How to cut weight in a multihall

[bruceb]

I have a Crowther Buc33 that was built in fiberglass over foam hulls with glass over ply decks. I also had vintage ply bulkheads and interior. I have replaced most bulkheads and all of the interior with foam core glass and a little carbon fiber, replaced most stainless rigging with Dyneema, removed a few winches and I weighed everything that came out and went back in.

I reduced weight by about 360 lbs, well worth the effort on a boat the size of the 33, and I think the rigging weight reduction (60 lbs) really reduced the hobby horsing that Buc's are prone to. Added to using lighter equipment (and leaving extras at home) my sailing weight is about 500 lbs lighter, over a 10 % reduction. Of course, the boat is quite fast around the bouys, but I also think the lighter weight rig actually improves the overall survival conditions response of the boat. The boat accelerates instead of getting knocked down.

Light is better!
Bruce

[44'cruisingcat]

Originally Posted by tp12

Definitely the joke thread. Just need a few memes to be complete!

I was thinking that. Feeling a bit sorry for us owners of performance multis.

Add weight and they won't sail. Now we learn that they won't sail if we SUBTRACT weight.

Seems we just can't win...

[Tusitala]

a good way to lose useless weight in an older boat is going through and removing old coatings, interior, exterior and bottom paint. a gallon of bottom paint is like 12 lbs. multiply by the number of gallons per season, by the number of seasons worth of paint on there. some of the older boats you see have massive accumulation of old finishes that are cracking, peeling and largely ineffective. nasty job, but it's useless weight hanging there, and likely affecting performance. when refinishing the topsides I took the deck hatches off the boat to remove the old paint. the main inboard wing locker hatches are about 3' x 18". I don't know how many old paint jobs and nonskid I ground off but it removed 4-1/2 lbs from each of them. so a considerable amount considering it was just sitting there cracking and looking terrible. makes opening and closing the hatches much nicer too! we've followed a similar course with the interior too. in the end it might not seem like a huge savings, but the boat sits way higher on her marks and we get that much more payload .

[thinwater]

Not a joke thread. I've had cats that benefited from a diet. I had a Kevlar cat that was quite twitchy in strong winds to weather when she was stripped bare and light on crew, but she was a rocket ship off the wind. I think it is safe to say that all boats have a design range. For most of us, gaining weight (at home, the waistline, and onboard) is the more pressing concern. It's also a bit like saving money; how important it is depends on the situation.


Spring cleaning is vital, not just for weight, but for organization (a sailor needs to know what he has and where it is) and space. It seems every year I find spare parts for something I threw away or replaced! Or a gadget, that after a year, has proven frigin' useless.


A dry bilge. It's amazing how many boats haul water around down below, causing corrosion and mildew. My F-24 is a pain that way, but the PDQ is bone dry.

[mikedefieslife]

Originally Posted by thinwater

A dry bilge. It's amazing how many boats haul water around down below, causing corrosion and mildew. My F-24 is a pain that way, but the PDQ is bone dry.

I can't why there is any reason a cat would ever have water in the bilge unless something leaks. In which case weight probably takes a back seat.

[44'cruisingcat]

Originally Posted by thinwater

Not a joke thread. I've had cats that benefited from a diet. I had a Kevlar cat that was quite twitchy in strong winds to weather when she was stripped bare and light on crew, but she was a rocket ship off the wind. I think it is safe to say that all boats have a design range. For most of us, gaining weight (at home, the waistline, and onboard) is the more pressing concern. It's also a bit like saving money; how important it is depends on the situation.

.

So have you had a boat that sailed worse after you reduced the amount of junk on board?

Please no smartarse answers like "Yeah, after I took the sails off it didn't sail well at all."

I mean reducing dead weight. Have you ever had a boat's performance suffer from reducing it?

[thinwater]

Originally Posted by 44'cruisingcat

So have you had a boat that sailed worse after you reduced the amount of junk on board?

Please no smartarse answers like "Yeah, after I took the sails off it didn't sail well at all."

I mean reducing dead weight. Have you ever had a boat's performance suffer from reducing it?

In strong winds only, going to weather only, yes. I had a turboed Stiletto that was quite twitchy in a breeze and would not beat effectively if over reefed. The ratio of windage under the tramps and against the hulls becomes more important than the power generated by the reefed rig. This is made obvious by a lightly more exaggerated case; do you think you could sail a NACRA to weather in even 20 knots, single handed and sitting in the center? You could not. You might be able to creep to weather, but you couldn't tack.



This does NOT apply to cruising boats, even performance designs. They are generally heavy enough.


I think it is obvious that every design has a best range of weight. Above that, penalties accrue. Only the sailor can decide how much the penalty of being above optimum is worth, but I'd wager $15-30/pound would cover most multihull sailors.

[44'cruisingcat]

I guess that was an answer to a question, but not the one that was asked.

[Redreuben]

OP if you have the money to build a carbon fitout for a Searunner then you have the money to buy a faster/better boat than a Searunner from the get go. It’s just lipstick on a pig.
Making a high volume cruiser super light won’t make it a racer, the money is much better spent on a longer waterline boat.

[Training Wheels]

Go long and simplify!

[Capt.Timbo]

Originally Posted by Chotu

Of course the time it takes depends on the number, intricacy of the cabinetry and the size of your boat. Don't underestimate the hours. Go for the low hanging fruit first. Tankage, gear/equipment as mentioned by the others.

My point is, do the math. It doesn't save all that much weight assuming the cabinets weren't built with 3/4" ply or something outrageous like that.

