Muscle or Fat?

[Gary Wyngarden]

What do you think the ideal displacement for a boat is? As I think about cruising in my Hunter 37.5 to some places where the wind and waves can be punishing, I wonder about the strength of her hull, deck, coachroof etc., compared to other makes. A comparison of the displacement of boats of similar size gets interesting.The nominal displacement of my 37.5 is 16,500 pounds. The Beneteau 38 is in the same ballpark at 17,416.At the very high end you could go for a Globe 38 at 32,000 pounds, a Hans Christian 38 at 26,500 or a Nauticat 38 at 24,200. These boats are generally described in ads as "robust" or "go anywhere boats" or "designed for the North Sea". The ads don't talk much about speed though.The self-proclaimed queen of the cruisers, The Island Packet 38 weighs in at 21,500 pounds. The Catalina 38 is somewhere in the middle at 19,500Do the Hunters and Beneteau's weigh less to cut costs and is their strength compromised as a result? But then spendy boats like a Morris 38 only weighs 15,600 pounds and a Sabre 38 only weighs 16,900.So what's with all the extra weight? Sure some of it's in tankage etc. But does the added displacement of up to 50% give you a lot more muscle or is it just extra fat to haul around that needs more sail area or results in slower speeds?If you have any thoughts on the subject, feel free to "weigh in" Gary WyngardenS/V Wanderlust H37.5

 

[David]

Interesting

I had a similiar thought a few weeks back as a result of a boat my brother was looking at.Some specs:LOA 31.5 ftLWL 27 ftDraft 4.5 ftBallast 3800#Beam 11 ftDisp 10,500#Specs on our boat:LOA 34 ftLWL 29 ftDraft 6 ftBeam 11 ftBallast 4800#Disp 10,500#We are longer and have more 1000# additional ballast but the same disp... I received this response on the Trailorsailor website:"Think of displacement as a hole in the water made by the boat sitting in it. The water necessary to fill the hole weighs the same as the boat does. The boat [displaces/]10,500 lbs of water. If a boat has the same displacement yet the hole is a little longer (LWL) and the same width (beam), then the hole cannot be as deep (draft of hull w/o considering keel or appendages - or [canoe body draft/]). This indicates the longer boat has less displacement in relation to length. It weighs the same yet is longer. This is expressed in the ratio of Displacement to Length. As a general rule, the lower the D/L ratio, or simply D/L, the easier the boat is to move thru the water, ie., the bigger the "hole", the more water that must be shoved out of the way as it moves along. Moving water aside takes energy. Moving a smaller hole takes less energy, plus the longer LWL equates to a higher potential hull speed."HTHDavid

 

[David]

Hmmm re-reading your question

I am not sure I answered anything even remotely related... D.

 

[Seattle Scott]

A little pudge is fine

with the 17,800 disp on the hunter 37 cutter. I am not a deep thinker (OK we can least agree on this) so I looked for a compromise design. The 37C weighs 1,400 more than the 37.5, but 1200 of this is in the keel and the 37c has a foot less beam. I looked at the 37.5 the 37 and the 37C. I guessed the 37C would be less "exciting" and therefore more enjoyable to the mate and with a longer keel, maybe would track better than a fin keel, but still get in/out of the marina better than full keel. I have to give up 1/3 knot in hull speed to the 37.5, but hull speed is a rare event, unless under power. So you look at the PHRF rating at about 175 and say the 37C is kinda slow at the end of the day. But I can tell my mate that the capsize number is less than 2. So the answer is 17,800 disp is best, unless light air, calm sea, or you want to surf some waves, or you are motoring all day, or you need truck transport, or .....

