Heavy vs Light Displacement

[maxingout]

I sail on a heavy displacement catamaran, and I do it on purpose. I don't worship at the altar of speed. I am more interested in comfort and strength. Fiberglass is easy to repair when a problem happens. Repairing a carbon fiber yacht would be extremely difficult in remote cruising locations.

[rustypirate]

I would like to add something else to this discussion.

I firmly beleive in a saying I was told many years ago:

"There are 2 kinds of sailors,
those who HAVE run agound,
and those who WILL"

As a cruiser, you must take into account all possible situations that you can expect to find yourself in, and add on some that you cannot expect. Sometimes you will find yourself in a place where "proper" haul out facilities are not available, or maybe too many drinks were imbibed without checking the tide tables for the anchorage.

Personally I feel that the fin keel flat bottom designs are an accident waiting to happen if they ever have a grounding. There is simply not enough contact area to disperse the weight of the boat on the top of the keel without some other support for the hull. This situation gets worse when the boat starts to lay over and the forces are latteral rather than vertical.

Hulls with fuller bellies and higher displacements are designed to spread these loads across wider areas of the entire hull, and prevent damage.

One other thing. If your criteria for selecting a boat is based solely on sailing "performance", then you are setting yourself up for tradjedy. You will not allways be able to select the weather you sail in, nor the sea conditions you might find yourself in. Performance is OK, but if you are really in that much of a hurry to get to the destination, buy a plane ticket. Safety and comfort are so very much more important considerations than performance.

I also want to second the comments made about repairs. Carbon fiber is a wonderous material, but it is hell to repair. Fiberglass, Steel, Aluminum, heck WOOD is so much easier to repair especially in a remote location where proper facilities are not available.

[delmarrey]

The displacement of a vessel is proportionate to the age of the captain.

[Paul L]

Originally Posted by maxingout

I sail on a heavy displacement catamaran, and I do it on purpose. I don't worship at the altar of speed. I am more interested in comfort and strength. Fiberglass is easy to repair when a problem happens. Repairing a carbon fiber yacht would be extremely difficult in remote cruising locations.

Maybe heavy for a typical Cat, but still much lighter than a what most would consider a heavy cruiser of the same length. Heavy, light, medium -- all seem to be in the eye of the beholder.

Paul L

[Joli]

This is a circular argument.

Why weight? Power, load carrying capability and a soft ride.

Why reduce weight? It is possible to use a smaller rig, speed off the wind.

What does a cruiser want? Comfort and load carrying capability which brings us back to heavy designs. When you add weight (ie read cruising gear) to a light boat the SA/D falls off the cliff so now you have a boat with the waterline raised 8 inches, an anemic sail plan, and nothing but the dream of speed.

A side note: this analogy goes away as the boat gets bigger such as a Sundeer 64.

[andreavanduyn]

Joli is right ; above 50 foot or so it becomes more interesting to have a light weight performance cruiser.

What really surprises me is that till now nobody raises the point which is my personal motivation for light weight = getting the feeling back a bit as when I raced/sailed my little sailing dinghy when young........

Does that mean nobody feels this is an important fact why we do not buy a motorhome but a sailing vessel (which some people turn into a moving floating home )

Apart from my wife only one thing turns me on and that is going upwind in a real good breeze cutting trough the waves with the wind in my hair on the low side of the cockpit........

[Joli]

LOL, that's why they call it cruising. I don't want condo jumping for days on end.

Originally Posted by Xpets

What really surprises me is that till now nobody raises the point which is my personal motivation for light weight = getting the feeling back a bit as when I raced/sailed my little sailing dinghy when young........

[andreavanduyn]

point taken; not even a little bit when you can choose do to do?

some say sailing is like sex; when young you want to do it all day but when older when you choose to do so

[Joli]

Racing is fun for a day but when going distance would this be your ride of choice for 1,000 miles? My brother was aboard and he said it was a very nice sail but then again they had nice weather.

YouTube - Trans Erie Race 2009

transerie.com

Originally Posted by Xpets

point taken; not even a little bit when you can choose do to do?

some say sailing is like sex; when young you want to do it all day but when older when you choose to do so

[andreavanduyn]

true fun; have done this many times but this is on a 30 foot open dinghy

we talk 50' + YACHTS who behave very different with galleys for hot chocolateand fridges

[sneuman]

Originally Posted by Xpets

Joli is right ; above 50 foot or so it becomes more interesting to have a light weight performance cruiser.

What really surprises me is that till now nobody raises the point which is my personal motivation for light weight = getting the feeling back a bit as when I raced/sailed my little sailing dinghy when young........

