Saving Weight

[Snowpetrel]

Less batterys, less electron consuming gadgets, and less electron producing gadgets like gensets and enormous arrays of solar panels. This all adds up pretty quick into some significant weight savings, but may make life less comfortable aboard.

Another good weight saving is with a dinghy. A lightweight dink with a small 2 hp outboard and 10 litres of fuel plus some oars is a whole lot lighter than a 10 hp on a big rib and the 40 or so litres of fuel it might need for a longer cruise. Of course this also has its limitations, but it's cheaper and provides good exercise, and much easier to drag up a beach, so it does have some pluses.

Headliner material is a good place to save weight. The weight is up high, and contributes little. Most boats it's pretty lightweight, but some have heavy ply or tongue and groove. Easy to swap out for 3mm ply or some of the lightweight plastic boards.

Spares. It's real easy to carry spares for everything. Most of the time you can rationalize it down to essentials. Especially engine spares. At the end of the day the boats a sailboat, and in my experience you a most never have the spare you need, and in many places the spare is a reasonably short wait by post away.
Two often spare parts end up rusty and damaged after years aboard.

Tools, hard to give up all those nice tools, but a modest kit can do pretty well if it's chosen with care. Hand tools can be pretty versitile eg how often are you going to need an electric plane aboard? A nice small hand plane kept sharp can do a good job, likewise a sharp handsaw can replace a heavy circular saw.

Remove useless structure. I cut the whole aft sections of the cockpit coamings off snow petrel. They where 3.2 mm steel and weighed a heap, all right down aft. I also took the two aft tanks out, one water and one fuel. With them full she trimmed by the stern and felt like a half tide rock at sea. I used the space for storage of light gear. Big difference all up in performance and seakeeping with these two mods.

Then I shifted half the chain into a locker well aft. She was much faster and dryer to windward, and safer downwind in a blow.

All the weight I saved meant I could add a few more heavy anchors to my arsenal...
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[UNCIVILIZED]

What about the option of adding a couple of feet of WL, via extended stern scoops?
More drag when the wind's super light, unless you shift some weight forward when such is the case. But other than the cost of the scoops...
Assuming that your rudder configuration allows for such.

And if you had a mind to, it's likely that even your rudders could go on a diet. Albeit, at a $ price.

The call on headliners is a good one. Albeit, thin glass skins, laid up on a mold table, or purchased off the shelf, are a good bit lighter than 3mm ply. It's 0.35-0.5lb/sqft sans coatings.

Engine room enclosures can be fairly easily rebuilt, using far, far lighter materials than most OEM ones. While often giving you better sound insulation at the same time, when done right.

Stainless & Sunbrella add on's can weigh quite a bit, as can anything & everything attached to them. And with multihulls, you can go with 1/3 less solar panels, easy, if you move them around in order to avoid shading. As they defiitely have the deck space.
And there's the flip side, what, electrically, do you have onboard which you don't NEED.

My rule for Everything onboard, when I lived aboard, was that if I hadn't used it in 6mos, or 1yr, then I didn't need it. And it needed a new home.
Thus, less weight onboard, & more $ in my wallet.

Also, how much stainless is onboard, which could easily be replaced with aluminum. And if you ever need to redo you chainplates, there's the Ti option.

[Terra Nova]

The headliner could be lightweight fabric/vinyl. A watermaker might allow a reduction in water tankage. Carbon fiber spars...

[Snowpetrel]

Originally Posted by UNCIVILIZED

The call on headliners is a good one. Albeit, thin glass skins, laid up on a mold table, or purchased off the shelf, are a good bit lighter than 3mm ply. It's 0.35-0.5lb/sqft sans coatings.

Interesting Uncivilized, how do these thin panels go floppyness wise. I've got to line out the new boat and I'm keen for a lightweight simple option. Do you add any sort of core? Gelcoat and Polyester resin, did you have in mind something more exotic?

[Snowpetrel]

Good light air sails and a willingness to use them can save a lot of weight in fuel.

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[UNCIVILIZED]

Originally Posted by Snowpetrel

Interesting Uncivilized, how do these thin panels go floppyness wise. I've got to line out the new boat and I'm keen for a lightweight simple option. Do you add any sort of core? Gelcoat and Polyester resin, did you have in mind something more exotic?

From what I can put together, it's the glue, in the thinner types of plywood, which makes them heavy for their thickness. Which is what prompted my comments on alternatives. Especially as with plywood, you'll both likely be sealing it, & adding some kind of finish to it, on top of it's weight.

I haven't used the pre-made composite sheet material, however some guys love it. Especially for tack & tape projects.
Though, pre-made, or self made, you could go quite thin, & then attach some thin, narrow, cambered battens to the side which isn't viewable. Thus imparting stiffness to the panels, much like in a deck.

I should think that cores would work too. Anywhere from 3mm - 10mm. As to what type, such depends on one's wallet, mostly. Go for carbon skinned nomex honeycomb panels, if $ is no object
Ditto on what you use in terms of "glass" to laminate them from, with something like CF being the stiffest, but priceiest. Although you can find it for $20/lb, with a bit of digging.
But since this isn't a structural application, you could get away with off cuts & 2nds of glass (cloth, probably on resin too).

I'd just go online & pull up the costs of half a dozen types of "glass", & the same for cores, & then see what would be the cheapest way to make a stiff, light panel.
Although, my intuition tells me that a single skinned panel, done on a mold table, so that it has a perfect surface. And then stiffened with a few lightly cambered battens, would be the cheapest.

