Which sub 37 ft yacht to cross the North Atlantic in?

[geem]

The article extols the virtue of carbon construction which many production companies have embraced by making the process cost effective. It also points to the need of expensive self-aligning bearings to accommodate large rudders - true - and the need to regularly maintain them, also true, the maintenance point being relevant to all.

Incidentally, why do you keep issuing chilling warnings like, "Read Morning Clouds assessment of rudder failure on their boat and why they no longer ocean cruise with a spade rudder."?

Where does it say that in your attached article, which opens:

"Despite the fact that I had up until that time owned three yachts that had spade rudders, had covered tens of thousands of miles aboard them, and but for a bad case of metal fatigue might never have had a concern about their use, my immediate reaction was to rule out having one on our next boat.​

​

"But I learned a lot at the time as we fabricated a new rudder from scratch; not least in terms of how difficult—and expensive—it can be to do it right.​

Before going on to conclude:

"Whilst I still prefer the strength and security that a skeg offers, I accept that a properly designed and constructed spade rudder can be a viable choice, but it must have some form of protection ahead of it in the form of a keel or prop skeg to reduce the risk of collision damage. One of the reasons I am not a fan of twin rudders is that this is virtually impossible to achieve with this configuration. "​

​

Which as I mentioned above is exactly the direction Hallberg Rassy is going, but that's another story !!

Where did I issue a chilling warning? I suggested you read the article which you have now done. The main point of their article was that spade rudders are maintenance intensive. There is a lot of load on a rudder that isnt supported at both ends

 

[dom]

Where did I issue a chilling warning? I suggested you read the article which you have now done. The main point of their article was that spade rudders are maintenance intensive. There is a lot of load on a rudder that isnt supported at both ends

There is indeed a lot of load on an unsupported rudder as there is on a modern aeroplane but we don't see biplanes much anymore because the engineering problem has long been solved! As to your chilling warnings, your words were:

"Read Morning Clouds assessment of rudder failure on their boat and why they no longer ocean cruise with a spade rudder. [not true] No doubt that production boats are value for money. They get you afloat for less cash. The builders have worked out how to make something look good. Dont expect it to be full of superb engineering [not true, Hallberg Rassy use this system].​

​

To say a skeg is only a bit of grp is fine as long as you appreciate it is the stuff your boat is built from! Its still a bit of grp in front of a skeg hung rudder that provides protection to an otherwise vulnerable bit of grp suspened at one end by a plastic bearing in the case of modern production boats. [true, but the engineering issues have long been solved]"​

In terms of cruising, it comes down to choice and second-hand older boats are cost efficient ways to get afloat for many. That said, comments along the lines of "they don't make em like they used to" principally reflects an age/income demographic as opposed to anything engineering related.

 

[Baggywrinkle]

Incidentally, twin rudders allows them to be shorter, so less leverage than a single long spade.

Full skegs have rudders which are not balanced, this makes the forces on the steering system higher than a balanced spade.

A solid skeg behind a fin keel is a lever attached to, or part of, the hull which when subjected to enough force may breach the integrity of the hull, rather than snap off at the main bearing like a spade.

A balanced skeg rudder creates a scissor action on its leading edge where the forward part of the rudder blade swings to port and starboard of the bottom of the skeg, warps, branches and other debris can get trapped and sieze the rudder or break the steering gear.

Balanced spades are applied extensively to single and twin-screw vessels, including small powercraft, yachts, ferries, warships and some large merchant ships, they are also employed as control surfaces on submarines and other underwater vehicles.

Spade rudders are not some modern work of the devil designed to kill unfortunate sailors, they simply have different failure modes to skeg hung rudders.

I used to be a bit concerned about spades as I come from a family brought up sailing in the 70s - every time my dad goes aboard a Moody he points out how Angus Primrose died on one, it got a bit tedious after a while - but such prejudices live on. Remember in the good old days where it wasn't just rudders or keels, it was entire boats falling apart? Chainplates failing, bulkheads de-laminating, interior doors that would sieze in their apertures when the boat was under sail? The veritable Centaur needed its keels beefing up, Contessa 32s often had chain plates strengthened and spreader plates fitted.

