First came from Robert: -
Ross- I'm following Whimbrel developments with keen interest. I have long considered Jim Michalak's Frolic2 based on Gary B's Everglades Challenge success with the design. I live 30 minutes from the start of the EC and hope to enter in the near future.
My only concern thus far is the length of the cockpit and cabin floor. Your drawings show the opportunity for one to stretch out in each spot, but I am 6' 4" tall. Can you share approximate lengths of those spaces?
The cabin and cockpit arrangement on Whimbrel owes much to the brilliant design concept that Phil Bolger employed in his Micro. By that I refer to the cabin space and the cockpit "overlapping" longitudinally so that a person sitting or lying down at the forward end of the cockpit is actually positioned above the legs of a reclining person in the cuddy-cabin - in much the same way as happens with quarter berths in larger cruisers.
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| You can see here how the accommodation spaces overlap |
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| Periwinkle on launching day showing the self-draining outboard well. The camera had a wide-angle lens making the well look a bit larger than it is in the flesh |
Back to Robert's question...
The longitudinal space available in the cockpit, measured between the main bulkhead and the forward bulkhead of the aft deck i.e. the total length of uninterrupted sleeping/sitting space is 6'ft 8-9/16". In the cabin, there is 6' 6-5/8" of bunk-space with an additional 11-1/8" of clear space between the forward end of the bunk and the forward bulkhead of the cabin giving 7' 5-3/4" total. There are compartments leading forward from the end of the cabin for stowage - two accessible from in the cabin, and two from on the deck which drain overboard - used for anchors etc.
Another comment came from Wayne Jorgensen: -
Ross
another quick question re Whimbrel's pram bow. I've spent some time watching Sabots trying to punch into a chop- to the detriment of their speed and handling. Wont there be the same issues with Whimbrel's near vertical pram bow? Scandinavian prams lift their bows much higher so this is not really an issue with them but then they are not live aboard cruisers either.
Regards
Wayne
I agonised over this very matter when I was doing the initial hull modelling. The competing factors were;
- maximum volume and reserve buoyancy on a given LOA;
- maximum speed (in smooth water) from a given LOA;
- lack of annoying wavelet noise under the bow while at anchor;
- a chine-line (in body-plan view i.e. viewed from bow and stern) which would produce the minimum cross-flow and eddy-making.
It was Phil Bolger who pointed out that a vertical transom gives the maximum waterline length for a given length on deck. He also said that a vertical transom can dig into waves and throw spray - but he then went on to say that by raking the stem forward it would reduce the spray and the digging tendency, but would make the boat longer. So why not pull the waterline length out to match the new length on deck with a vertical transom and get even better performance? Here is one of his several comments on the subject: -
"Raked transoms make a faster boat less badly stopped by waves if they are raked out from the given bottom length, but in that case the boat would be better still if the waterline were carried out to plumb transoms at the new overall length...." (Boats with an Open Mind, International Marine 1994)
What I could say to make myself feel justified is to say that Whimbrel was a 17' boat with a nicely raked bow transom, but I pulled out the bottom length to produce more volume and speed...... But no, I drew what I thought was a good compromise for a fellow who wanted a maximum LOA of 17'. The customer went overseas and had to cancel the design, but I was so taken with it by that time that I decided to finish her off as a stock plan. That is why it has taken so long for me to finish, as I only work on the drawings occasionally.
Phil Bolger sometimes said or wrote the strangest things. I have to point out the fact that you don't make the boat faster in any practical sense by drawing out the waterlines to the full LOA, leaving the boat just whacked off in a plumb scow bow that touches the water, or nearly so, at rest. What you do is create a monster that will misbehave in the slightest seaway and almost any wind.
ReplyDeleteI very much like the concept Ross is promoting in Whimbrel. I've admired the design since first seeing it almost a year ago, but I certainly would make the boat eighteen inches or two feet longer at the forward end without changing anything else, getting that scow bow up, well out of the water and raked a bit more. Just imagine for a moment the danger of broaching on a downwind point of sail with following sea and opposing chop set up by a river's outflow agains tide and wind, with that scow bow slamming into the chop and the following waves trying to push your stern ends around. Those are conditions one can expect to encounter routinely when entering many estuaries, let alone the conditions encountered while struggling in a squall or making for home in suddenly rising stormy weather.
Living as I have for many years in Asia, I have had the opportunity to look closely at a variety of scow bowed Asian sailing and motoring craft. Generally, you find that either the bow transom is raised well above the LWL or it is raked well aft. Some are built with a profile like a garvey, that is, raked and rounded, cross planked, to recede as they approach the LWL. In most cases, some compromise has been made in order to reduce the impact of the transom or scow bow against wave and chop.
Bolger was a brilliant designer, but he had a tendency to paint himself into the damnedest corners, and he was stubborn enough to stick to his pet theses no matter what. You have to admire most of his work, perhaps even his stubbornness when he was right, but you'd better take some of his philosophizing with a grain of salt. Boats move through a constantly troubled and dynamic pair of fluids that make up one of the least forgiving environments on our planet. You flout at your own risk the limits and dangers they pose.
Rick Hayhoe
No corners painted by Bolger here - even on those square boats! ;-)
ReplyDeleteWhat's not to understand? Drawing the bottom (and waterline) out to be as long as the deck of an otherwise raked ends hull makes for a narrower stern and narrower bow at the waterline. The narrower entry is less stopped by waves and less wet. The drawn out waterline on the same beam has higher theoretical speed. Importantly (never forget the several intricate ways Bolger stressed the virtues of "shallow", this is but one) it also has less draft, and so less resistance, thereby being more likely to achieve or exceed that theoretical speed.
