A few words about rudders
before rushing to the harbour to prepare Ingeborg for the summer:

For those sailing on big stretches of thin waters, it makes sense to use shallow fixed rudders. Phil Bolger in USA did that a lot for his boats. He also introduced endplates to his rudders, which was a big improvement.
On FanShi, David and Annie successfully went for twin, shallow, fixed rudders with endplates. This solution even lets the outboard engine sit on the cl.

My waters are generally deep, except for the last few boat-lengths along the shores. I therefore prefer to have deep and efficient rudders. However, I am not so fond of the classic dinghy rudders. These become hard to swing as soon as the blade swings a little aft, and the whole mechanical concept is less than good.
If the boat has a flat and square transom, I therefore believe that the rudder shown below is better. The trick is to first make a ‘false transom’, hinged to the top of the real transom, like the backdoor of a station wagon (estate car). The rudder is then attached to that false transom. The distance between the top hinges, C and D, should be at least the same as between the rudder hinges, A and B. However, the whole (triangular) false transom needs not be symmetrical around the rudder. It can be offset to make room for an outboard engine or boarding ladder.
When this rudder is swung half-way out of the water, the tiller forces will not sky-rocket. In addition, the one-piece rudder can be made as strong as you like.

Arne

I like the shape of Buddy - more of a scow than a praam, which means more stability when you need to stand in the corners. Can you squeeze a bit more length out of 2 sheets of plywood scarphed end to end, Arne, up to 4.7m seems possible? Length is always good, when afloat and sailing, it's only bad when it has to be paid for in some way, so I agree with you when you say that you feel safer in a boat up to 17ft long. My Yorkshire Coble was 17ft long and weighed half a ton. The most exposed cruise I did in it was from Sennen Cove, Lands End to the Isles of Scilly and back, and I wouldn't have wanted to do that in a smaller, less able boat. Mind you, that was back when I was young and foolish, and I wouldn't do it at all, now, in an open boat ...

Thanks, Graeme,
for your many interesting inputs.

Largeish contra smallish.
It appears that you regard Buddy to be ‘largeish’. My eyes are calibrated to færings in the 14-17’ range, so to me Buddy is rather in the lower end of ‘normal’. I think Buddy is the smallest vessel I would cross the fjords in here (10-15°C in the water) without donning a dry-suit. Boats like Lasers and Mirrors are toys to me, not boats.

Centre-boards.
Broremann’s cb. was of 10mm galvanised steel and shaped like something between your version A and B. It was not terribly efficient, but its ballast effect could be felt. When hitting a rock, that ‘horn’ on the cb. would shoot up and forward with a mighty force. The area above the cb. trunk was therefore a red zone. The Model D is much safer. One may safely straddle over it and even sit down on the trunk. Great improvement.

Cockpit on cockpit...
I was out in Ingeborg the other day and refitted the freshly varnished tiller. While at it, I measured up her cockpit. As the diagram below shows, the cockpit of that 26’ Ingeborg is much smaller than the one in Buddy! Inspired by this, I have done small adjustments to the cockpit coamings and the front of the benches (wider benches, narrower footwell).

I am confident that Buddy, both the short and the long version, would be a fine little ‘Geriatric Gentleman’s day-sailer’...
What have I missed?

Arne

Hi Arne. Your feedback is illuminating, thank you. Now that I understand what you mean by “fixed ballast” (ie not shifted from side to side) I am in agreement. Stacking ballast to windward is not a good idea. I agree that ballast in a dinghy should be removeable, and I also think bricks or removable heavy ballast locked in a box is better than water in a tank – except when you don’t want it - which is why I am wondering if bags of wet sand might be a good compromise when sailing from a beach.

Perhaps a largeish dinghy can benefit from ballast at times. Certainly, the best place to put it would be, in theory, on the end of the centreboard. One advantage of Buddy’s arrangement is that a downhaul will not be necessary. (One would hope that in the event of a capsize, the board is in the down position, and securely locked in some way. My reason for slight hesitancy. Perhaps this is a reason for the downhaul. I would expect the board to be up when running down wind, a point of sailing which is also vulnerable to capsize).

I would define ballast on the swinging centreboard to be in the category of “fixed ballast” because it can’t easily be removed from the boat. If there is anywhere I would have liked ballast on the Golden Bay it would be on the centreboard, but this boat, being somewhat different from Buddy, I just don’t want any extra weight unless I can remove it at will. If you are happy with Buddy being a bit heavier, then your ballasted centreboard will be very effective, I guess.

I still think the central pin is a better arrangement mechanically, though I have never actually seen it done that way – swinging centreboards in New Zealand have always been pinned at the front bottom corner. Actually, in my country, dagger boards are traditionally made from wood, but swinging boards have almost invariably been made from steel plate. And strangely, centreboards here are almost entirely confined to dinghies and trailer boats, they are rare on moored boats.

To complete the discussion on centreboards, here are four typical types in New Zealand.

“A” was traditional for mullet boats and earlier trailer sailers. The board is made from steel plate, so the lifting tackle needs to be multi part. It is entirely outside the case and easy to inspect. The tongue to which it is attached spreads the load on the centreboard trunk when the board is fully down, which may be up to 90 degrees. When in the up position, all the weight is on the pin.