A boat is a combination of all its strengths and weaknesses and this obsession with one small aspect of design does get a bit tedious.

What changed my mind about spade rudders was a charter holiday in Greece where I watched an errant German skipper slam his chartered Bavaria 50 into the rocky bottom of Sivota harbour.

The skipper was a nutcase and his crew not much better because the "space" he was heading for was between two small open fishing boats and it was obvious from the sloping beach to the right of the "space" that it wasn't going to be deep enough.

Sure enough the boat came to a very loud and sudden stop, the bow lifted about 50cm out of the water - the bow thruster was visible - and all the crew standing on deck fell over. He'd taken the full force of impact against the rocky bottom on the aft tip of the rudder. The boat with equipment and crew must have weighed around 13 metric tons, and it was doing 2-3 knots. Once they had composed themselves he sheepishly motored off further into the harbour and found a deeper berth. I walked past later to have a look at the damage, and apart from a large chunk of anti-fouling and gel coat missing from the rudder, the boat was still floating and it left the following morning to continue its charter. Don't know what actual damage was done but the boat still functioned.

Would that impact of punched a fixed skeg up into the hull causing structural damage? Like grounding a moder fin keeler does? Who knows.

 

[Bajansailor]

I remember in the late 80's there was a chap advertising in the classified ads of YM, looking for other Moody owners who might have been in the same boat as him - seems like he had a Moody 33 (or maybe a 39?) and the skeg had come off (I cannot remember the circumstances)
I was working in a small naval architecture consultancy then as junior draughtsman / tea boy, and my Boss was assigned by Moodys to investigate the claims of this chap, however I cannot remember what the final outcome was.

Re long keels, and balanced rudders hanging on transoms, one would generally think that they are not very compatible, however Chuck Paine has come up with a good compromise with his Expannie, where he has a bit of balance on the rudder, despite it being a 'traditional' rudder on the back end of a long keel - see the drawings below. Aren't those hull lines just exquisite?

 

[Laminar Flow]

I really wasn't going to get involved in this one, but the amount of nonsense that is spouted is considerable. I really do not care one iota what someone wants to cross an ocean with, that is their own and personal choice. I do note that there are some very firm beliefs held by some who have never really been offshore and by which I mean some thousands of miles away from any possible help and with it the responsibility of getting all on board to the other side.
First, it was the longkeeler crowd that were the antediluvians. Now, even a mere skeg will earn you that soubriet.

In cruising terms, the supposed loss in speed of a skeg over a spade is not only immaterial, it is undetectable. I dare anyone to quantify what this purported loss of speed would be. A very easy and scientifically supported case can be made why a rudder with skeg is actually superior in hydrodynamics, engineering, practicality and lastly safety.
Up to 10 degr. of rudder angle there is absolutely no increase in drag in a properly proportioned skeg hung rudder over a spade. Depending on the profile thickness, a spade will start loosing lift at between 11 and 14 degr. A rudder with a 25%/75% rudder/skeg arrangement will continue generating lift up to and beyond rudder angles of 40 degr. Is that important? I should think so, as a rudder has to work in the turbulence, of a hull, keel, the prop and closer to the disturbed surface water, particularly in a light boat. Turbulence will further decrease the stall angle. With a 25/75% proportion the load is, in regards to the pressure point. on the skeg, which can easily be engineered to withstand any load requirement plus a healthy safety margin.

There is absolutely no doubt that something in the way to stop some nasty bit flotsam of hitting the, arguably most important bit of kit sticking out below the hull, is a good thing. The disconcerting amount of large floating debris I encountered on my last Pacific crossing was a good reminder of that.

I wouldn't be surprised if the lack of skegs these days has more to do with the fact that it is easier and quicker to mold a hull without any bits sticking out and difficult to get at corners.

Twin rudders have nothing to do with redundancy. They are there to control an inherently unbalanced hull and they are even more vulnerable than a central spade. It should also be noted that Boreal did not choose this setup, but went for a rather short spade (and easily managed loading) and a honking big skeg ahead of it. God, I wonder why?

