Your opinion of classic VS Modern Boat Design

[Polux]

Originally Posted by SV Windrush II

So my experience with my full keel heavy displacement boat is when rolling over a larger wave sailing down wind, it will heel to one side and then immediately heel to the other and back again, usually swinging 3-4 times before leveling out just in time to get hit by the next wave. Basicaly the momentum of all that lead in the keep and the narrow beam turns the boat into a swinging pendulum.
If almost straight downwind, I cannot use my autopilot at this point because it will not keep the boat heading straight enough to keep from jibing.
I'm sure all boats have some level of this problem but mine seams to be excessive. So I end up sailing closer a broad reach and tacking so the boat will stay on a even tack downwind.
....

That is why some modern cruising boats have those big fat asses and chines. The hull form stability is huge as initial stability and both working together damp and prevent the roll movement to a minimum. That is also why the autopilot works better on them. I believe that in fast performance cruisers speed also creates dynamic stability.

The worse boats in what regards rolling are narrow boats with a low CG.

[Stumble]

Windrush,

In those conditions about all you can do is keep reeling down until the boat stops rolling. Basically what is happening is that the boat is overpowered but since the hull can't blend it off by going faster the whole system becomes unstable. It's very much like towing a trailer with no tongue weight. At 5mph it's fine but hit highway speeds and everything goes sideways (literly).

By comparison take a look at

https://m.youtube.com/watch?v=S1IyZTsRIQo

. This in in 30+kn of breeze on a Pogo 12.50. The boat is rock steady because the hydrostatic lift of the water rushing past the transom wants to keep her flat. The faster she goes the more preassure on the transom to keep it flat. To mix metaphors the transom acts like the aero package on a F1 car and glues it to the road.



I really can't imagine wanting to heave-to in a boat like this, I would much prefer to run off in a survival situation. Even with just white sails the 12.50 is perfectly capable of sailing faster than a storm system moves, so worst case would be to bear off and sail out of the worst of it.

[SV Windrush II]

[QUOTE=Stumble;2302251]Windrush,

In those conditions about all you can do is keep reeling down until the boat stops rolling. Basically what is happening is that the boat is overpowered but since the hull can't blend it off by going faster the whole system becomes unstable. It's very much like towing a trailer with no tongue weight. At 5mph it's fine but hit highway speeds and everything goes sideways (literly).



Actually I was running with my main on the 2rd reef, any less canvas and it would role more because it needs the sail area for stability. I tried other sail combinations but at 25+ knot true wind speed it was the most stable.
Boat speed was between 7 and 8 knots with surfing up to 12 knots

[Stumble]

[QUOTE=SV Windrush II;2302288]

Originally Posted by Stumble

Windrush,

In those conditions about all you can do is keep reeling down until the boat stops rolling. Basically what is happening is that the boat is overpowered but since the hull can't blend it off by going faster the whole system becomes unstable. It's very much like towing a trailer with no tongue weight. At 5mph it's fine but hit highway speeds and everything goes sideways (literly).



Actually I was running with my main on the 2rd reef, any less canvas and it would role more because it needs the sail area for stability. I tried other sail combinations but at 25+ knot true wind speed it was the most stable.
Boat speed was between 7 and 8 knots with surfing up to 12 knots

Rock meet hard place. Sometimes all you can do is hold on and man the torpedoe.

[SV Windrush II]

One of the problems I see with the new wide hulls is the length to width ratio. The 50-60ft new cruising boats are designed after the Volvo and Maxi racers but do not have the length required for the sailing characteristics of the racers. Obviously there are other factors involved, but the length is a major one.

For example, the 100' Wild Oats is one of the fastest if not thee fastest monohull, pizza hull design, but has a 6:1 length to width ratio. The 50' cruisers virtually have the same width as Wild Oats but half its length!




The 50'-60' short fat shallow draft cruisers that have on the average 3.2:1 length to width ratio, giving them more of a design that is like the old sandbagger racers of the early 19th century.
The hull design worked well on the old Sandbaggers because of the movable ballast, moving the sandbags on the windward side of the boat. thus the name "Sandbagger". unfortunately the modern cruisers do not have movable ballast or canting keel as one of their options!

Here is a sanbagger of 1862, ironically resembles some of the new cruisers we see today.



The thumbnail is one of the designs I am working on, but its somewhere in the middle with a 70' length and 4.5:1 length to width ratio.

[robert sailor]

Originally Posted by SV Windrush II

One of the problems I see with the new wide hulls is the length to width ratio. The 50-60ft new cruising boats are designed after the Volvo and Maxi racers but do not have the length required for the sailing characteristics of the racers. Obviously there are other factors involved, but the length is a major one.

For example, the 100' Wild Oats is one of the fastest if not thee fastest monohull, pizza hull design, but has a 6:1 length to width ratio. The 50' cruisers virtually have the same width as Wild Oats but half its length!




