Pilothouse Variations -- Boreal

[markpierce]

A skeg protecting propeller and rudder would be appreciated.

[Dockhead]

So many interesting responses! Sorry to have been offline -- I was at sea. Nonstop from Copenhagen to the Stockholm Archipelago, a half-circumnavigation of Sweden including all of the South and Southeastern coasts and a bit of the Western.


Yes, the Boreal is interesting to me because of the doghouse/pilothouse approach, and the way it is constructed. It has a few features which are not good for me, but the hull form is NOT a wedgie -- it has a slightly raked stem, flared topsides, strongly flared topsides aft, with the waterline strongly tapered aft -- so much closer to my present boat, than to a Hanse, for example. Bottom still a little flat for my taste, and the rig is too big.

Getting back to the general question of hull form, which we drifted on to -- I am looking for a long boat with modest beam (not ultra narrow), reasonably light (160-180) but not ultra light. The main thing is that the hull should be easily driven through the water in order to allow the use of a compact and very low windage rig. The low, small, and very low windage rig will make it easier to get the boat upwind and make the boat easier to sail, especially in bad weather and long passages. That's the type of "sailing efficiency" I'm looking for -- and the holy grail here is low windage. The "wedgie" approach with lots of form stability and a huge rig is just the opposite of what I need for these conditions up here. Surfing ability is unneeded and is probably even a negative (as someone said).

The other thing the hull should provide is minimal pounding, and dry decks. I'm willing to live with some pitching and with the slight loss of speed potential from having flared bows because I don't want the bows stuffed into the backs of waves, and I don't want green water sweeping the decks in winter storms.

Dashew's Sundeers are probably closest in hull form to what I have in mind -- the accommodation of a 45 footer in a 65 foot boat with the beam of a 45 footer but with a 65 foot waterline -- bravo. He achieved what I want to achieve, which is very high practical, effortless short-handed passage speeds (unsurpassed AFAIK), with a short, small, modest rig, and even very modest draft. All that modesty and wisdom and subtlety in the various design compromises are qualities which go right over some people's heads, of course, but the best sea boats are always like that, and not like Lamborghinis. The most important quality of a naval architect is how well he can juggle all these compromises, not ambitious, aggressive, or in your face he is -- ugh.

Just a couple of compromises Dashew made which I would do differently, however, is that he gave up some reserve buoyancy in the bows for the last possible bit of waterline length, with the result that the Sundeers do not have the driest decks in the world, and I don't like the aft cockpit, and lack of any dinghy storage.

As to rudders -- another hard trade-off, but after reflection, full skeg rudders are not for me. The rudder is a wing which is no less important than the sails or the keel, and you pay dearly for compromises in hydrodynamics there. I'll have a massively overbuilt spade rudder (again, a la Dashew), but it will not be blade thin and it will be quite a bit shorter than the keel, unlike what you see on race boats -- so again -- best practicably achievable hydrodynamics, but not to the extent that it's thin as a toothpick and as deep as the keel, just waiting to be snapped off on a rock.


As to the original topic - pilothouses -- I love the Boreal approach, but after reflection I think I am going more to the SWL approach and create a space where the crew can live at anchor or in port in bad weather as well as good, and watch the world go by.

I have an idea that a pilothouse, even one designed to accommodate these functions, need not cause all that much windage if it is properly designed by someone who really understands the aerodynamics, and maybe even using a wind tunnel and models. For example, it used to be thought that open cars without the superstructure on top were faster, but once car designers started to understand something about aerodynamics, it was realized that an aerodynamic coupe produces much less drag, than an open cockpit. Despite all the ludicrous advertising hype about the "state of the art" and all that other carp, pleasure boat design is still in the stone age, driven 95% by accomodation, cheapness, and looking cool according to the fashion of the moment, and I would not be surprised if boat designers haven't gotten too far in studying how to create a really aerodynamic pilothouse.

[TheThunderbird]

DH
You need a relatively long boat, with empty ends, for good steering and power without over-canvassing the rig (staysail and Yankee?)

Like was Gipsy Moth IV, but with a bit higher bulkhead to keep deck dry

I'd also opt for a moderate (1' high) hull profile, In Connecting a half skeg to Finn keel ballast, to be quite important (>40%)

I'd also opt for water ballast (not to extreme consequences, though).

On an Alu deck, you could think of detachable components for disassembling the dog house

Btw, I have no wind tunnel, am no NA either.