 

[Buck Turgidson]

I really wasn't going to get involved in this one, but the amount of nonsense that is spouted is considerable. I really do not care one iota what someone wants to cross an ocean with, that is their own and personal choice. I do note that there are some very firm beliefs held by some who have never really been offshore and by which I mean some thousands of miles away from any possible help and with it the responsibility of getting all on board to the other side.
First, it was the longkeeler crowd that were the antediluvians. Now, even a mere skeg will earn you that soubriet.

In cruising terms, the supposed loss in speed of a skeg over a spade is not only immaterial, it is undetectable. I dare anyone to quantify what this purported loss of speed would be. A very easy and scientifically supported case can be made why a rudder with skeg is actually superior in hydrodynamics, engineering, practicality and lastly safety.
Up to 10 degr. of rudder angle there is absolutely no increase in drag in a properly proportioned skeg hung rudder over a spade. Depending on the profile thickness, a spade will start loosing lift at between 11 and 14 degr. A rudder with a 25%/75% rudder/skeg arrangement will continue generating lift up to and beyond rudder angles of 40 degr. Is that important? I should think so, as a rudder has to work in the turbulence, of a hull, keel, the prop and closer to the disturbed surface water, particularly in a light boat. Turbulence will further decrease the stall angle. With a 25/75% proportion the load is, in regards to the pressure point. on the skeg, which can easily be engineered to withstand any load requirement plus a healthy safety margin.

There is absolutely no doubt that something in the way to stop some nasty bit flotsam of hitting the, arguably most important bit of kit sticking out below the hull, is a good thing. The disconcerting amount of large floating debris I encountered on my last Pacific crossing was a good reminder of that.

I wouldn't be surprised if the lack of skegs these days has more to do with the fact that it is easier and quicker to mold a hull without any bits sticking out and difficult to get at corners.

Twin rudders have nothing to do with redundancy. They are there to control an inherently unbalanced hull and they are even more vulnerable than a central spade. It should also be noted that Boreal did not choose this setup, but went for a rather short spade (and easily managed loading) and a honking big skeg ahead of it. God, I wonder why?

Show me two examples of a 25/75 skegRudder combination please?

And don't talk rudder angle if you mean AoA.

 

[Laminar Flow]

A solid skeg behind a fin keel is a lever attached to, or part of, the hull which when subjected to enough force may breach the integrity of the hull, rather than snap off at the main bearing like a spade.

Well, so is a fin keel and I'm sure you would be happy to assure me that they are perfectly safe as well.
One point not mentioned here is that it has happened that on impact a spade not only may jamb against the hull, but on occasion, the sharp trailing edge has breached the hull.

As to the rest: No boat is safe from wilful idiocy or operator error.

 

[Laminar Flow]

Show me two examples of a 25/75 skegRudder combination please?

And don't talk rudder angle if you mean AoA.

Pierre Gutelle, The Design of Sailing Yachts, page 184, also see fig. VII 26; 27 and 28.

 

[TernVI]

. Aren't those hull lines just exquisite?

No.
It looks kind of porky. A lot of volume there, squeezed into a waterline which is very short for the overall size of the thing.
The profile of the thing is kind of 1910 design, but it's gone to fat.
And that rudder will excel at catching lobster pots!
On the positive side, the keel will be invulnerable to high speed groundings, because the boat will be dog slow.

 

[Buck Turgidson]

Pierre Gutelle, The Design of Sailing Yachts, page 184, also see fig. VII 26; 27 and 28.

Actual yachts.

 

[Laminar Flow]

Show me two examples of a 25/75 skegRudder combination please?

And don't talk rudder angle if you mean AoA.

In the case of a boat being over pressed or in a "death roll" going down hill and requiring strong correction, AoA and rudder angle may very well be the same.

 

[Laminar Flow]

Actual yachts.

The Types of Sailboat Rudders
liveabout.com

Kraken 50. Really? There are plenty more where that came from.