How much does your current cabinet material weigh per square foot or square meter?

How much does your proposed cabinet material weight per square foot or meter?

How many square meters total are you replacing?

(Weight old material )x(area to be replaced)-(weight new material)x(area to be replaced) =????

Jesus! Are you going into a state of the art race? We added 987 lbs of glass and resins in re-controing our hulls and run a yahama 60 high thrust engine and still get 17 knots. Solid and ready to go at 2000 rpm, 8 knots, .08 gallons per hour and 7.96 miles per gallon. What is your ultimate objective? Www.winginit.shutterfly.com

[Lance]

Yes lighter is faster but the cabinets and internal structures can sometimes be essential to hull integrity go carefully .
Most tris Cross etc will provide very good performance without going to extremities whilst crusing.
If fast is the aim buy an ex race tri and add what you need.
Look for "Spirit" on her way around atm .

[Bean Counter]

Originally Posted by Capt.Timbo

Jesus! Are you going into a state of the art race? We added 987 lbs of glass and resins in re-controing our hulls and run a yahama 60 high thrust engine and still get 17 knots. Solid and ready to go at 2000 rpm, 8 knots, .08 gallons per hour and 7.96 miles per gallon. What is your ultimate objective? Www.winginit.shutterfly.com

7.96 mpg , say 8mpg = 1gallon per hour at 8 knots.

[Buzzman]

Madprops you are going at this bass-ackwards.

If, as you say, the intention is to 'cruise' to places where racing is happening, then offload all non-race-related gear on the dock prior to the race.

If the race is a longer distance, then carry minimalist 'lightweight backpacking' gear to suit.

If racing 'dock to dock' leave the anchor behind on the first dock.

If you want to beat the superlightweight modern tris by lightening an older boat, you are essentially wasting your time.

Not only have the hull materials changed, but hull shape, rig power and everything else too.

Just removing 50-100kgs from a 37' older tri won't cut it.

Basically any tri that doesn't have either a centreboard or dagger board won't really cut it against more modern 'racing focused' boats that are so fitted.

BUT, having said all that, if it's longer-distance 'cruising racing' - like Trans-Pac, or Brisbane-Gladstone or similar, then using some of the suggested lightening techniques would be of benefit.

On longer distance races, it's as much the luck of the draw, plus good tactics, that wins races - so if the windshifts fall your way, or you route the boat better to take advantage of forecast wind, you can still beat 'technically faster' more modern boats.

Based on what I've seen here in Oz, the accepted wisdom is to increase the height of the mast by 10-20%, increese the size of the sails and rigging to suit, reinforce chainplates etc to suit, utilise synthetic rigging to reduce the even-more weight up top (older boats tend to be more prone to pitching), and so on.

Rebuilding the cabinetry will not help you much much. Especially as trius tend not to have muhc in the first place, and it already tends to be pretty lightweight in the first instance, but sure, sacks will be lighter, netting will be lighter.

As others have suggested, removing a diesel and replacing it with a lighter two-stroke outboard will be more sensible.

It's like what super lightweight backpackers, mountaineers and cross-country skiers do - spend loads of money to replace items you can't do without with smaller, lighter ones.

So, for example, a two-burner gas stove and its propane cylinder aren't light. But an MSR single-burner backpacker/mountaineering stove is very light, by comparison. And the fuel it burns can be gasoline, so with the outboard, that reduces fuels needed to be carried, and reduces the number of containers. Aim not to motor much, so you only need fuel to get off the dock.

Gas cylinders = heavy steel; gasoline containers = lightweight polypropylene.

Instead of hiking boots, wear Crocs. Instead of jeans, wear thermal tights.

If only two aboard, share a cup, bowl, plate, knife, fork, spoon. It's a few more ounces.

I know that sounds almost ridiculous, but as someone pointed out higher up the thread, 1000oz saved adds up.

Replace the (probably) older Dacron sails with new, lighter weight Mylar or similar. Better cut, lighter weight. Which is heavier, roller furling or a second lightweight sail with plastic hanks?

Replace stainless blocks and deck gear with nylon and or Spectra soft-blocks. Every one replaced saves ounces. Ditch the stainless deckwear like pulpit, pushpit. Ditch the trampolines. It's all weight.

Fitting a hand-operated Katadyn watermaker saves both the electric motor to drive it and the battery capacity needed to run it, and the solar panels needed to supply them. Fit a smaller, lighter LIFEPO4 battery. Keep fit by 'making water'!
Make one gallon per person per day. But do it four times a day. So you only ever have one gallon on board. As you use it, replace it.

Ditch all the instruments except the compass and a mobile phone fitted with Navionics (or whichever). Race tactics software is available for cellphones. Leave the laptop at home.

Swap alloy spars for carbon-fibre replacements. Stronger and lighter.

But, seriously, you might as well buy a modern boat that has all the above already built in. It would probably even be cheaper (assuming you don't already own the 'older trimaran' you are attempting to make lighter.

Whatever you do, 'adding lightness' costs big money.

And if all the work you do only removes 100kg, sailing solo (ie: no crew) saves that without having to spend a cent.

See where I'm coming from?

[thinwater]

Originally Posted by 44'cruisingcat

I guess that was an answer to a question, but not the one that was asked.

It was not the answer you wanted. It did answer the question, but only half of it:

a. Yes, a boat can be too light to sail effectively to windward in a blow.
b. This does not apply off the wind. Of course, carrying too much sail off the wind in light boats can contribute to pitchpoling. You know this.


As for racing, I no longer care.