 

[Stu Jackson]

Weight and Strength

GarySeems to me that the difference in weight is primarily in the hull and deck, i.e., strength. The rigging may add a little bit, but it's still a mast, a boom and sails. The "go anywhere" boats are marketed just that way because they're built stronger, and thicker. That's pretty much confirmed by the weight / length ratio, which isn't much affected by the rigging or stuff inside, because, like the rigging, all have engines, berths, interior finishes, stoves, sinks, heads, etc., which weigh pretty much the same regardless of the hull in which they are installed (for a given length of boat).StuPS that's why they also cost soooo much more

 

[Stu Jackson]

Weight or Strength

GarySeems to me that the difference in weight is primarily in the hull and deck, i.e., strength. The rigging may add a little bit, but it's still a mast, a boom and sails. The "go anywhere" boats are marketed just that way because they're built stronger, and thicker. That's pretty much confirmed by the weight / length ratio, which isn't much affected by the rigging or stuff inside, because, like the rigging, all have engines, berths, interior finishes, stoves, sinks, heads, etc., which weigh pretty much the same regardless of the hull in which they are installed (for a given length of boat).StuPS that's why they also cost soooo much more

 

[Rob Leimgardt]

Secure For Sea

Gary,I think these Beneteaus are far too lightly built and poorly constructed for offshore use, so comparing them to your Hunter is not fair assesment. I would not take a Beneteau offshore, without giving her some major structural changes and upgrades. Someone else mentioned an Island Packet as a better choice and I would have to agree with them.Pick your weather Gary, and try to avoid any un-compromising situations.RL

 

[Pat McCartin]

Stu, I disagree

MY Cheoy Lee 38 is considered a "go anywhere" boat but only displaces 18,700 dry. I think alot of the displacement in the newer boats is minimized by the extensive use of fiberglass "furniture" on the interior. My Cheoy is mostly wood inside increasing the weight. I'm not sure anymore that displacement is a good factor for determining strength.Imagine a 37.5 made of Kevlar or carbon fiber. It would be very light but amazingly strong.

 

[Steve G]

Muscular Rigging

I have trust in the basic hull design of my Hunter '33. It may not be the ultimate "North Sea" design, but it is basically sound. What would worry me is the strength of the rigging (and the grossly underpowered motor should I need it). I recently docked next to an Island Packet, and stared with envy at the size of the hardware (turnbuckles etc) I could put oversized turnbuckles on my boat, but it would be for show since the knees, chainplates etc are still what they are. These are some things I will definitely be considering in my next boat.

 

[Rick D]

Big Isn't Always Better

Easy for me to say at 5'6". Seriously, I don't think production boats of the last 15 years are light. I think most are moderate displacement by classic measure. I remember people saying how light Cal boats were and how they would break apart. They didn’t. Same for Islander, Pearson, etc. Today’s boats carry a lot more of their weight in amenities, tankage, batteries, and equipment. Compare a 1964 Cal 40 to a 2004 Beneteau 393 to a 1975 Valiant 40. Numbers in that sequence:LOA = 39’4”, 39’3”, 39’11”LWL=30’4”, 35’1”, 34’0”Beam=11’0”, 13’1”, 12’4”,DRAFT=5’7”, 5’1”, 6’0”DISP=15,500, 17,152, 22,500BALLAST=6,000, n/a, 7,700 SAIL AREA=700, 763, 772.The Cal 40 is a classic race/cruise boat that dominated for a decade and was cruised all over the world. It is hardly delicate and has done well the last 40 years. I think most people today would say it is a stout boat. Compare that with the Valiant and you have a heavier boat, more tender and slower. The Beneteau compares favorably to the Cal 40. I think the point is that a modern, light boat requires smaller rigging and sail area and lighter hardware, It isn’t any less robust. And, if you can slim the hull weight down through good design, you can get more equipment and cabinetry. Further, with a bit more beam, you get form stiffness and volume. So, what exactly do you give up? Not much, IMHO. A softer ride in a heavy displacement boat, probably offset by a greater tendency to hobby-horse. Displacement will carry through a short steep chop better, and it will power more comfortably. It can arguably carry a bit more payload without losing trim. However, it will probably be slow in light air, less responsive and more difficult to handle as regards sheet loads, etc. I don’t think it’s any safer given good design of a contemporary production boat. It most certainly is more expensive. How many sailboats do you know that have broken up at sea?Geesh, Gary, I thought this was a quiz.Rick D.