Then the trick would be in mounting them, so that the curve/camber which you see, would be a smooth one, from deck edge, to deck edge. Broken up, only by the battens used to hold the panels to the overhead.
Yet the panels "under structure", & the battens holding them in place, need to make them tough enough/well supported enough, to have a decent lifespan.

The "catch" to it all, being, that to get really light panels, they'd probably not be the most tolerant of heavy hands handling them. Or being dropped, etc. Given how thin the skins would be.
Although you could run an extra layer of tape in the laminate, around their perimeters. That, or even some 1.5mm - 3mm ply, or DIY custom machined, super thin lumber strips. It's pretty resilient.

But if you went with cores in/on them, 3mm, 6lb/cuft foam only weighs 1oz/sqft (and you don't need foam that's that dense in this application). So you could make some crazy light cored panels, or even just put skins on one side & maybe just neat resin on the other. That, or something like a layer of 2ox veil cloth.
And like with cloth, there are off cuts & odd sized panels of core material, which can be found for cheap.

I'd want to try out making a couple of different types of panels, first, before commiting to doing a whole boat in them, but... On a multihull especially, every little bit helps.

When building light weight boats, usually it helps to set a limit in terms of how much you'll spend per pound, on a technique or material which makes things lighter. As the costs go up geometically, the greater the weight savings.

Oh, & I'm thinking that a pigmented resin, of the type of your choosing, would be the way to go. As I don't imagine that the panels will see much UV.
Although you could spray them with a few layers of some type of UV resistant clear coat when you were done with fabrication, if that's a concern. Be it varnish, LPU, or?

PS: As far south as you are, you could go the opposite direction on cores. Finding some reasonably thick foam, 1/2" - 2"+ & laminate skins to it, on a mold table. Thus you'd get the dual perk of; insulation, & nice looking panels at the same time.
Just test out the foam in question, to ensure that it doesn't absorb much moisture over time. As some of the stuff is terrible.

Also, if you build a mold table out o 2 sheets of Formica/Melamine, set at 90 degree angles to each other, & with a half-rounded cove joining them, then you can build all sorts of light weight furniture, pretty easily.

[GordMay]

We cut off our toothbrush handles to half length.

[ggray]

I replaced my plywood floorboards with floorboards I made out of Decolite (endgrain balsa).

[thinwater]

a. I've already stretched the boat 2'. No dragging.

b. Floors are an easy place to save weight, but perhaps one of the less valuable (center and low).

What is weight worth? Would you pay $10000 more for a boat that weighed 1000 pounds less (assuming zero change in sturdiness or utility)? In other words, paying $100 to save 2 ounces is unreasoned folly for most of us. $10/pound is more like it... or less.

[Cheechako]

Originally Posted by Cheechako

Small water tank, with watermaker. better for the watermaker to run often anyway. Of course if it quits in the middle of the pacific......
Dual fuel tanks of reasonable size. Never fill one until you need to make that 2 week crossing. Then empty it first!

The reason I say this is because this is where all the potential easy weight savings are.
120 gal water ~ 1000#, cut that to 30 gal water and you just lost 700#!
Ditto for fuel, although maybe not cut that far!

But then again, to a certain extent, why does weight matter? Your waterline defines your speed, are cruisers worried about how fast they can accelerate up to hull speed?

[barnakiel]

Originally Posted by Cheechako

(...)

But then again, to a certain extent, why does weight matter? Your waterline defines your speed,

(...)

;-)

The waterline defines only your TOP speed. In light to moderate wind, the lighter one will sail better and faster.

I think another strong factor is the forces required to operate it. Lighter boat requires less muscle, smaller winches, less fuel and ;-) less antifouling paint.

b.

[sailjumanji]

I have a watermaker that allows me to cruise with less water in tank. But I wouldn't Advocate less or smaller tankage. If the WM goes out you want to be able to carry sufficient water for gulf crossings, passages, etc. Fiberglass tankage is not that heavy to justify making it smaller by relying on WM.

[Hoosiersailor]

Get rid of ALL your clothes. A side benefit is you might make new friends while cruising or less depending on how you look with no clothes....

[med]

Originally Posted by Cheechako

But then again, to a certain extent, why does weight matter? Your waistline defines your speed, are cruisers worried about how fast they can accelerate up to hull speed?

Corrected that for you.

[UNCIVILIZED]

Originally Posted by thinwater

a. I've already stretched the boat 2'. No dragging.

b. Floors are an easy place to save weight, but perhaps one of the less valuable (center and low).

What is weight worth? Would you pay $10000 more for a boat that weighed 1000 pounds less (assuming zero change in sturdiness or utility)? In other words, paying $100 to save 2 ounces is unreasoned folly for most of us. $10/pound is more like it... or less.

$10/lb is a figure which I've used a good bit, in the past when working on multi's & light weight mono's. As, yeah, you get to a point of diminishing returns.

Like the guy who was having a custom 60' racer built, & was ready to write the builders a check for $30K in order to remove 20lbs from the boat, until...
The builder's called his wife, & she knocked some common sense into him, via Strongly reminding him, that she & the family had been trying to get him to drop 20lbs or ages.

As to floor boards. Yep, making stupid light ones is easy. As in ones which weigh on par with 1/4" plywood +/-. Depending on what you use in their construction.
Even ones which are tough to tell from full on Teak & Holly floor boards. And that are tougher/longer lived to boot.
Also, cost wise, they're quite reasonable, too.