How heavy is your ballast ?

I’m in the process of selecting a ‘lump’ of lead to make a ballast and am wondering how much I need.
From the plans section on the Footy Web Site, I see Angus Richardson’s Moonshadow used a ballast of 225g.
I would be very grateful to receive some information as to the weight of ballasts being used ‘out there’.
Are the wider designs using heavier ballasts?
Thanks in advance


I have a couple of footy’s now.

The easiest thing to do if your building from a design of known displacement is to build everything else as light as you can, and use the maximum ballast possible.

My boats are as follows:
Razor 3 (total approx 430-g, ballast 230gm (8oz))
AWK (total 500g, keel-12oz sinker (so about 340g))
Looking at a Ranger- total 300g, so will be looking about the 200-225g mark

Hope this helps


Hi Scott and Phil
may I suggest another way to look at ballast in general.
In order to get a good lateral stability on models, it is a common practice to select the ballast/bulb weight as a ratio bulb/boat going from 60% to even 70%
Example :
for a model total weight of 400g , chosing a ratio of 65% , the bulb will weight 400 x 65% = 260g
The point is that for the construction will remain 400 - 260 = 140g and that include all the weights escluding bulb
With a ratio of 60%, the available margin for the construction will be 160g


I like that idea. I’m assuming that this will work for all classes of yachts?

The other method I’ve read about is to float the boat, and add weight to get it to sit at the specified water line.

Claudio’s discussion is excellent, Phil…but Scott has given you a practical approach, too. For Claudio’s 65% example to be achieved with a 400 gram boat, you will need to build a light hull in the 30-40g range, use small servos, lithium batteries, and a very light rig…so that all of that doesn’t 140g. Because of that, Footys having ballast ratios of greater than 50% are challenging for many builders (people tend to over-build Footys based on their experiences building larger boats.) Careful building using light materials gives ballast ratios around 60%. Ratios higher than that are rare as hens’ teeth in Footys displacing 300-400 grams, though certainly possible for boats with displacement of 400 grams or more.


Hi Guzz,

Yes this is valid for all model boats.

If the model is properly designed, you will achieve the same ballast weight of around 59%-60% as a minimum.

Below 60%, still provide acceptable stability with light winds, if then the boat start heeling over 30/35° for more ther 5"-10", then is time to change the sails.

One of the most popular models, the IOM, has “on the Rules” a displacement of 4000g max. and the keel can go from 2200g to 2500g. If you esclude del fin weight of about 140g, then the ballast alone will vary from 2060g to 2360g .
The ratio will be in the worst case : 2060/4000 = 51.5% and in the better case : 2360/4000 = 59.0%

Often to increase righting moments some ones increase the hull draft as such that the fixed lenght keel, starting from the hull bottom, will increase the distance between the ballast/bulb and the water line. This “trick” do not pay off very much since deeper the boat is, in relation to the lenght and beam, greater the drag will be.

Hello all contributors to this thread,
Thanks so much for the wealth and variety of ‘spot on’ information you’ve provided.

I did a float test this afternoon (in one of the larger rectangular plastic IKEA storage boxes which are just perfect for the job without needing to use too much water). The result was rather a worry because to get the bottom edge of the transom up to water level require a lead of less than the 160g I used! A 260g lead had the transom bottom edge more than 1cm under water.

Prompted by these results I disassembled the boat weighing all components, with the following results:
34g Rig
34g Hull
8g Receiver
8g Rudder, tiller arm, pushrod
28g Servos (Bluebird 380 max & 306 max), tray, screws, sheeting arm
32g Fin
24g Battery (2/3 AAA 4.8v 210ma)

Using a lead of 160g would give a ballast ratio of only 50’ish %
Using a lead of 260g would give a ballast ratio of 60’ish %
May be I’ll aim to try and achieve a 55’ish 5 ballast ratio with a lead of about 200g and accept that the transom will ‘drag’ or should I aim for a 50’ish% ratio with less transom ‘drag’?

I’m afraid my hull hasn’t the volume to carry a bulb of sufficient weight to get any where near a ballast ratio of 60%. My next strategy (before thinking about a new hull) is to save some weight from the one area I think there is any weight left to save – the rig. This is a Una A rig with a mast of 600mm but, as a prototype, it has much adjustability built in to it and I know it has some heavier than necessary components. Once I’ve had a test sail and established the correct balance points I hope to save a few extra grams on the mark II version. I’m sure saving grams from higher up will make a much more worthwhile difference on righting moments than any saved from lower down. I just hope it’s enough to make a noticeable performance difference.

Do boats with ballast ratio’s of 50-55% have any chance of performing well in windier conditions, assuming you’re ready to be the first to ‘change down’ to a smaller rig?

As usual, any thoughts on the above would be received with interest
/Users/philtyler/Pictures/iPhoto Library/Modified/2011/6 Mar 2011_2/IMG_0892.jpg

Sorry, I didn’t manage to insert the picture.
Is there a way of doing this without needing to provide a URL?

