Are modern yachts designed wrong?

[30boat]

If you are seriously considering building your own boat, plan on building three : first one for your enemy, second for a friend and third for yourself; it's an old adage.

I admire those with enough mental stamina to even consider building a boat.I've restored two in my life and would never do it again.There are too many good second hand boats to be had for me to justify the effort and time and of course, cost.

 

[Twister_Ken]

I admire those with enough mental stamina to even consider building a boat.I've restored two in my life and would never do it again.There are too many good second hand boats to be had for me to justify the effort and time and of course, cost.

With you there. If money were no object I'd love to commission a yacht to be built, but as to picking up the adze myself, no way.

 

[pmagowan]

With you there. If money were no object I'd love to commission a yacht to be built, but as to picking up the adze myself, no way.

Sure it is all good fun. I like the challange. The boat I have currently has already had a lot of work done on it and we are lucky that it fitted into our shed with only minor alterations to the gable. I still need to get it back in to lift the lid and replace the deck and coachroof.

 

[doris]

I have read this thread with fascinating and am amazed at the number of posters who fancy designing their own boat.
Personally my perfect boat would be a Rustler 42 hull and rig with an RM style interior.
Stephen Jones spent 6 months just on the keel of the 42, from the mouth of the great man himself, and it all works brilliantly. Quick for a heavy boat and amazing comfortable.

Sad is the way most builders stay with an interior that is like an Edwardian gentleman's club. They are mostly the bloody same. That's why I love the RM approach. One can change interiors but not the laws of hydrodynamics.

The only major new concept I see coming in the future is the horizontal wing extending sideways to windward. There is serious work on this down under but it needs to in the original design and to convert the extraordinary conservatism of the yachting world.

Yachts in 50 years time......now that is the serious discussion point.

 

[flaming]

The only major new concept I see coming in the future is the horizontal wing extending sideways to windward. There is serious work on this down under but it needs to in the original design and to convert the extraordinary conservatism of the yachting world.

Yachts in 50 years time......now that is the serious discussion point.

Called DSS (and the foil goes to leeward...)

Undoubtedly the most exciting development to "mainstream" sailing in the recent past. Of perhaps limited value to pure displacement boats, but for boats that get up and plane they're adding a massive amount of righting moment with hardly any additional weight. And, crucially, the ability to reduce the drag in the light that the fat bottomed Open 60 style boats don't have.

Plus the righting moment increases with the speed, so the faster you go the more you can sheet in, and the faster you go.... People who have sailed them report it's a very different experience, and I very much doubt that anyone's got close to exploiting the concept to the full yet.

A mini transat has been built but didn't race in last year's race. Hopefully it'll line up next time round, but I feel that the concept is advancing so fast that it's possible that they'll want to design a new one by then!

 

[lw395]

Called DSS (and the foil goes to leeward...)

Undoubtedly the most exciting development to "mainstream" sailing in the recent past. Of perhaps limited value to pure displacement boats, but for boats that get up and plane they're adding a massive amount of righting moment with hardly any additional weight. And, crucially, the ability to reduce the drag in the light that the fat bottomed Open 60 style boats don't have.

Plus the righting moment increases with the speed, so the faster you go the more you can sheet in, and the faster you go.... People who have sailed them report it's a very different experience, and I very much doubt that anyone's got close to exploiting the concept to the full yet.

A mini transat has been built but didn't race in last year's race. Hopefully it'll line up next time round, but I feel that the concept is advancing so fast that it's possible that they'll want to design a new one by then!

It's equally possible it will get banned by many 'authorities'.

The irony of that is surely that we've known how to go faster than a mini for decades now, just have a multihull instead of a ballasted monohull.
Through the ages, yachts have been very influenced by rating rules, even fishing boats and other commercial craft have been influenced by various tonnage rules relating to harbour dues etc.
When you take all that away, what remains is balancing performance (of varying sorts) against cost and safety factors.

 

[JumbleDuck]

Before the early GRP MABS came in the few that did cross oceans were invariably old workboat styles - lifeboats, pilot cutters, fishing boats etc because that is what they could afford.

Really?

 

[JumbleDuck]

from Wikipedia: Reliable caliper-type disc brakes were developed in the UK by Dunlop and first appeared in 1953 on the Jaguar C-Type racing car. Actually, disc brakes per se were invented in the 1890's, apparently

The Citroen DS (1957) was the first mass production car with disc brakes, and the Daimler SP250 (Dart) was the first to have four of 'em.

 

[JumbleDuck]

Happy to admit that some long-keelers do look absolutely right and they can be beautiful boats. To do, I think, with the shape of the bow and the pinching in towards the stern, combined with long overhangs and, generally, a very sweet sheerline. They may be anachronistic, but certainly good-lookers.

You don't need a long keel to have a pretty, traditional hull.

 

[JumbleDuck]

It hasn't improved profitability, boat yards are still going bust, but it has changed yachting from a sport for the very rich to one many ordinary people can aspire to.

Hmm. Shall we compare the cost of a 1970s starter boat (Corribee? Warwick?, Leisure 17?) living on a swinging mooring with the cost of a 2010s starter boat (34 footer at least) living in a marina?

 

[Tranona]

Really?

Those are Johnny come latelys. Think of Eric Tambs, Joshua Slocum, the Pyes and of course the great Tilman, never mind our RKJ and Saint Tom and many others pre and postwar who used workboats or workboat designs for their ocean passages. And don't forget the hundreds of Westsail 32s which would not have been out of place in Norway in the late 1900s.

 

[JumbleDuck]

Those are Johnny come latelys. Think of Eric Tambs, Joshua Slocum, the Pyes and of course the great Tilman, never mind our RKJ and Saint Tom and many others pre and postwar who used workboats or workboat designs for their ocean passages. And don't forget the hundreds of Westsail 32s which would not have been out of place in Norway in the late 1900s.

