Didi 29 Retro!

A Wolf in Sheep's Clothing!
I wonder if musicians can appreciate written music before they have heard it played? I guess they probably can otherwise how would they write it? Anyway - this is the first boat review I am prompted to do on a boat that has not actually been built yet. Its also the first one for which I have been prompted to include an exclamation mark in the name! You'll see what I mean . . . there will be more to come when we see it on the water.

This is an extraordinarily interesting design from a number of perspectives. When I first saw the outlines on Roy McBride's blog I responded with a short email commenting on the design which he immediately published, and the interest in this design has been immense.

Click on the pic above for an animated 3-D view on YouTube.

Note the planing underbody, powerful, high-lift keel, and the deep high-aspect rudder. Only the plum bow and the transom-sheer can be seen above water!

Classic topsides including the transom sheer, vertical cabin sides, classic bowsprit, and slightly raised bulwarks up front. Her moderately slender profile gives no further clues to the sportsboat lurking in her!

For all the world she looks like a classy and humble old gaffer. Originally gaff rigs had loads of sail (and sails) spread fore and aft on the hull as early technology couldn't support tall masts and high point-loads, or deep keels for that matter. So this rig is capable of hiding a vast sail wardrobe "at the ready" in a low-tech guise. Never mind the powerful assymmetrical on the 2 m bowsprit. Never mind the full roach gaff main, or the two headsails which can be used seperately or in combination, and sheeted right into the centre if desired . . . 

Space below is limited but practical and well used, with decent heads and galley. Headroom is limited at 4:3" - about the same as an RCOD or my Flamenca - but enought to get about in. Enough crew-berths for an offshore race, or family weekending at a pinch. Compared with say a Pacer-27 she is cavernous!





When I first saw this hull it struck me of the old days when people placed V8s in a "stock standard" looking VW Beetle, and proceeded to blow the socks off the Ferrari's of the day! While that is an unfortunately crude analogy, the element of suprise compares very well!

As you can see, the underbody of this yacht is pure sportsboat (without excessive beam and fat stern) - the flat planing sections at the back, long waterline, high aspect (bulb) keel and rudder, deceptively firm bilges, and quite easily-driven (slender) at that. Built from the well proven DiDi-26,  the dynamics are well understood, with the advantage of quite a bit more length. Construction from ply will keep it suitably light and very agile.

The topsides have all the styling cues of a proper old gaffer. Hahaha! This is where the fun really starts. Gaff-rigs, even in their old original form, are amazingly capable rigs. The well known sailing author Frank Robb wrote a convincing argument explaining his preferences for Gaff Rigs some years ago. In recent times, modern materials, technologies, and the IRC have made a clear winner of tall Bermudan Rigs with dominant mainsails however. Can this design change the state of play again? Probably not, but its going to be quite an interesting race in this example, especially if IRC is left out of the picture.

Off the Wind
Firstly, Gaffs are damn fast downwind, and in in all points except hard on the wind. Their centre of effort is much lower than a Bermudan rig, and the roach much fuller. They produce awesome power and penetration, whilst also being more controllable in very heavy winds - as the mast is far shorter -  so avoiding the instabilities of tall masts once they are over-powered or start rolling. More broach-resistant by far - which means you can drive quite a bit harder . . . On this 29 Retro, there is the small matter of a big assymetrical on that 2m bowsprit. Given the usual 25+ knots in the Mykonos race, I would be tempted to try it under the spinnaker alone. It will be astonishingly stable using just the bag, which is pulling far ahead of the centre of drag, whilst generating lift on the bow. As such, the rig is inherently stable, it shouldn't be able to broach at all . . . the planing underbody won't produce much argument from the hull, and the combination should be good for > 20 knots in the right hands!! Can't wait to see its first Mykonos race. Even with the main up, the gaff main is far more stable off the wind than its Bermudan counterpart, being far lower. Notice the spars are all carbon-fibre . . .

Light Airs
This rig offers a lot of canvass in many combinations. The hull is easily-driven and light. One tends to sail slightly looser in light airs anyway, so the gaff main will cope well. The two headsails could be flown in combination(s). It should be a killer.

Upwind in fresh conditions, Round the cans.
Established wisdom on gaffs suggest this will be its weakest point of sail, but I really suspect this is where this rig will offer its biggest suprise. Perhaps even the designer will be suprised! Why? Well typically, the fastest boats upwind are smallish, light and beamy, and benefit from generous crew weights on the weather rail. They generate huge power from the relatively high righting moment against the heeling force. L26s come to mind, and suitably crewed Pacer-27s, Melges 24s etc etc. Even Miuras are quite impressive in this role. But don't forget the RCOD. It's a slender hull, heels like hell, lacks power in the rig, but makes good angles and is easily driven. It moves nicely through a sharp chop on the water. Somehow they get to the next mark faster than you expect. This 29 Retro will do all that and more. The hull will track and point beautifully. The high-aspect (bulb) keel is good for plenty of lift, and its depth will provide good power at a fair angle of heel. The headsails can be sheeted extremely close as they don't clash with the stays. This gaff main is a very neat example - I don't see why it won't come in as close as a Bermudan main given the way the top-spar is fixed? The lower centre of effort is an obvious advantage. As a helmsman, in fresh conditions, I would optimise the headsail(s), use the main primarily to balance the helm upwind, and see how she goes. In lighter conditions she will reward a looser angle of sail favouring hull speed and this may be the way to get a good VMG. Some time with a GPS will be useful. One way or another, there is a lot more to this rig upwind than meets the eye.