“B’ was an arrangement which I have seen once only, and that was on a high performance trailer boat I once had. The lifting wire remained in a grove around the circumference of the quadrant-shaped board. I think the quadrant board was wood and I think the tip was ballasted. It worked well, but ruined the already sparse interior accommodation. I have built an arrangement something like this on the off-centreboards of the scow I am building, but have since regretted it. It is too difficult to make a decent groove around the circumference of the quadrant, and too much risk of the lifting wire jumping out of it. To be on the safe side I have added a tongue, similar to A – and the result is a hybrid mongrel which I don’t like very much now, although I suppose it will work OK.

C is a simple arrangement which I have had on a couple of boats, with steel centre plates. Generally reliable, but if the plate is lowered too far, there is a small risk of the lifting wire jamming in the slot. Very noisy with the board down, when up to speed.

D is a bit like Buddy’s arrangement, and is the arrangement I have on Serendipity – again a steel plate, though, so it was very heavy to lift as it had only a single part lift. I have now added a small trailer winch to do the lifting. I am satisfied now, more or less. But with the winch you don’t know how much board is down – and with the pawl, it takes two hands to operate. I need one of Arne’s tiller lock arrangements! I am sure ballasted wood will be better than steel plate in this arrangement - strange, though, I've never seen it done that way here.

Ballasted drop keels have attracted a following in the larger trailer boats, in recent years, with a variety of lifting arrangements, from a simple chain block to sophisticated hydraulics. There are advantages and disadvantages, anyway not suitable for a dinghy I think.

My wooden unballasted swinging board on the latest project will be a first time for me. I do like the idea of shaped wood, rather than steel plate. I am reluctant to add permanent weight to this little boat, so will pass on ballasting the board, though I have thought about it.

The lock down floorboards in the centre part of the boat will be for two reasons – firstly, to allow the restraint of any heavy items placed in there. Additional light weight floor boarding will be added fore and aft because I have yet to see a dinghy that does not get a little water and mud aboard in some way or another, when in use. So I do not fancy cruising (and sleeping aboard) directly on the hull.

Our two boats are evolving in somewhat different directions, no doubt due mainly to different local customs, and different local requirements. It is of much interest to me to share ideas. Thank you.

Arne writes:

Anyway, I reckon that ‘Buddy’ will be capable enough for my waters (with some fixed ballast), and should row well enough to get me home the last mile when becalmed...

Ballast

I am not so sure if fixed ballast in a (presumably lightly constructed) plywood dinghy is such a good idea. It might be better to put the weight where it is useful, such as build it into the structure in the way of heavy bottom planking, or a foil-shaped centreboard cast from something heavy (such as reinforced concrete - easy to do).

I don't think I would want to do either of those things to Buddy because I am not convinced that a shallow, dish-shaped, flat-bottom hull can make very good use of ballast. Perhaps better to keep Buddy light. The crew weight, and the ability to easily reef, should be sufficient to keep a moderately beamy dinghy such as this on its feet. I don’t think that any practical amount of ballast could make a dinghy uncapsizable.

If ballast is thought to be necessary in a largish dinghy, perhaps if cruising single-handed, then I think it ought to be removeable. At first glance water ballast seems like a good idea. It is freely available if and when you want it – and just as freely disposed of when not wanted. However, it is no denser than the water it displaces, so it is very inefficient at providing stability at normal angles of heel, especially in a shallow-bodied vessel. (Perhaps this criticism applies slightly less to David’s SIBIM3.5 which I imagine to have a narrower bottom and deeper body. I am not sure). And then there is also the extra work of making the compartment watertight all round – with filling and discharging arrangements – and also, perhaps closed compartments in a plywood dinghy ought to be able to be ventilated when not in use. I am not convinced that water ballast, for an open dinghy, is all that much better an idea than fixed ballast, and certainly less efficient.

Concrete is more than twice as dense as water, so one might consider cast concrete bricks which fit perfectly and lock into place in that space under the floorboards. At least that concentrates the weight better, the compartment need not be watertight, and the weight is removeable for rowing, or when the boat is trailed.

Still, bricks (or sash weights) are not convenient to deal with, and not much of an answer. Ballast for a dinghy ought not to be carried around. Like water, it ought to be readily available when needed and readily returned to where it came from when not.

Back in the old days of mullet-boat racing, these shallow draft boats were big sail carriers. 

They were inside-ballasted of course - pigs of lead if you could afford it. Some, instead, had iron sash weights in the bilges. It is said that some them carried sandbags. (And sometimes they were stacked to windward too, which, for good reason, was against the rules).

Regarding junket boats, perhaps sand bags are worth considering. A few canvas bags could be sewed up, so that on days when you might like to carry a little ballast, they could be filled with wet sand and packed down into that space amidships, between the cockpit sole and the hull, and floorboards locked down. On the beach, taking on, or discharging wet sand ballast, in sand bags with draw strings, ought to be just as quick as pumping water, and more efficient as ballast because wet sand is denser than water.

I don’t think the Golden Bay wants ballast in normal conditions. (Nor Buddy). On my Golden Bay I think I might put floorboards over the central part of the hull, which can be lifted (hinged up) – and also securely locked down. Heavier items for cruising might be stored there – eg bottles of water (filled from the tap), beer, tinned food, tools etc.

But the idea of a few sand bags in that space, on windy days, is also starting to rather appeal. I haven’t measured it yet, but according to Google wet sand is about twice as dense as water. My grandson has a spare bucket and spade. I might just try it.