Does that mean nobody feels this is an important fact why we do not buy a motorhome but a sailing vessel (which some people turn into a moving floating home )

Apart from my wife only one thing turns me on and that is going upwind in a real good breeze cutting trough the waves with the wind in my hair on the low side of the cockpit........

Xpets. I like the feeling of a Catalina 30, but I would not cruise extensively in one. You can't walk away from the helm. I enjoy steering for several hours at a stretch, actually, but I don't want to do it day after day. Been there, done that.

Many light, fin keelers (though not all) simply don't balance worth bumpkis and that is a real pain. But, it's precisely that unbalance that supplies the feedback you're talking about.

To me, one of the great satisfactions is finding that perfect tweak for the conditions that allows you to walk away from the helm and watch the boat sail herself.

[Paul L]

Originally Posted by Joli

When you add weight (ie read cruising gear) to a light boat the SA/D falls off the cliff so now you have a boat with the waterline raised 8 inches, an anemic sail plan, and nothing but the dream of speed.

The amount of weight that will cause a boat to drop one inch at the water line has nothing to do with the displacement of the boat. It only has to do with the area of the plane that intersects the water.
Weight for a 1 inch drop:
Hans Christeian 38 1,444
J/37 1,427
Tayana 37 1,274
Alberg 35 829


Paul L

[Cheechako]

Great point Paul L. The shape of the wetted part of the boat is the shape of the wetted part of the boat.. barnakiel said : "What does the choice of material has to do with the design's displacement???
Impossible to build a Westsnail in carbon?" Good point!
If a boat of a given shape is built lighter, it should carry more and sail better. I had a Hans Christian 38. What a beautiful boat and what a pig! Those of you who are worried about the jerky motion of a light boat at sea should try wallowing in a 3-5 foot sea and doing 3 knots over ground for several hours! (even motorsailing!)The whole time I had the HC my mind was going through how to make it lighter. It would have been simple if you ordered a new one. The Bronze beam that supported the traveler would be about 150 lbs on that boat! The steering pedestal was brass (?) I imagine it topped 200#. I replaced the forward teak hatch with an aluminum one in St Martin. That hatch must have weighed 40-50 lbs. I removed the nice teak "sea chests" that were on deck. In Trini I had the teak decks removed. Still, everything inside and what was left outside was way too heavy. Even the pulpits were thick 1.25 dia tubing. If you could get rid of all that crap, keep the same ballast and sail area, man the boat would probably really move, although it still might not go to weather too well... Strong is good, heavy is not..... If you think light is a problem, review some of Chuck Paine's designs etc wonderful, not too heavy, boats...

[idpnd]

Carbon fibre is meant to be rather stiff and splinter upon impact, making it very expensive to repair after collisions.

[sneuman]

Originally Posted by Cheechako

Great point Paul L. The shape of the wetted part of the boat is the shape of the wetted part of the boat.. barnakiel said : "What does the choice of material has to do with the design's displacement???
Impossible to build a Westsnail in carbon?" Good point!
If a boat of a given shape is built lighter, it should carry more and sail better. I had a Hans Christian 38. What a beautiful boat and what a pig! Those of you who are worried about the jerky motion of a light boat at sea should try wallowing in a 3-5 foot sea and doing 3 knots over ground for several hours! (even motorsailing!)The whole time I had the HC my mind was going through how to make it lighter. It would have been simple if you ordered a new one. The Bronze beam that supported the traveler would be about 150 lbs on that boat! The steering pedestal was brass (?) I imagine it topped 200#. I replaced the forward teak hatch with an aluminum one in St Martin. That hatch must have weighed 40-50 lbs. I removed the nice teak "sea chests" that were on deck. In Trini I had the teak decks removed. Still, everything inside and what was left outside was way too heavy. Even the pulpits were thick 1.25 dia tubing. If you could get rid of all that crap, keep the same ballast and sail area, man the boat would probably really move, although it still might not go to weather too well... Strong is good, heavy is not..... If you think light is a problem, review some of Chuck Paine's designs etc wonderful, not too heavy, boats...

That's interesting, because the parameters for the HC38 and the Tayana 37 are not that much different, but the T37 does surprisingly well in light air. I have no problem doing 3 knots in about 5 kts. of true wind -- and that's with a 130% genny and a 20+-year-old main that has, literally, gone around the world.

I admit you can't get that kind of performance with a cruiser's "good enough" mentality on sail trim. It definitely takes a racer's eye on the telltales.