All in all - this is going to be a very interesting boat to sail and own. There are many races she will do extremely well in, and will suprise the fleet in all circumstances. The beautiful looking traditional element is a joy to any yachtsman. She will dominate the bartalk, the press and the photo galleries. Having driven camera boats at various regattas I can just imagine Trevor Wilkins and Brenton Geach chasing after this baby, with or without the sponsors logos! I wouldn't want to be on the club handicap committee after the first race . . .
To add some further interest, I don't think this boat will need much in the way of winches - and the standing rigging will be very clean and simple. There is no need to get on the foredeck, and she will be easily handled by two people, making the element of suprise even greater!

This going to cause a lot of head scratching with sailors and designers alike . . .

Part 2 will come when we have seen her on the water - in 2013 I guess.
See Dudley Dix's Blog at http://dudleydix.blogspot.com/2012/06/more-didi-29-retro.html
See Roy's blog at ckdboats.blogspot.com for details on the build as it happens, and the kits.

Shaped by Wind and Wave

Dudley Dix's New Book!

Boats and boat-design have fascinated me for quite some time. There simply is no more interesting mix of art and science in existence. Nothing more likely to generate a good discussion about form and function, all mixed up with adventure, adrenalin, tradition and good living! I was therefore very happy to receive a copy of Dudley Dix's new book - in which he explains his personal perspectives on design priorities, and how they have been formed through his own experiences of living, sailing, and boat building in the "Cape of Good Hope", a.k.a. Cape of Storms!
As with any noble pursuit - sport, fine wine, oil painting, or the design of a classic yacht - the enjoyment of the product is enabled by an appreciation of the approach used, what the designer/maker was trying so hard to achieve, and how he/she got there. In the case of a yacht - it is a fascinating experience just to see the design - before the boat is even built or sailed - to see the how the designer has creatively tackled the multitude of challenges inherent in every boat design. Every case is a complex mix of priorities including considerations for cost, seaworthiness, comfort, manageability, type of build, performance, looks and many others. Just the shape of the hull underbody is an adventure story on its own! (Ch. 5)

Isn't it all done by computer these days? Err- no. When a yacht designer finishes at Westlawn or University or similar, they can tell how it float, balance and eprform, and not break hopefully, (plus a good few examples of good practise), but the philosophy and style of their designs is very much a product of personal creativity and personal values . . .

This is what Dudley's book is essentially about - what his values and priorities on yachts and boats are, and the sensible design techniques for meeting them. All this is underpinned from the perspective of an ordinary man working on a budget, maybe home-building. Much of it is related to his personal experience of growing up and sailing in the very challenging waters off the Cape of Good Hope, of dinghy sailing in the fresh winds of Zeekoevlei as a kid, his passion for surfing, and the experience of building his own keelboats. Then it goes on to how his career as a designer took off following the success of his first design "Concept Won" - which gained him a major international award, and gave him a basis for many of the very successful designs that followed.

As someone who has good experience of some Dudley's boats (ref the rest of this blog!), and has sailed in the same waters, I was able to relate directly to all of it, and was compelled to read the whole book from start to finish in just two days (its quite a lot of book).

As a reference book, the content is simple and very easy to read, ideal for the ordinary yachtsman or boatowner. It is not full of mathematics, rather it explains the elements of yacht design at a practical and concept level. It won't make you a designer, but it will give give you a very good insight into the elements of yacht design, including hulls, rigs and most inbetween. For prospective and amateur boat builders, it is a must - with great chapters on choice of material, building techniques, even options for turning the hull. For anyone sailing around the south tip of Africa (common these days), Chapter 18 is a must. This is a fine piece of reality, concise but sobering, and for some folk will justify the book on its own.

There is also a chapter on Ant Steward, the only man to who sailed around the world on an open boat one of Dudley's designs - a modified TLC19. Certainly Dudley cannot be blamed for this idea - Ant was on his own with this umm - amazing endeavour - but Dudley is uniquely placed to describe this feat, which must rate as possibly the most daring sailing challenge ever undertaken, along with the strengths and limitations of the boat used. In my opinion, there is nothing quite like this for bringing out the real priorities and needs of a sailing boat on rough waters . . . . its not called "Shaped by Wind and Wave" by accident!

It now has pride of place in my boat library, right alongside Dave Gerr's "The Nature of Boats", Adlard Coles (Peter Bruce) "Heavy Weather Sailing", Tom Cunliffe's "The Complete Yachtmaster", Joshua Slocum's "Sailing Alone around the World", and Frank Robb's "Handling Small Boats in Heavy Weather" (even though it is a bit dated now). I have dozens of others but these are the "must reads".