:-)

[Dockhead]

Originally Posted by TheThunderbird

DH
You need a relatively long boat, with empty ends, for good steering and power without over-canvassing the rig (staysail and Yankee?)

Like was Gipsy Moth IV, but with a bit higher bulkhead to keep deck dry

I'd also opt for a moderate (1' high) hull profile, In Connecting a half skeg to Finn keel ballast, to be quite important (>40%)

I'd also opt for water ballast (not to extreme consequences, though).

On an Alu deck, you could think of detachable components for disassembling the dog house

Btw, I have no wind tunnel, am no NA either.

:-)

Indeed -- long, with empty ends and moderate beam. Just the ticket.

Gypsy Moth is 54' and only 10' beam -- very narrow. Sundeer is 65' with 64' waterline, and 15.1' or a bit narrower than my boat, which is 11' shorter (and almost 20' less waterline).

Sundeer proportions are about right for me, although I might make the draft a bit deeper (Sundeer <2 meters).


As to water ballast -- I had an idea today. If it's at all worth doing (depends on shape and weight distribution of the boat), then the easiest way to do it is to combine it with gray water tankage. Pump in seawater for ballast, and when not being used for that, you can use the tanks for grey water.

Right out at the max beam amidships, making a double skin. But with some really good provision for cleaning them out.

I realize there will be some problems keeping them clean, but solvable I believe.

[Kenomac]

Why don't you simply buy a Discovery 55, which is what you've been describing all along?

[reed1v]

At the other extreme is the old double ender English fishing trawler converted to sailboat. Big stand up pilothouse, comfy in all sea conditions, immense load capacity for LWL, easy to self steer, and most move at 1.3(sqrt LWL). Yes fast is fun, but for older folks, not very comfy over long sailing distances. And there is not much that can beat sitting under big awning on the long foredeck while sailing down the trades. No tight cockpits and tiny deck areas for us.

[poiu]

Originally Posted by TheThunderbird

DH
You need a relatively long boat, with empty ends, for good steering and power without over-canvassing the rig (staysail and Yankee?)

Like was Gipsy Moth IV, but with a bit higher bulkhead to keep deck dry

:-)

Gipsy Moth IV was reputedly very tender. I think in no small part because of the narrow beam. Not ideal really.

[reed1v]

Originally Posted by poiu

Gipsy Moth IV was reputedly very tender. I think in no small part because of the narrow beam. Not ideal really.

Sir Francis bemoaned the tenderness of GM4 and really did not like the way the boat sailed, but sailed it anyways. It was not only tender, but quick to do so; which peeved him to no end. But it was fast and seaworthy. Famous picture of him rounding the Horn with just a jib and some rather large seas escorting him.
It seemed a case of the designer overriding the owner's desires. Not uncommon when commissioning a new yacht.

[Polux]

Originally Posted by Snowpetrel

Polux, your understanding of the complexities of yacht design and racing rules is very simplistic. There are a number of factors in the open class rules that drive them towards wide boats, that simply are not relevant to cruising.

The real issues with Project Amazon were weight related. She was estimated to be around 19 tonnes. Far too heavy to be competitive against much lighter boats.

The ketch rig is not intrisicaly harder to handle than any other rig. In some cases it can be easier.

If you want to see how a narrow boat went ocean planet makes a better example, she placed respectably, for an older design built on a shoestring.

Absolute top speeds surfing are not a priority for most cruisers. I actually dont want boat to surf. It plays havoc with my windvane. And stresses the rudder and boat more than I am comfortable with for ocean crossing where I pay the bills for fixing any breakages.

Anyway, I think we are not going to get much more from this line of discussion than an endless repetition of the same points.

I will leave you with a video my brother made of his wide sterned sunfast 3600. It will keep you happy I am sure I am keen to see how he goes in the RNI two handed race.

He likes the boat but says she is a bit sticky in the light. He is a damned good sailer and makes it look easy

https://m.youtube.com/user/BooBooNZ?

This is a 35 foot canting keeler in a bit of wind.

Very nice videos but those two are racing boats, nice ones I would say. I am talking and posting about cruising boats.

The main difference are not only the interior, that should be a good cruising one, but mostly the easiness to handle the boat solo.

Boats relatively narrow (moderated beam if you wanted), like those two, can be faster than beamier type of solo boats, the same type of hulls used in some cruising boats, but they are much less forgiven and need a crew to go fast.

The beamier type of solo boats is designed to go fast on autopilot and that is a completely different story in what regards easiness. Not so fast in absolute terms but faster and much less demanding with a solo or less experienced sailor. That is why that type of hulls is used on cruising boats.