The 50'-60' short fat shallow draft cruisers that have on the average 3.2:1 length to width ratio, giving them more of a design that is like the old sandbagger racers of the early 19th century.
The hull design worked well on the old Sandbaggers because of the movable ballast, moving the sandbags on the windward side of the boat. thus the name "Sandbagger". unfortunately the modern cruisers do not have movable ballast or canting keel as one of their options!

Here is a sanbagger of 1862, ironically resembles some of the new cruisers we see today.



The thumbnail is one of the designs I am working on, but its somewhere in the middle with a 70' length and 4.5:1 length to width ratio.

Great pic of Wild Oats..my opinion is that racers are designed to maximize their speed while modern cruisers are maximizing the size of the boat..different criteria altogether. That's one of the reasons that there is such a huge gap between them with modern racers reaching some amazing speeds and modern cruisers are more or less the same speed as some boats built 25 years ago. Yes there are some modern cruisers like the Pogo that are in a different class but I'm referring to modern high production boats. It wasnt that long ago that we associated multihulls with speed but builders soon learned that their buyers were willing to give up speed for comfort so multi's have gotten bigger and slower. Mono hulls are on a similar path but they haven't gotten slower they just haven't got faster. The builders are giving their customers exactly what they want. There are of course the outliers but they do small volumes.

[Stumble]

Wild Oats XI is far from the fastest boat her size anymore, and frankly is getting a little long in the tooth as far as design is concerned. The best current example is Comanche who has about double the beam (at the transom) as WOXI. Comanche's overall beam is 25'6" on a 100' vessel. As compared to WOXI's 17' beam at 100'.

Name.......L:B............ ratio
Comanche 100:25.5 ... 3.92
WOXI .......100:17...... 5.88
VOR (70') ..71:19 ....... 3.74
Beowulf (78') 78:16.4.. 4.76
Open 60 ... 60:18.7.... 3.2*
Pogo 50 .... 50:16.9 ... 2.9
Pogo 1250 . 41:14.75 . 2.77

* generally, there isn't actually a class limit on beam. Historically they have been getting wider, but foiling boats are going narrower.

What this really shows is that boats are three dimensional, and that L/B follows the cube rule. Also interesting is that L/b changes about .2 per 10' loss of length, and that WOXI is a weird outlier compared to boats of the modern wide stern version. WOXI is really much more in line with old school long, lean, and narrow vessels like Beowulf (the Dashews long range cruiser) than modern designs, which isn't all that odd considering she was launched in 2005.

[SV Windrush II]

Originally Posted by Stumble

Wild Oats XI is far from the fastest boat her size anymore, and frankly is getting a little long in the tooth as far as design is concerned. The best current example is Comanche who has about double the beam (at the transom) as WOXI. Comanche's overall beam is 25'6" on a 100' vessel. As compared to WOXI's 17' beam at 100'.

Name.......L:B............ ratio
Comanche 100:25.5 ... 3.92
WOXI .......100:17...... 5.88
VOR (70') ..71:19 ....... 3.74
Beowulf (78') 78:16.4.. 4.76
Open 60 ... 60:18.7.... 3.2*
Pogo 50 .... 50:16.9 ... 2.9
Pogo 1250 . 41:14.75 . 2.77

* generally, there isn't actually a class limit on beam. Historically they have been getting wider, but foiling boats are going narrower.

What this really shows is that boats are three dimensional, and that L/B follows the cube rule. Also interesting is that L/b changes about .2 per 10' loss of length, and that WOXI is a weird outlier compared to boats of the modern wide stern version. WOXI is really much more in line with old school long, lean, and narrow vessels like Beowulf (the Dashews long range cruiser) than modern designs, which isn't all that odd considering she was launched in 2005.

Thanks for the info, shows how up to date I am hahaha

but.. but.. I was a big fan of Wild Oats

[SV Windrush II]

Actually Wild Oats is still competing with the top contenders.

Won the 2015 TransPac

Was leading the 2016 Rolex Sydney Hobart race until it ripped its mainsail in half.

Not to shabby for "Old technology"

[TJ D]

Interesting thread.

We are firmly in the performance category, and will never go back to the old heavy boats. (I owned 3 full-keeled traditional boats previously) The advantages of speed are too many to list.

Most pleasingly, we've found that sailing in heavier conditions is actually MUCH more pleasant than on the heavy boats. Deep reaching (we never sail DDW), the boat just surfs down the face of any sea steep enough to break. The days of the big breaker shoving the stern around are long gone for us. Rolling is minimal gybing downwind this way, and it's generally faster too.

Upwind in bad weather, well, we're all in sort of the same situation. Nobody's sailing very fast anyway. We just reef down like everyone else and take it easy, trying not to beat up the boat or crew too badly. Honestly, it's not any worse on the ultralight than on a more conventional boat. We'll pound pretty good from time to time, but the boat's designed to take it all in stride.

