Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 16-05-2016, 12:52   #196
Registered User
 
Cadence's Avatar

Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 6,063
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by barnakiel View Post
It is getting somewhat monotonous, that 'reserve' hum.

Why assume there is any reserve required? E.g. the plumb (or, OMG, reverse!!!) bow can be matched with very narrow entry, or not, built in carbon, or not, matched with tall topsides, or not ...

There is definitely nothing wrong with plumb or reverse bows. We must look at boats as wholes and then we can say that this or that style of the bow works (or does not) on this specific boat.

Let alone that those expensive big beautiful PLUMB bows are most often owned and driven by retired Madame et Messieur from Paris, FR. They will love their petit 50'+ bateau very much and are not likely to push that beautiful plumb bow under l'eau. Jamais! The assurance would never pay the damages!

My boat has an errrr plumb (well, 'nearly') bow and she sails great. I do not see any shortcomings in this specific execution (A.D. 1969!). I do not see any need for 'reserve' anything here.

Tzu Hang burried her bow twice (or was it three times?) up to the point of capsizing over the bow ... neither plumb nor lacking displacement in the bow. How odd.

If you are burying her bow in the sea that's maybe you have specified to big an engine for your boat. Sail more. Speculate less.

b.
Even well known naval architects will throw stones a one another. One wrote me he wouldn't hold it against me that I had met another. It may have been in jest or not? I feel sure nothing meant in malice, just two different opinions.
__________________

__________________
Cadence is offline   Reply With Quote
Old 16-05-2016, 14:10   #197
Registered User

Join Date: Oct 2008
Location: San Diego, CA
Boat: Beneteau Oceanis 38.1
Posts: 244
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by Dockhead View Post
But this is how a reverse bow tends to behave:

Attachment 124436

That's the "wave piercing" effect of a reverse bow in action, when you definitely don't want it, and that's not even a difficult sea condition.
Certainly reverse bows will tend to do that. But that is how all boats with too little buoyancy in the bow vs the balance of the overall boat tend to behave when driven too hard downwind in a big seaway. IMS boats with normal destroyer bows and later plumb bows has this tendency as well because they were not well balanced fore/aft in this regard. They had a lot of buoyancy aft, not enough forward, and a keel that was placed rather forward to balance the rig location, all of which was the "optimal" set of parameters to meet the IMS formula rule at the time. Seeing the entire crew hanging off the back of the boat while going downwind was a common sight for a while in the 90's. It was dangerous as hell BTW, especially when coupled with the noodly rigs of the time - stuff the bow and if you didn't pitch-pole you'd rip the rig off the boat, with everyone standing next to the backstay that was just being torn apart.
__________________

__________________
gjorgensen is offline   Reply With Quote
Old 16-05-2016, 14:41   #198
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 5,765
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by Dockhead View Post
No, the comparison is exactly correct -- same LWL, same LOA.


Just look at LOA of this boat!!!! most would say that is a 22ft boat (6.5m) but they are obviously wrong

Most of the boats with big poles have a simple way to take them in (due to marina charges. The anchor stand is just a small part of the pole structure.

...
Quote:
Originally Posted by Dockhead View Post
However, they have a couple of disadvantages also:

1. Less resistance to immersion -- and no progressivity in this resistance.

2. Problems with anchors and some deck gear which often make bowsprits necessary.
As I have explained extensively the first point is plain wrong, in fact it is the opposite, if we consider hull length that is the main length in any sailboat.

You are right regarding the second point and they demand an anchor stand longer but with the need of poles due to the generalization of gennakers as a cruising sail, that is not a problem.
Polux is offline   Reply With Quote
Old 16-05-2016, 15:14   #199
Registered User
 
funjohnson's Avatar

Join Date: Mar 2010
Location: Currently Indiantown FL
Boat: 37' aluminum pilothouse "Elements"
Posts: 1,847
Re: Pilothouse Variations -- Boreal

Polux, you're right. The extra bowsprit is not a part of the length on deck. I'm not sure what people are missing....a westsail 32 is called that because it is 32' on deck, but much larger overall. If the westsail 32 was a plumb bow, it still would be 32' on deck with the same bowsprit and overall length, but that added 3' waterline of a plumb bow would add to resistance and buoyancy. A plumb bow can still have hull flare which gives the progressive resistance everyone is talking about.

Look at the photos posted of the racers bow.... It's not straight up without flare. Here is where the resistance comes from along with the added already immersed waterline.