I have looked at your individual weigths, and there is nothing alarming. Your weights are probably less than a lot of boats that are sailing competitively with 8 oz bulbs and 15 oz total weight. This implies that your hull is not designed with enough displacement (it isn’t fat enough, or it doesn’t have enough rocker).

But the rig weight is high, and you can probably use a smaller rudder servo.

When you checked your hull in the water, were the rudder and keel underwater, or sitting inside the hull? The underwater appendages (including the bulb) all add to the the flotation of the boat, depending on how much water they displace. So you will get an additional ounce or two of flotation from those items, which can be added to your bulb.

Which hull design are you using?

Hi Walt
The float test was done with everything in ready to sail positions and I simply taped the 2 ballasts to the fin, one after the other, to see the difference, so there’s no gain to be achieved there.
The design is one of my ow, I called ‘Red Dwarf’ (I’d be happy to include pictures if some one can tell me how).
Thinking about your comments about a lack of displacement, I set out to design a norrow’ish hull to fit diagonally in the box so it’s probably a lack of rocker causing the problem. Since I can’t do much about that now, I’ll persevere with the modifications I can make then, if necessary, go for a Mk II with more rocker.
What’s a sensible but light’ish target weight for an A Una rig, please?
Thanks for the feedback

To attach pictures, use the “reply to thread”, then hit “go advanced”. Then find the paper clip icon, which lets you add attachments.

Regarding the rig weight, I measured my own A rig, and it is exactly the same as yours. I am using a 3/32 stainless steel Z-rod, and everyone else is probably doing the same. I am using 0.156" (4 mm) carbon tube for the mast and boom, because the Z-rod fits nicely inside it. Most other people are using 1/8" (3mm) carbon tube, which is lighter, but you need to attach it with shrink tube or whipping with thread (I am too lazy). Take a look at Scott Spacie’s rigs in the photo section of the FootyUSA website, under Huntington Footys (he made the rigs on many of the top Footys).

Regarding the dragging transom, there are several possibilities. You might be able to take 1/2 oz away from the keel by using a light wood, like basswood. You can also move the battery forward to tilt the boat a little and get the stern out of the water. A lengthwise strip of light material (depron foam sheet?) under the hull can also help raise the hull.

Also be aware that the stern will raise about 1/8" (about 3 mm) when the sails fill with wind.

Thanks again for the feedback, which I’ll start working on next weekend.
Meanwhile, here’s a picture of the disassembled pieces of ‘Red Dwarf’ and a profile shot to see how much too flat she is.
I can’t believe I didn’t see the paperclip in Advanced. Oh well
Regards and thanks again

Hi Phil,

If you don’t mind some constructive, or in this case construction, criticism I have some weight saving suggestions.

From the photo it looks like you’ve created your deck structure from a plywood sheet. There is much more wood and weight there than is required for the stresses a Footy experiences. The inwales need only be a 5 mm wide strip of 1 mm thick multi-ply aviation type plywood. Main deck beams should be made from balsa, no larger that 5 mm wide x 2mm thick stock, the 5 mm side mounted vertically. You will need one to brace the mast tube area and one on either side to brace the keel fin in the middle of the fin. The area around mast tubes can be supported with cut offs from the balsa deck beams.

I don’t know if you can get 1/64th inch aviation ply in Basel. I think that it converts to .4 mm or there about. Anyway, I mount the base ends of my mast tubes in a sandwich of balsa flanked by this thin ply sheet that is glued to the floor of the boat. In my case the mast tubes are only 3 inches long so I need some kind of base to make up the distance to the bottom of the boat. If your boat is fiberglass be stingy with the epoxy or it may pull dents in the hull as it shrinks slightly.

I would also use this thin ply to create any flanges that you need for attaching the deck film to. Remember, for Footies less is more. Alternatively, you can add a strip of balsa cut 2 mm square to the inside of the inwales to fatten them up for the deck film glue. If you go with the balsa, sealing them with Ca along the top edge will give you a surface that you can sand smooth for better adhesion of the film.

A lot of current Footies sheet their rigs from the bow. If you go with the bow mounted fairlead use balsa/.4 mm ply sandwich beam (same balsa beam material with the thin ply on both sides, mounted horizontally this time). This is made by laying a thin bead of Ca on on the balsa then placed on a slightly wider strip of the ply. The same is done for the other side. Then the overhanging ply is sanded back flush with the balsa. Makes a stiff, light weight beam that you can screw into (remember to start with a pilot hole first).

Another improvement would be to get more controls for the aft corner of the sail. I have explained this many times before so I won’t go into it here. Reference some of my other posts by using the search command at the top of the page, I believe my latest explanation is in the multihull forum on a thread started by Roland about his tri project.


As far as i can see your weights all seem ok.
My A rig is just under 30g, my B rig is 26g, and my storm rig, 22g

I’ve just started making a depron ‘Ranger’ by Bill H, which is a 300g displacement. If i can drop my battery weight from 64g (easy to do, but i don’t want to give up too much duration, else i’ll need more packs (and its more to forget), and save another 10g dropping from my 2 channel 27Mhz rx to a micro one… then i should be on for about 200g ish of ballast,making just over 60%