At USD 30 its very reasonable - copies are available from lulu.com - details on Dudley's website at www.dixdesign.com. An e-reader version is also available now.

Vickers 45

The Vickers 45 is another great cruising yacht with a strong Hout Bay connection. Designed by Dudley Dix, a great example was "Tantalus/Sweetwater/Vlakvark" - a Vickers 45 AC. Built by Brian Alcock (also Hout Bay), for non other than John and Rose Stockwell (also Hout Bay).  John chartered her for some years in the Caribbean, before selling her to a guy on the US East coast, who christened her "Sweetwater". She is now owned by a Canadian couple who have been all over the Southern hemisphere with her - including Australia and the Antractic, twice if I am not mistaken. Thats the sort of boat a Vickers 45 is. Basically a small ship you can do anything with . . .

Dudley tells me the Vickers 45 was originally commissioned as a "performance motorsailer". Well if there ever was a term open to interpretation it must be "motorsailer"!! In this context it means "proper fast yacht with a good engine and tankage", and generous accommodations.

Well of course the Vickers 45 is a motorsailer. It sails and has a motor just like most yachts. Confusing thing is it sails a hell of a lot better than most yachts - it really has a tremendous perfromance pedigree. As for the motor part, it has a 60-80hp motor, and very adequate fuel tankage. Built in Steel or Aluminium, this really is a go-anywhere vessel, fast and comfortable, and extraordinarily safe. . .

Where did you last see a motorsailer, or any yacht in fact, with a stability curve like this?

About two posts back I wrote that the Dix 43 would be my first choice as a cruising yacht, if asked to chose on the spur of the moment. Well in fact the Vickers 45 is really a Dix 43 slightly expanded - it just scales to 45' with no appreciable changes in the ratios. The Dix 43 is a formidable sailing boat - I won't repeat that all here - suffice to say it really is a class leader in contemporary cruising yachts. In fact the Vickers 45 is actually better than the Dix 43 - much of the advantage coming from being slightly larger.

Larger yachts have a significant mathematical advantage over smaller ones. Design theory shows that the heeling force on a yacht increases with the 3rd power of its length, while the stability increases with the 4th power. Essentially this means that on a larger yacht, the designer can make her more stable, faster, or lighter - than the same boat on a smaller scale. Its a virtuous circle as the yacht gets bigger. The scale of larger boats also accomodates the use of steel better than small ones, as the scantlings can be more accurately sized etc. And in todays world the use of furlers for the sails allows the use of sloop (or Marconi Cutter) rigs on large yachts - again with significant benefits to performance and stability. (Ketches may sound nice - but in reality this means two masts aloft, and an inefficient sail plan. Much better to have two roller-furling headsails if necessary, and a decent main . . .)

So the Vickers 45 is a real performance yacht. In one example the Vickers 45 "Two Jays" beat the Schumacher 41 "Swimlion" over the line between Richards Bay and Durban - notable as Swimlion was a stripped out racer . . .

As they exceed about 38-40', yachts start to become little ships (not including ultra light racing hulls and similar). Suddenly they have real accommodations like a house. They feel safe  - and statistically are unlikely to be knocked down. They sail fairly level. They are dry. They tend to be fast enough to make decent passages and they become really useful - for extended cruising, chartering etc - whatever the weather. The Vickers 45 comfortably exceeds in these areas, but as a package, is unique in its sailing performance, comfort and safety. It is interesting to note that a Shearwater 45 would easily fit inside a Vickers 45 hull! This is a large boat at 45'!

Generous accommodations - large aft cabin, galley and saloon.

The centre-cockpit version. It has a 2m shorter mast than the AC version. Keel options include the wing-keel as shown here, with reduced draft. The wings increase the dynamic effectiveness of the keel, and help to concentrate the weight low down like  a bulb. On a large hull, this is a sensible option.

Dynamically, the Vickers 45 is as good, possibly slightly better in fact, than the others in the Dix range. The signature "Dix hull" as I call it, has a flattish underbody, long waterline, a fine entry in the bow, fairly full stern but moderate beam - this makes for strong performance, limited pitching, and generally good seakindliness. In this example the engine is mounted centrally and entirely below decks - another benefit of size. Generous fuel tankage is in the keel! 500-800 litres depending on the model. The keel is moderate - won't break off, with a good balance between tracking and manouvering in harbour. Plus the weight is well centralised. Rudders can be either semi-balanced on a partial skeg, or full skeg on the steel version. Plans available for Steel, Aluminium, GRP or in fact wood.

Rig is Marconi-Cutter. The AC version is 2m taller.

In recent years, as it seems to me, yacht design has focused on either lightweight race boats, or production charter boats. And of course cats. Yachts suitable for circumnavigations, the Southern Ocean, and even the South African coast now seem increasingly rare. We get the odd Halberg Rassy wandering past, some Canadian designs, and the various Roberts designs we see routinely. No offence to them - but full keels with rudders on are getting a bit long in the tooth now. Of the contemporary go-anywhere fast cruisers, the Vickers 45 is clearly a benchmark . . .