Sent from my LG-V410 using Cruisers Sailing Forum mobile app
__________________
MJSailing.com - Written Blog
Youtube MJ sailing - Vlog
funjohnson is offline   Reply With Quote
Old 16-05-2016, 15:18   #200
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 5,765
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by Dockhead View Post
I agree with all of this, except only one thing -- there is no such thing as a "modern hull". The design tradeoffs have not disappeared.
...
No, there is not a modern hull (I prefer contemporary or to the state of the art) but there are several modern hulls, from different sailing programs. They share some common characteristics and some differences that can be quite big.

When I talk about modern hulls I mean they are contemporary in design (from different types, as opposed to old designed hulls, meaning hulls that the same designer for the same sail function would have designed 30 years ago but that today would consider obsolete.

The contemporary one is just a gradually improved state of the art version of the old one incorporating all the improvements that sail design development had brought in what concerns the possibility to design a faster, and better sailboat, not only faster but with a better and more comfortable interior.

Let's take for instance a very conservative sailboat brand, Halberg Rassy that has been designed on the last decades by the same design cabinet, German Frers.

German Frers brought contemporary design to Halberg Rassy. Just compare one of the firs H&R designed by them, the 39 (1990) with one of the last designs from the previous designer (Olle Enderlein), the 46 from 1982:





It is not by accident that Olle Enderlein is just a footnote regarding the great designers of the last decades of the XX century while German Frers is a main reference.

So, after 34 years let's have a look of what German Frers is designing now for H &R, the last design, the 44:


Yes, it is still a conservative design for a conservative brand with conservative clients, but a modern design. Certainly German Frers would not dream to purpose today a design along the lines of the 39 (that was a modern design on its days) simply because it would be bad naval Architecture, an obsolete design.

I let you find the differences between those designs and what makes the last one modern and the others obsolete.

Of course, if H&R was a different boat with a different program, another type of hull and NA solutions would be found but certainly none of them obsolete, at least if it was designed by German Frers.

That has nothing to do with magazines or fashion but with the evolution of Yacht Naval Architecture and the (better) solutions it can find today for different boat programs.
Polux is offline   Reply With Quote
Old 16-05-2016, 15:21   #201
Registered User
 
hoppy's Avatar

Join Date: Sep 2009
Location: Melbourne, Australia
Boat: Jeanneau Sun Odyssey 40
Posts: 2,842
Re: Pilothouse Variations -- Boreal

If you want a bow with plenty of buoyancy, you could always copy the design of some mini transat yachts



__________________
S/Y Jessabbé http://www.jessabbe.com/
hoppy is offline   Reply With Quote
Old 17-05-2016, 12:48   #202
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch
Posts: 1,828
Images: 2
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by funjohnson View Post
Polux, you're right. The extra bowsprit is not a part of the length on deck. I'm not sure what people are missing....a westsail 32 is called that because it is 32' on deck, but much larger overall. If the westsail 32 was a plumb bow, it still would be 32' on deck with the same bowsprit and overall length, but that added 3' waterline of a plumb bow would add to resistance and buoyancy. A plumb bow can still have hull flare which gives the progressive resistance everyone is talking about.
Dufour 350 Grand'Large is 33' so your point is not valid...
__________________
TeddyDiver is offline   Reply With Quote
Old 17-05-2016, 14:30   #203
Registered User

Join Date: Feb 2011
Posts: 2,105
Re: Pilothouse Variations -- Boreal

In the old days, boats were measured on the waterline-lwl. Then in the 60s boats began to be measured on deck-lod. Marketing wizs nowadays are talking about boats in terms of length overall--loa. Speed and capacity really relate to lwl.

None of which have to do with reserve buoyancy to any degree. A plumb bow with a significant rise above the water has as much buoyancy as a clipper bow with less rise. Or you could just sail with a big air bag tied to the bow.
__________________
reed1v is offline   Reply With Quote
Old 17-05-2016, 14:41   #204
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch
Posts: 1,828
Images: 2
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by Polux View Post
That has nothing to do with magazines or fashion but with the evolution of Yacht Naval Architecture and the (better) solutions it can find today for different boat programs.
Nope, it's about being price competive, key being more cabin space for the beaver (Sorry couldn't help myself)
__________________
TeddyDiver is offline   Reply With Quote
Old 17-05-2016, 14:54   #205
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 19,752
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by Polux View Post
No, there is not a modern hull (I prefer contemporary or to the state of the art) but there are several modern hulls, from different sailing programs. They share some common characteristics and some differences that can be quite big.

