until the boat is severely heeled.Releasing the camcleat on the mainsheet will be much more useful in terms of taking away the heeling moment and before reaching this stag you should be some way beyond the gunwale with your body weight.Just do a rough calculation of the righting moment from the proposed daggerboard at 30 degrees of heel and compare it with what your bodyweight can deliver.

 

Hey Fellow Sailing Folks,

I got a chance to talk with Mr. Arch Davis today. He was very polite and listened to everything I had to say, which I thought was very generous of him with his time. Anyway, after describing to him that I would probably be the only one in the sailboat most of the time, and I was planning on sailing her in 20 knot winds, he said adding ballast would be okay. However, he did strongly advise against adding ballast to the end of the dagger board. He was actually very specific as to where I should place the ballast, the weight of the ballast, and that it should be removable. Mr. Davis suggested that 100 lbs. of whatever I use, could be placed on the port and starboard sides of the dagger board trunk right at the bottom of said trunk, at the keel, on the hull. 50 lbs. on the port side, 50 lbs. on the starboard side. He said it could be sand bags, and that it really didn’t matter what I used, as long as I had it in that location. Mr. Davis also suggested something I didn’t even think about. He said I should devise some means of holding the dagger board in place so that in case of a capsize, the dagger board didn’t fall out. He said bungee cords, or some sort of clasp system would work just fine. Mr. Davis also mentioned how fast this boat is even in moderate windy conditions. So, needless to say, now I’m really excited to get this boat in the water. Only thing is, I’m probably gonna have to drive to Florida if I want to go soon. It is so cold here right now, I mean like 20° at night and only in the high 30's during the day. Way too cold for me to get wet, even with a wet suit.

I also mentioned to Mr. Davis that I’d really like to have oars installed on the sailboat. I described to him my plan for stowing the oars through the bulkhead, the 8'-6" length of the oars, and the material I’m planning on using for oar lock blocks. His only concern was that I may have trouble getting the oar paddle sufficiently underwater. However, I explained to him that I already used an 8'-6" stick as a gauge and it appeared to me that the paddle would be well underwater. He seemed okay with the idea after that. Still, he’s got a point. It is rather marginal as to how well oars will really work on this sailboat that has so little draft. I noticed when testing with my 8'-6" stick, that the proposed handle of my planned oar, after pulling it to my body, will be at my upper chest height. This really isn’t an optimal height, in relation to ones body, for oar handles being pulled on the force stroke. I think the oar handles are suppose to be pretty close to the bottom of your sternum after the force stroke. So, this is one of those cases, when “Some study shows the need for more”. Probably should do some more testing with length and work-ability.

So, thought you all would like to hear what Mr. Arch Davis had to say. Obviously, he has confirmed many of your concerns with adding ballast. However, adding ballast wasn’t totally out of the question. I just wasn’t planning the use of it properly. Now, I know how to do it with confidence, and with the most efficiency.

Anyway, I had a wonderful conversation with Mr. Davis. He was such a gentleman and just a nice guy in general. I learned a lot and if I ever finally get around to building a sailboat, which is on my bucket list at the age of 66, I just might buy a set of his sailboat plans. This is the one I like the best of all the plans he has to offer.

Wood Boat Plans, Wooden Boat Kits and Boat Designs - Arch Davis Design https://www.archdavisdesigns.com/davis_penobscot17.html.

BTW, I found this picture that the original owner sent to me. You can see how high she rides in the water.

Have a Great Today Folks!

 

I did the performance comparison with a light or an heavy daggerboard, all others things equal. For this study (here attached), I quickly modeled a dinghy named A14 inspired by ACE 14 for at least regarding its main dimensions, weight (215 lbs) and sails area. The hull shape is derived from a previous project (Dolfi 4,08). The light (wood) daggerboard is estimated to 3,1 kg (6,8 lbs) , the similar but heavy daggerboard is at 46,1 kg (101,7 lbs). The solo sailor weight is 106,6 kg (235 lbs) in standard hiking posture (meaning his weight about 15 cm outside the gunwale). In the document attached are compared the rigthing moments, the wetted surfaces, the speed predictions when sailin upwind, beam reaching (twa 90°) or downwind (twa 135°) within 3 configurations :
- SA 10, 78 m2 (mainsail + jib) and with light daggerboard or heavy daggerboard
- SA 7,68 m2 (mainsail) and light daggerboard.
The heavy daggerboard never gives a better speed, just a bit more stiffness when sailing close hauled by wind > 12 Knots, but then, with just the mainsail and the light daggerboard, you can be more comfortable with even more speed when wind > 13 Knots. Same thing when sailing beam reaching, just a slight theoritical advantage within 15 to 16 knots of wind.

 

Thanks for the update!
I have a 17' sailboat with a box keel that the designer originally considered water ballast as an option. It seemed it was more bother than using the space for stowage and/or solid ballast.
Even 100 pounds in the bilge eases the motion.

 

"I went under water about 25' and pushed the top of the mast back up to the water surface. I think I came up for air about 6 times. But, we finally got her up and went back at it. It was a one hell of day at sea. Good memory actually"

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Exactly

what an incredible wonder it is to be young

My idea is to return to my first love: a small boat, and recreate the old sensations in my current old brain turns out to be a 1 Ton boat

Capsizing at a certain age is not fun. The usefulness of ballast is fundamentally for recovery after a capsize. 100 pounds doesn't seem like much to me, even 160 pounds on the centreboard.

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by the way

a beautiful boat

congratulations

 

Laser Stratos
and
Laser Stratos Keel, 154 lb

Laser Stratos Fin keel (Laser Performance) - Sailboat specifications - Boat-Specs.com https://www.boat-specs.com/sailing/sailboats/laser-performance/laser-stratos-fin-keel

The version with ballast ... the sensations are much more pleasant

 

Daggerboard cases and boxes can certainly cope with that much weight - in fact they can cope with dramatically more than the weight of one sailor, even in light boats. In 18 and 16 Foot Skiffs it's normal to put all three crew onto the centreboard for capsize recovery, which means one of them has to fit very close to the tip. So allowing for wet clothing, there's probably 300kg+ on the centreboard of a 16 or 18, with the weight spread evenly along the length almost all the way to the tip.

The OP's Ace 14 looks like a nice boat and the daggerboard case looks fairly strong.