 

[Tom S]

Didn't a Bene 40.7 win the

Sidney Hobart race last year. Very much an open ocean race that would never be considered a walk in the park. I don't own a bene and for different reasons some don't thrill me, but at least I thought I'd throw in that comment. So I believe there are at least a few boats made by some some of the bigger manufacturers that can be sailed on open water. I would classify the ones that have more emphasis on roominess at the dock as not in that category, but not all boats the manufacturers make are like that.

 

[robert taylor]

meat and bones

the meat and bones of the deal is this. the construction layup and technique is the key. newer high tech, s-glass, epoxy, foam core, vacume bag, baked hulls weigh half as much as anything else and are probably twice as strong. this has to do with the product of enertia. the same reason a tube is stronger than a solid bar of the same cross section area. rod rigging tied to the an integral frame will result in the most rigid structure. an overlapping hull/deck joint that is bolted will not come apart. check out the construction of the new c&c121. it is a 40 footer that weighs about 14,000 lbs. it is all sail and keel. the amenities are great below. most of the rest i have read here is hearsay. (lay-up schedule, hull/deck joint, backing plates for hardware, etc, etc, etc......just looking at weight isn't the answer)

 

[robert taylor]

meat and bones

the meat and bones of the deal is this. the construction layup and technique is the key. newer high tech, s-glass, epoxy, foam core, vacume bag, baked hulls weigh half as much as anything else and are probably twice as strong. this has to do with the product of enertia. the same reason a tube is stronger than a solid bar of the same cross section area. rod rigging tied to the an integral frame will result in the most rigid structure. an overlapping hull/deck joint that is bolted will not come apart. check out the construction of the new c&c121. it is a 40 footer that weighs about 14,000 lbs. it is all sail and keel. the amenities are great below. most of the rest i have read here is hearsay. (lay-up schedule, hull/deck joint, backing plates for hardware, etc, etc, etc......just looking at weight isn't the answer)

 

[robert taylor]

meat and bones

the meat and bones of the deal is this. the construction layup and technique is the key. newer high tech, s-glass, epoxy, foam core, vacume bag, baked hulls weigh half as much as anything else and are probably twice as strong. this has to do with the product of enertia. the same reason a tube is stronger than a solid bar of the same cross section area. rod rigging tied to the an integral frame will result in the most rigid structure. an overlapping hull/deck joint that is bolted will not come apart. check out the construction of the new c&c121. it is a 40 footer that weighs about 14,000 lbs. it is all sail and keel. the amenities are great below. most of the rest i have read here is hearsay. (lay-up schedule, hull/deck joint, backing plates for hardware, etc, etc, etc......just looking at weight isn't the answer)

 

[Jerry Clark H356 SV Persistence]

Hunter 356 vs Island Packet 380

I own a H356 on Kentucky Lake and have sailed it in some pretty strong winds and occassionally waves in the 4 foot range. When beating or reaching in these magnitude waves with 20-30 knot winds, my coachroof will flex and I will hear minor rubbing and creaking sounds where the interior bulkheads are rubbing the hull. This only happens in the extreme conditions and is not the least bit bothersome to me as the flexing absorbs a great deal of energy and I have not seen any ill effects such as cracks that have resulted from sailing in these conditions. Usually when these conditions persist on Kentucky Lake, I am one of the few boats out.Last month I chartered an Island Packet 380 to crusise from Charlotte Harbor to Key West. The weather was great for sailing with 15 to 30 knot winds from the NNE and then E on return with seas in the 4-6 foot range with occassional 6-8 feet. The 380 is a much heavier and more solid feeling boat than my Hunter and the bulkheads are fiberglassed to the hull so there is no rubbing or creaking sounds. The mast is keel stepped rather than deck stepped as on my Hunter so there was no coachroof/deck flex either. The beam on the 380 is 13 feet versus 12 for my 356. I felt very comfortable in the Island Packet.The question I asked myself was, would I feel as safe, given the flexing of my 356, in the same conditions and I have concluded that I would. I wouldn't want to be in a strong gale or major storm for a long period of time, but I don't ever plan on making an Atlantic crossing, but do plan on coastal cruising in Fl some winter soon. I looked into a comparably equiped new IP 370 while there, and the cost is about $165,000 more than my 356 cost. Is it worth the extra money? For me, I am more than happy with my 356 and think it is an excellant value and safe enough for the sailing I intend to do. If the Island Packet were on KY Lake, I would spend many hours not moving because that boat doesn't come to life until the wind is at 15 knots - not so with my 356.I have sailing friends that think you need a steel hulled full keel with protected rudder no matter where you sail, because someday you may want to go to Bora Bora. For me, I'll stay with the Hunter - and in the unlikely event I want to sail to Bora Bora, I'd probably buy something heavier before I go!