 

[Buck Turgidson]

The Types of Sailboat Rudders
liveabout.com
View attachment 98323
Kraken 50. Really? There are plenty more where that came from.

zero keel !!!!! hahahahahaha..........

 

[Laminar Flow]

I remember in the late 80's there was a chap advertising in the classified ads of YM, looking for other Moody owners who might have been in the same boat as him - seems like he had a Moody 33 (or maybe a 39?) and the skeg had come off (I cannot remember the circumstances)
I was working in a small naval architecture consultancy then as junior draughtsman / tea boy, and my Boss was assigned by Moodys to investigate the claims of this chap, however I cannot remember what the final outcome was.

Re long keels, and balanced rudders hanging on transoms, one would generally think that they are not very compatible, however Chuck Paine has come up with a good compromise with his Expannie, where he has a bit of balance on the rudder, despite it being a 'traditional' rudder on the back end of a long keel - see the drawings below. Aren't those hull lines just exquisite?

View attachment 98307


View attachment 98309


View attachment 98308

Re Mr. Tern's comments : I think the example posted is certainly pretty in a classic sort of way and Chuck Paine is not exactly known for designing a slouch either. Whether that may agree with personal taste is irrelevant; I'm pretty sure "the sea, she don't care either".

In cruising terms, i.e. loaded for the job, I doubt there would be any appreciable difference in speed between it and a JenBenBav of the same length and with the same amount of inevitable junk on board, given an equal SA/Displ. ratio.
Of course one could argue which would be less prone to slamming and more comfortable in a seaway.
As usual, the discussions here are more about semantics and at the very best, empirical, somewhere along the lines: my uncle's cousin, twice removed, his friend ... hit some rock and sunk ... etc.
What I miss is a clear quantified statement whether x is faster than y under the same conditions and if so, by how much exactly and what precisely I have to give up to achieve that in terms of comfort, safety, peace of mind (whether that be based in reality or not) as well as sheer plain practicality.

Much like car design and styling, boat design is equally subject to fashion and fads. And, much like cars, some of the features don't have much to do with practical reality or the needs of the owners and a few more have to do with ease of construction and production efficiency.

 

[Laminar Flow]

zero keel !!!!! hahahahahaha..........

Who was talking about zero keel ?????????? The Kraken 50 appears to have perfectly viable keel.

 

[Buck Turgidson]

back to the OP:

Folkboat or Vertue fit the brief. As does my Twister. (Which also has a "zero keel" )

For Laminar Flow, I asked for 2. I don't think they've built 2 Krakon 50s yet so you need another 25/75 skeg/Rudder combo. Of course putting the hinge at 25% chord doesn't exactly promote laminar flow which is why you're struggling to find examples of your optimum combo.

Much easier to find transom hung balanced blades that kick up. Best Hydro and best impact mitigation. But you knew that right?

 

[Baggywrinkle]

Don't want to deprive skeg lovers of their comfort blankets, but just for balance ....

Overboard in the Atlantic – how I fixed a broken rudder - Practical Boat Owner

When we lifted EA out and used a grinder to take a closer look at the skeg, we saw a crack. We never believed something like this could happen because it’s such a strong boat....

.......Over the two weeks that we’d been steering the bolt must have worked free a little. It wasn’t so noticeable during the small movements, but when there was a big swell, and we had the maximum angle on the rudder, the forward fastening worked loose and this then prevented the rudder blade from being able to move past the skeg shoe.

 

[john_morris_uk]

One point not mentioned here is that it has happened that on impact a spade not only may jamb against the hull, but on occasion, the sharp trailing edge has breached the hull.

Reference please. I’ve never heard of such an incident and im very interested to learn about the boat etc.

(I suspect the aft end of our boat would be ripped off before the trailing edge of the rudder pierced our hull.)

 

[geem]

Actual yachts.

Heres one

 

[TernVI]

Heres oneView attachment 98345

That's interesting.
I can't read everything on the plan, but it looks like a fairly strong rudder with some little fairing ahead of it.
The skeg seems to be lightly engineered and not massivley attached to the hull?
What is the background of this?