[Polux]

Originally Posted by Kenomac

Why don't you simply buy a Discovery 55, which is what you've been describing all along?

I hope not. That is an ugly boat with an outdated hull (16 years old). They updated already the design on the 48 but the 55 is just a MKII





The 48:




Regarding British medium displacement boats the Gunfleet 58 is a lot nicer and has a contemporary hull design:





It has not, on its standard version, a deck saloon, or pilot house, but on this range of price (about 2 millions) they will customize the boat to the client desires, with some small extra cost.

[Kenomac]

Polux,

I agree with you on the Gunfleet; we saw it at the boat show and it was excellent. But my comment was directed to Dockhead, he keeps describing a Discovery 55 with his wish list. A few of his latest posts bordered on describing a MacGregor 65.

[TheThunderbird]

A grey water tank with long intake hoses is quite undesirable.

The idea of having suspicious material circulating around is quite unappealing :-P

Please consider that water ballast will make for a not-so-narrow beam amidship, as they are usually positioned there, where most needed.

[TheThunderbird]

Originally Posted by reed1v

Sir Francis bemoaned the tenderness of GM4 and really did not like the way the boat sailed, but sailed it anyways. It was not only tender, but quick to do so; which peeved him to no end. But it was fast and seaworthy. Famous picture of him rounding the Horn with just a jib and some rather large seas escorting him.
It seemed a case of the designer overriding the owner's desires. Not uncommon when commissioning a new yacht.

You mean tender for heeling, maybe.

It was prone to tilt 30° easily, but then it stayed strong.

Leaving NZ it remained 60° down on board. For one full week :-)

Uncomfortable, but Illingworth had been asked for a record-breaking design, and he did it.

I also remember some bow section being lengthened, for better tacking and nailing.... but memory fails..

[Polux]

Originally Posted by reed1v

Holding LWL constant, the wider the beam, the higher the boat will ride, the lessening of windward ability, and the stiffer the boat(may or may not be a good thing). Keeping LWL constant and increasing the load factor, increasing the beam will allow greater load carrying, but at less ultimate stability and comfort.
,,,,.

That is a lot of generalization. A beamy boat if light, as it is generally the case, has a very small beam at waterline and that is what counts for upwind performance, that, very fine entries and a big draft.

Take for instance the max beam of an Open 60 and the beam at waterline that you can see on these images:





You forgot to mention that maintaining LWL and B/D ratio constant, the beamier boat will have a lot more stability (needing a bigger breaking wave to capsize it) and regarding ultimate stability what you say it is not true. The ultimate stability depends basically on the position of a boat CG, not on the beam of the boat.

Normally being all stability better, the ultimate stability would be better too on a beamy boat, meaning that at 70º, 80º or 90º the beamier boat will be making a lot more force to right itself up (bigger RM) and for the same B/D ratio the AVS should not be very different.

Take for instance the stability curve of the new Dehler 34 (last post on my blog), a very beamy boat with an excellent stability curve, an AVS near 140. Just for comparison effects a Vaillant 40 has 125º, a Sabre 402 114º. Since we talked about we can add also the one of the cruising Pogo 12.50, with an AVS near 125º.

Dehler 34:



Vaillant 40 and Sabre 402:





Pogo 12.50:




The image of the Pogo 12.50 going upwind is a good example of the difference between the max beam and the beam at waterline: Notice even with small heel how much of the hull is out of the water.

Note that the 114ºAVS of the Sabre is not really bad. Lot's of old boats have much lower AVS (not all), before RCD have been increasing standards.

[Polux]

Originally Posted by Dockhead

...

As to water ballast -- I had an idea today. If it's at all worth doing (depends on shape and weight distribution of the boat), then the easiest way to do it is to combine it with gray water tankage. Pump in seawater for ballast, and when not being used for that, you can use the tanks for grey water.

Right out at the max beam amidships, making a double skin. But with some really good provision for cleaning them out.

I realize there will be some problems keeping them clean, but solvable I believe.

Hum, I have changed all my **** tubes. They became permeable with time (not much time) and start letting the odor pass. I believe that solution would only increase the problem unless some kind of light metal tubes were used (it was explained to me by an expert that they are the only ones that last in what regards keeping the smell out.

But regarding water ballast it really only makes sense on a beamy boat were the effect is maximized. On a narrow boat they will have a much more limited effect and probably would not deserve the effort.