Sopranino was built in 1950. Winibelle II was built in 1932. Lively Lady was built in 1948. They all crossed oceans, they all predated "the early GRP MABS" and none of them were remotely, let alone invariably "old workboat styles - lifeboats, pilot cutters, fishing boats etc." Of course some people did sail in boats like that, but ocean crossing yachts designed, shaped and built as yachts have been around a lot longer than GRP.

 

[Tranona]

Sopranino was built in 1950. Winibelle II was built in 1932. Lively Lady was built in 1948. They all crossed oceans, they all predated "the early GRP MABS" and none of them were remotely, let alone invariably "old workboat styles - lifeboats, pilot cutters, fishing boats etc." Of course some people did sail in boats like that, but ocean crossing yachts designed, shaped and built as yachts have been around a lot longer than GRP.

But a minority none the less until boats became mass production items - and as the endless stream of Spray and Archer copies shows there are still many who see workboat styles as the right way to go.

Even some of a certain Mr Paine's designs gave a nod to shapes of the past - even if the bits you don't normally see are not quite the same!

 

[flaming]

It's equally possible it will get banned by many 'authorities'.

The irony of that is surely that we've known how to go faster than a mini for decades now, just have a multihull instead of a ballasted monohull.
Through the ages, yachts have been very influenced by rating rules, even fishing boats and other commercial craft have been influenced by various tonnage rules relating to harbour dues etc.
When you take all that away, what remains is balancing performance (of varying sorts) against cost and safety factors.

There doesn't seem to be a clamour to ban it yet, and it was fitted to the line honours winner of the last Sydney Hobart.

 

[mrming]

By the way, despite it showing initial adoption down under (as well as on the Swiss lakes), the DSS foil has actually been pioneered by a Brit, Hugh Wellbourn.

 

[JumbleDuck]

But a minority none the less until boats became mass production items - and as the endless stream of Spray and Archer copies shows there are still many who see workboat styles as the right way to go.

It would be interesting to know what the relative numbers were.

Even some of a certain Mr Paine's designs gave a nod to shapes of the past - even if the bits you don't normally see are not quite the same!

Like hulls based on Scottish fishing boats with NACA aerofoil section long-ish keels underneath? Yes, I believe such nonsense has been know to occur ...

 

[JumbleDuck]

By the way, despite it showing initial adoption down under (as well as on the Swiss lakes), the DSS foil has actually been pioneered by a Brit, Hugh Wellbourn.

<googles>

Oh right. Basically it's a stabiliser fitted to a sailing boat. What's the advantage of putting it horizontal rather than vertical?

 

[mrming]

Exactly as you say - it's a stabiliser. As far as I understand, sticking it out the leeward side creates lift / righting moment and also dampens roll. It also apparently works better the faster you go (which seems logical).

Info here: http://www.dynamicstabilitysystems.com

 

[jimbaerselman]

I've been fascinated by this thread - very interesting.

It is possible to separate and explain certain boat behaviours more precisely than just classifying "long keel" and "fin keel" characteristics. This range is, anyway, a spectrum of layouts from the old Brixham sail trawlers (keels nearly the length of the hull) to those long, thin 3 metre deep aerofoils supporting a lump of depleted uranium.

So, lets look at some characteristics in a different way.

1. Inertia around the yaw axis. ie, mass at distance from the yaw axis. High inertia - catamarans and boats with heavy ends; slow to spin, whether from wave action, rudder, or rig balance. Low inertia, lively in yaw, especially in a seaway, and easy to spin with rudder.
2. Distribution of underwater vertical surfaces Spread from end to end (longer keels, catamarans, skegs) damps any spinning motion in flat water, reacts to waves in disturbed conditions (I've been for a spin a Morbihan eddy at full flood stream in a long keeler). If concentrated at the centre, lively in yaw, especially in a seaway. More rudder action required
3. Inertia about the pitch axis. Light displacement = low inertia. Pitches easily, uncomfortable to windward, and (unless wave frequency matches the boat's pitching frequency) does not displace much water, so faster. Heavy displacement = high inertia. Easy motion to windward, shoves a lot of water out of the way, higher drag.
4. Hull curvature Affects yawing moment due to heel angle. Rudder to prevent the yaw adds to the heeling forces. Combined with low yaw inertia and low yaw damping, toxic.
5. Directional stability Tendency of boat to keep itself aligned with the water flow when under way. Function of the distance between the boat's centre of gravity with its centre of lateral resistance. The centre of lateral resistance has two cases; rudder fixed (further aft) and rudder free (further forward). High directional stability gives good self steering, but difficult steering when going astern. Neutral makes busy steering activity, high ability to manouevre, easy steering astern. Avoid negative . . . add a skeg if that's what you're suffering!
6. Keel aspect ratio. Affects leeway, and ability to take the ground. Long shallow keels create large tip vortices, and have to sail free of the wind to keep boat speed. Bilge keels similarly. However, both can take the ground, opening up a wider choice of tidal destinations. High aspect ratio keels sail with less leeway, closer to the wind, but structural design to support them suitably is demanding, while accidental grounding can be damaging.

And I've left out many other criteria -

No wonder boat design is a compromise. Comfort versus performance. Depends on length of trips, how often they are made, how much time you're on boardd in harbour or at anchor, how often and in what conditions will the engine take over, whether you can avoid weather or not.

One certainty is that longer boats are better at most things and certainly more comfortable. But cost more . . . or are too big for small/aged crew.

 

[Twister_Ken]

The only major new concept I see coming in the future is the horizontal wing extending sideways to windward.

I think we had this with sliding seat canoes!