For the record, our boat stats are 55', 24,000 lbs displacement, with a d/l of 72, l/b ratio of 3.72. SA/D is about 29
.
We have twin rudders, a 10' bulb keel, and 1600 lbs of water ballast moveable between tanks sited high outboard well aft. The water ballast is mostly a nod to the fact that the boat's designed to be sailed shorthanded, and it replaces 8 or 9 big boys on the rail.
We are also sporting hard chines.

I think that one of the things that's often overlooked by folks without much or any experience on the newer, faster, boats is simply that they get better and better the faster they go.

I understand Boatman's comment that a cruising couple won't want to be pounding along at 15-17 knots. It took us several thousand miles before we really got comfortable with it ourselves. These days, we think nothing at all about leaving the boat sailing happily along on auto with speeds in the teens.

Sure, if it's snotty out, and there's a confused sea running, we might have to slow down for Auto to handle the job, or hand steer, but for these new, bigger performance boats, 'slowing down' still means making 8+.

Are the modern boats more demanding to sail? You bet. Are they more sensitive to overloading? Absolutely. You can't bring 3 spares for everything along with 2 kayaks, all the kid's toys, 300 gallons each of water and fuel, and the kitchen sink without totally wrecking the boat's performance.

We've learned to be minimalists. It's worth it.

Anyway, bottom line- we're thrilled with the new direction our sailing has taken. It's fun again.

There is one big caveat here, though. Like Dockhead is fond of saying, you can make a boat light, strong, or cheap- Pick any two!

Getting to the performance of say, a Pogo, doesn't come without a pretty hefty price tag to have it built strong enough for most of us to feel confident on.

TJ

[SV Windrush II]

Originally Posted by TJ D

Interesting thread.

We are firmly in the performance category, and will never go back to the old heavy boats. (I owned 3 full-keeled traditional boats previously) The advantages of speed are too many to list.

TJ

Thanks TJ D, you actually gave me exactly the kind of information I was looking for.

[TJ D]

Originally Posted by SV Windrush II

Actually Wild Oats is still competing with the top contenders.

Won the 2015 TransPac

Was leading the 2016 Rolex Sydney Hobart race until it ripped its mainsail in half.

Not to shabby for "Old technology"

That sled has had some SERIOUS money put into her on redesign and rebuilding over the years. She's still a beast out there, and pretty much unbeatable in the right conditions.

Old my eye!

[TJ D]

Originally Posted by SV Windrush II

Thanks TJ D, you actually gave me exactly the kind of information I was looking for.

Sure thing. If you want to get into the weeds on some of the design philosophy which has worked so well for us, here is a link to a technical details page on our website.

Technical Details | The new Adventures of s/v Rocket Science

Our design is pretty similar to the one a few posts up, it'll give you some food for thought, anyway.

TJ

[daletournier]

Years ago I had a primrose design tophat 25,

http://sailboatdata.com/viewrecord.asp?class_id=6329

obviously a lot smaller than the boats discussed here. It was the mk3. In Australia these boats have an excellent reputation, they have circumnavigated more than once, traditional design, full keel ,49% displacement length ratio, narrow beam etc.. apparently super seaworthy and mine was a good one. Now, I cant or don't want to get as technical as some of you guys I'll just talk from my experience, in my opinion boats like this are pigs to sail! Mine didn't just roll down wind, it got a death roll! Very hard on auto pilots and me.
When I got on a modern design (or more modern) there just was no comparison, it sailed faster, flatter, manouvered better in close quarters, for me it was a no brainer, give me modern design, big bum, fin keel, spade rudder anyday.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[SV Windrush II]

Originally Posted by daletournier

Years ago I had a primrose design tophat 25,

TOP HAT 25 sailboat specifications and details on sailboatdata.com

obviously a lot smaller than the boats discussed here. It was the mk3. In Australia these boats have an excellent reputation, they have circumnavigated more than once, traditional design, full keel ,49% displacement length ratio, narrow beam etc.. apparently super seaworthy and mine was a good one. Now, I cant or don't want to get as technical as some of you guys I'll just talk from my experience, in my opinion boats like this are pigs to sail! Mine didn't just roll down wind, it got a death roll! Very hard on auto pilots and me.
When I got on a modern design (or more modern) there just was no comparison, it sailed faster, flatter, manouvered better in close quarters, for me it was a no brainer, give me modern design, big bum, fin keel, spade rudder anyday.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

Tell me about it, My 2 crew and I had to manhandle the helm for 7 days of 25 foot waves on the way to Hilo Hawaii, often breaking over the stern, sending us sideways every time. When I finally made it to the Philippines my new autopilot I installed in Hawaii was worn out. I have to send it back for a rebuild already.