It's in no way all about the bottom though. What is often passed by in what Bolger said is that it's the decks that raise hull cog, and Bolger viewed decks, rightly, as a penalty. Other considerations not withstanding, he may just have stuck to raked ends, clipper bows, and such, if he'd been able to design decks of weightless unobtainium. As it is, plumb ends (and sides) impose a smaller deck weight penalty on a given bottom, or on stability, or on ability to stand up to sail, or on overall performance.
Flow on efficiencies there, which may also continue to run right into the pocket.
No corners then, painted or otherwise, rather Bolger's genious yet again seen remarkably squaring a circle unlooked for. A virtuous circle spiralling on with yet more angles to each turn.
Graeme
There's a hundred year old essay by Prof William Lyon Phelps about the poet Robert Browning, born 1812, which in part might well be about the Phillip C Bolger original genius type.
ReplyDelete"...Authors are compelled to write for the market, whether they like it or not, otherwise their work can not appear in print. ...With one exception, the law of supply and demand determines the metrical shape of the poet's frenzy, and the prose mould of the philosopher's ideas.
The exception is so rare that it establishes the rule. The exception is Genius... And even Genius often follows the market--it takes the prevailing literary fashion, and adapts itself to the form in vogue in a more excellent way. Such genius--the Genius for Adaptation--never has to wait long for recognition, simply because it supplies a keen popular demand. Such a genius was Shakespeare: such a genius was Pope: such a genius was Scott: such a genius was Byron: such a genius was Tennyson. But the true exception to the great economic law is seen in the Man of Original Genius, who cares not at all for the fashion except perhaps to destroy it. This man is outside the law of supply and demand,
because he supplies no demand, and there exists no demand for him. He therefore has to create the demand as well as the supply. Such a man in Music was Wagner: such a man in Drama was Ibsen: such a man in Poetry was Browning.
...They had to wait long for recognition, because nobody was looking for them, nobody wanted them. There was no demand for Wagner's music--but there is now, and he made it... The reason why the public does not immediately recognise the greatness of a work of original genius, is because the public at first--if it notices the thing at all--apprehends not its greatness, but its strangeness. It is so unlike the thing the public is seeking, that it seems grotesque or absurd--many indeed declare that it is exactly the opposite of what it professes to be. ...many men of learning and culture have been loudly proclaiming that Browning, whatever he was, was not a poet; he was ingenious, he was thoughtful, a philosopher, if you like, but surely no poet...
...One of the most admirable things about Browning's admirable career as poet and man is that he wrote not to please the critics, as Tennyson often did, not to please the crowd, as the vast horde of ephemeral writers do, but to please himself. The critics and the crowd professed that they could not understand him; but he had no difficulty in understanding them. He knew exactly what they wanted, and declined to supply it. Instead of giving them what he thought
they wanted, he gave them what he thought they needed. That
illustrates the difference between the literary caterer and the literary master.
In the case of a man of original genius, the first evidence of approaching fame is seen in the dust raised by contempt, scorn, ridicule, and various forms of angry resistance from those who will ultimately be converts. People resist him as they resist the Gospel. He comes unto his own, and his own receive him not. The so-called reading public have the stupid cruelty of schoolboys, who will not tolerate on the part of any newcomer the slightest divergence in dress, manners, or conversation from the established standard. Conformity is king; for schoolboys are the most conservative mass of inertia that can be found anywhere on earth. And they are thorough masters of ridicule--the most powerful weapon known to humanity. But as in schoolboy circles the ostracising laughter is sometimes a sign that a really original boy has made his appearance, so the unthinking opposition of the conventional army of readers is occasionally a proof that the new man has made a powerful impression which can not be shaken off..."
http://www.fullbooks.com/Robert-Browning-How-To-Know-Him1.html
I rudely hacked more food for thought from this genius passage to fit it in. Apologies.
Graeme
graemes4-boatstuff@yahoo.com.au
No corners painted by Bolger here - even on those square boats! ;-)
ReplyDeleteWhat's not to understand? Drawing the bottom (and waterline) out to be as long as the deck of an otherwise raked ends hull makes for a narrower stern and narrower bow at the waterline. The finer entry is less stopped by waves and less wet. The drawn out waterline on the same beam has higher theoretical speed. Importantly (never forget the several intricate ways Bolger stressed the virtues of "shallow", this is but one) it also has less draft, and so less resistance, thereby being more likely to achieve or exceed that theoretical speed.
It is in no way all about the bottom though. What is often passed by in what Bolger said is that it's the decks that raise hull cog, and Bolger viewed decks, rightly, as a penalty. Other considerations not withstanding, he may just have stuck to raked ends, clipper bows, and such, if he'd been able to design decks of weightless unobtainium. As it is, plumb ends (and sides) impose a smaller deck weight penalty on a given bottom, or on stability, or on ability to stand up to sail, or on overall performance.
Flow on efficiencies there, which may also continue to run right into the pocket.
No corners then, painted or otherwise, rather Bolger's genious yet again seen remarkably squaring a circle unlooked for. A virtuous circle spiralling on with yet more angles round each turn.
Graeme
Ross,
ReplyDeleteIt seems you are going to take a much needed break from design/building to maintain your own fleet and perhaps build a canoe yawl for your own use. Just curious if a whimbrel plans might be completed at some point? I forgot whether it was an experimental or commissioned design.
Additionally, we shared correspondence regarding stitch and glue construction. What do you think about the CAD designed s-n-g method allowing designs to closely follow round bilge profiles using several pre-shaped panels per side?
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