When I talk about modern hulls I mean they are contemporary in design (from different types, as opposed to old designed hulls, meaning hulls that the same designer for the same sail function would have designed 30 years ago but that today would consider obsolete.

The contemporary one is just a gradually improved state of the art version of the old one incorporating all the improvements that sail design development had brought in what concerns the possibility to design a faster, and better sailboat, not only faster but with a better and more comfortable interior.

Let's take for instance a very conservative sailboat brand, Halberg Rassy that has been designed on the last decades by the same design cabinet, German Frers.

German Frers brought contemporary design to Halberg Rassy. Just compare one of the firs H&R designed by them, the 39 (1990) with one of the last designs from the previous designer (Olle Enderlein), the 46 from 1982:





It is not by accident that Olle Enderlein is just a footnote regarding the great designers of the last decades of the XX century while German Frers is a main reference.

So, after 34 years let's have a look of what German Frers is designing now for H &R, the last design, the 44:


Yes, it is still a conservative design for a conservative brand with conservative clients, but a modern design. Certainly German Frers would not dream to purpose today a design along the lines of the 39 (that was a modern design on its days) simply because it would be bad naval Architecture, an obsolete design.

I let you find the differences between those designs and what makes the last one modern and the others obsolete.

Of course, if H&R was a different boat with a different program, another type of hull and NA solutions would be found but certainly none of them obsolete, at least if it was designed by German Frers.

That has nothing to do with magazines or fashion but with the evolution of Yacht Naval Architecture and the (better) solutions it can find today for different boat programs.
I'm not going to google, download, and post all the different images because everyone can easily find the images themselves.

If you look at the whole current product lines of Oyster, HR, Contest, Discovery, Hylas, and any other builder of higher end, non mass produced cruising boats, with only a few exceptions, the hull form is the same, and in fact is exactly the same as my boat, although mine was designed way back in 2000 -- moderate rake in the bow, moderately tapered aft sections, reverse counter transom quite a bit narrower than maximum beam, flared topsides, and a moderate aspect ratio, wide-based bulb keel. You see no torpedo keels, no plumb bows, no tumblehome or flat sides, no full width transom, no flat aft section.

Of course there is evolution, and boats have become longer and usually lighter, non-bulbed fin keels have disappeared right after full keels with barn door rudders.

But this "evolution" is not a straight line leading all in one direction. The wedge shaped hull with sharp plumb bow, full width transom, and flat topsides is not where the whole world is going and for very good reasons.

The argument about buoyancy has deteriorated to endless repetition of the same arguments which I won't continue, but if you want to know what real naval architects think about it you might read what they say in places like Boatdesignforum.net, like this one: Bow Shape - Boat Design Forums

You'll see it's pretty non-controversial among professionals that plumb bows and especially reverse bows are wetter and produce a greater tendency to pitchpoling, especially when combined with very buoyant, wide aft sections. If you want to compare a plumb bow boat with a raked bow boat which has a shorter waterline then -- well, that's your privilege, but you're missing the point. You have never addressed, and I guess you never thought about the issue of progressivity of buoyancy, but it's something that every professional thinks about.

You will also see that the pros are very much aware of the influence of FASHION on boat design, and they decry it just like I do. One of them calls reverse bows on cruising boats to be equivalent to spoilers on passenger cars, and decries the effect on boat handling. And these are the same guys who design such boats, under pressure from clients.

Another thing they say which is very relevant to this conversation is that bow form cannot be seen in isolation from the whole hull form -- it's much more complicated than we have recognized in this discussion -- hulls are three dimensional. The bow form is a function of the rest of the hull form and different bow forms can't just be stuck onto any old hull. For plumb bows you need straightish topsides, and for a reverse bow you need tumblehome, if you don't use a knuckle. Flared topsides require some rake in the bow, and all of these features work together with each other.

Another thing underlying this discussion is a simple question of taste. We all know that you are fanatically devoted to everything which is the latest and greatest, no matter how outlandish, but many of us simply have different taste.

Boat hulls are like architecture -- the forms, and even individual elements of form, express a certain internal logical and philosophy and "speak" to people in different ways. I don't like cantilevers because they express arrogance, it seems and feels to me, creating an impression that gravity doesn't exist and can be overcome in this crude way -- the architect simply drawing a straight line through the problem, rather than grappling with it, and letting the client buy a steel beam or reinforced concrete slab to solve the problem in a structurally inefficient way, a brutish application of material to just remove the design problem. And I love arches and other structures which live in harmony with gravity and express an intelligent and modest approach to solving the engineering problem, requiring work and thought and knowledge, instead of sheer tons of material, rather than just drawing an arrogant straight line through it. But that's just taste and I don't pretend to impose it on anyone else.