 

[Jack Tyler]

Weight is all but irrelevant...

...as a number of other posts suggest. Weight by itself doesn't take into account the materials, manufacturing technologies, fundamental design/engineering decisions, adequacy of sailing & propulsion hardware nor, let's not forget, the craftsmanship employed to build a given boat. Ferro and steel boats are perhaps the heaviest categories of boats in use today, and both types can be either very strong or very fragile, depending on their design & build issues.One problem we have as boat buyers/boat users is that it's misleading to infer general conclusions from anecdotal reports. One example is Tom's point about a Beneteau winning a Sidney-Hobart: sounds meaningful, but what were the conditions, how uniquely was the boat set up, how seasoned the crew, and what structural issues surfaced, or will surface, in that boat? A Danish sailor was telling me his delivery stories this summer, one of which included a Beneteau crossing to the Caribbean from the Med. First the sailing hardware gave out (they pulled into the Cape Verde Is. and had some things flown in...), and then the galley substructure started getting a little bit higher each day they were at sea (he wondered if he was shrinking!). No big storms, just the normal, relentless torquing & racking of structures over some weeks. Very hard to generalize based on either that Trans-Atlantic or the Sydney Hobart, I'd say.My impression is that, picturing a conventional X-Y graph with cost on the vertical axis and weight on the horizontal, there's a U-shaped curve in place. Boats that weigh a lot and a little fall higher up the two ends of the curve (in the case of heavier ones, because more labor is also involved, not just more cost of the materials). The high-volume production boats plop around the bottom of the 'U', somewhere in the middle. The Z axis is, I guess, structural qualities but I surely can't equate it easily to X and Y.Jack

 

[Stu Jackson]

Pat, Good Point

Hmm, looks like another urban legend myth about boat weight has been summarily dismissed as foolhardy.Well, I gave it a try and learned a lot!You can stuff two pounds into a one pound bag after all Thanks,Stu

 

[p323ms]

Now it gets harder

Quality is often an intangible. Weight is concrete and easily measurable. How is a person to know about the engineering and construction of a boat??? I would venture that as a boat gets lighter the engineering and construction become more critical. Also I would venture that a boat that is built a little heavier is probably a little stronger, especially as it gets older. But as a lay person looking at a boat how can I know if the extra weight is fiberglass in the right places?? Or the reverse that the light weight is the result of cutting corners and not adding the extra layers of glass that are needed. Is the finished product more like an egg shell or a ping pong ball??? I have no doubt that a ping pong ball can cross oceans and bounce of rocks. But the egg shell probaly won't last very long.

 

[robert taylor]

meat and bones

the meat and bones of the deal is this. the construction layup and technique is the key. newer high tech, s-glass, epoxy, foam core, vacume bag, baked hulls weigh half as much as anything else and are probably twice as strong. this has to do with the product of enertia. the same reason a tube is stronger than a solid bar of the same cross section area. rod rigging tied to the an integral frame will result in the most rigid structure. an overlapping hull/deck joint that is bolted will not come apart. check out the construction of the new c&c121. it is a 40 footer that weighs about 14,000 lbs. it is all sail and keel. the amenities are great below. most of the rest i have read here is hearsay. (lay-up schedule, hull/deck joint, backing plates for hardware, etc, etc, etc......just looking at weight isn't the answer)

 

[Joe]

Stu Jackson?

We are family members of a stu jackson from Spokane. Is this the same stu? Joe