Likewise I love a boat hull with a bit of flare and a bit of rake to the stem, a bit of spring to the sheer -- expressing balance and scale, and intelligence and hard work, experience and knowledge of history, as it seems to me, whereas I hate hull forms which are all straight lines drawn with one arrogant stroke, as if there's nothing to it, as if there are no complex forces acting on boat hulls, as if there are no tradeoffs or hard decisions to make in boat design.

There's a "wedgie" Hanse 455 (or something) moored next to us in Copenhagen which makes me cringe every time I pass it. Tall absolutely straight topsides, flaccid sheerline, plumb bow, gigantic out of all proportion barn door looking transom, decks you couldn't walk on at sea -- to my eye, it's uglier than a rhinoceros' anus. To me, it expresses nothing but stupidity and arrogance, ignorance, ambition to make a fashion statement without any care or knowledge of how a boat works at sea. Drawn by a callow 19 year old, probably, who still has Lamborghinis taped to his bedroom wall.


That's outrageously subjective, I know, and totally a matter of taste, but I just thought I should put my cards on the table
__________________
"Parce que je suis heureux en mer, et peut-être pour sauver mon ame. . . "
Dockhead is offline   Reply With Quote
Old 17-05-2016, 14:58   #206
Registered User

Join Date: Feb 2011
Posts: 2,105
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by TeddyDiver View Post
Nope, it's about being price competive, key being more cabin space for the beaver (Sorry couldn't help myself)
True, beavers need space. And boats nowadays are becoming vacation condos and of course mid afternoon places to hook up with your favorite pet, beaver or whatever.

Whether it sails or not is not the point. Queen size bed, full bath(without tub), and climate control have become the sine qua non.
__________________
reed1v is offline   Reply With Quote
Old 17-05-2016, 15:01   #207
Registered User
 
Polux's Avatar

Join Date: Nov 2011
Location: Portugal/Med
Boat: Comet 41s
Posts: 5,765
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by TeddyDiver View Post
Nope, it's about being price competive, key being more cabin space for the beaver (Sorry couldn't help myself)
Off course, that applies to the racing boats too, that need a lot of space for the beavers

The fastest monohull is the Comanche and id designed with a big beam and all the beam brought back because beavers need more and more interior space
Polux is offline   Reply With Quote
Old 17-05-2016, 15:08   #208
CF Adviser
 
Pelagic's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Boat: Van Helleman Schooner 65ft StarGazer
Posts: 6,895
Re: Pilothouse Variations -- Boreal

Great post Dockhead:thumbup:
But tell us how you really feel
__________________
Pelagic is offline   Reply With Quote
Old 17-05-2016, 23:08   #209
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch
Posts: 1,828
Images: 2
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by Polux View Post
Off course, that applies to the racing boats too, that need a lot of space for the beavers
Not for beavers, it's just too much sailing gear and sweat below them to thrive. The thang with racing boats is the testosterone high on the weather railing that makes the thongs to tick, the higher the railing better they tick, thus the wide beam
__________________
TeddyDiver is offline   Reply With Quote
Old 18-05-2016, 03:37   #210
Registered User

Join Date: Mar 2011
Location: Caribbean
Boat: Oyster 66
Posts: 973
Re: Pilothouse Variations -- Boreal

Quote:
Originally Posted by Polux View Post
Off course, that applies to the racing boats too, that need a lot of space for the beavers

The fastest monohull is the Comanche and id designed with a big beam and all the beam brought back because beavers need more and more interior space
The earlier example you gave was such an extreme design it was almost a windsurfer.

This one is nearly a catamaran. So much of the stability comes from the form it might as well turn into one and stop pretending. Just drop the keel, fit boards and remove the unnecessary middle of the hull. It would be lighter and quicker too.

Then there are the foiling boats, which aren't really boats in a sense as their main function is to avoid floating if possible.

As soon as you give up being a liveable displacement monohull then design results in metamorphosis. I don't think the plan is to go that far.
__________________

__________________
poiu is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Boreal Sailboats Highwayman Monohull Sailboats 3 25-04-2016 12:43
Jedi's White Bread with Variations s/v Jedi Provisioning: Food & Drink 1 15-02-2011 20:25
gulf 32 pilothouse bearhill Monohull Sailboats 26 06-12-2008 08:58



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 07:16.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.