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Old 22-08-2018, 18:56   #1
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Multihull Weight Saving Stratagies

Not to include more carbon fiber and foam. I'm thinking things that are easily changed.
  • Batteries. Minimizing bank size. Possibly lithium.
  • Charging. Rigid vs. semi-flexible panels.
  • Saving power saves batteries and charging.
  • Anchoring. Lighter hooks, lighter chain, and rope.
  • Tenders.
  • What not to take. Clean lockers regularly.
  • Sails. But multihull sails need to be strong because they do not heel in the gusts.
  • Dyneema where practical. Often cheap if measured by unit strength.
Clever ideas?
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Old 22-08-2018, 20:19   #2
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Re: Multihull Weight Saving Stratagies

For me,

It depends on how anal you want to go............ are you chasing a few kgs or 100's

The big stuff, other than what you mentioned

Remove safety railing and tether on the cetreline

Synthetic rigging

Portable water maker

Rewiring will be good for me, have a look, you may be able to do it better/lighter/smarter

Go outboard motors if you are starting from fresh

Walk around the boat and look at everything and see if you need it or want it. If you do can it be replaced with something lighter. Can it be mounted more efficiently or using lighter materials. Can the heavy things be moved more centrally. If you have to replace something, see if that's an opportunity to put something lighter/better on.
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Old 23-08-2018, 04:31   #3
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Re: Multihull Weight Saving Stratagies

All good ideas except ground tackle. Don't lighten that.

Outboards for sure, minimal water tankage and use a watermaker.
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Old 23-08-2018, 04:45   #4
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Re: Multihull Weight Saving Stratagies

Batteries, water, people, and fuel are the most the weighty items on board.

If you can do without a wife/husband and kids, you're off to a good start

In all seriousness though. A lot of people have massive battery banks. My own is 675ah, plus a starter battery. In total that is 200kg.

Cutting that down to 420 (2x50kg), getting a generator (1.6kw Honda or Yamaha at 20kg) and ditching the starter battery (that I mostly didn't even have hooked up) would save me 80kg. That's basically the equivalent of offloading a decent sized German fellow.

Here's a more off the wall idea. Linen towels over big fluffy cotton ones. They are much lighter, more absorbent, and dry more quickly.
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Old 23-08-2018, 05:59   #5
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Re: Multihull Weight Saving Stratagies

First question is: To what purpose?

If you are weekend racing, you can get a lot more extreme...pull the fridge, air/con, mattresses, you name it...just about anything that won't sink the boat.

If you are cruising, you have to consider what you are trading off.
- Ie: a small rollup tender with a 2hp outboard will be lighter and can be stowed in more places but most would consider it not nearly as functional as a larger RIB with a 15hp outboard.
- Do you have a canvas enclosure on the back? You can save weight and windage removing it but do you really want to sit out in the sun/rain all the time?

Assuming cruising where it's nice to add a little speed but you aren't going to get extreme:
- Carrying appropriate water...this may or may not include a water maker. If you are looking at a 2day passage carrying enough water for 4 weeks is overkill. Maybe take enough for 5-6 days so if weather doesn't cooperate you have a good margin for error but aren't taking an extra 500lb of water. (and don't forget to dump the holding tank often under passage if not directly routed overboard).
- Composting head is also an option. Particularly if you are mostly in no discharge zones. (if you are racing bucket and chuck it is even better)
- Minimize packaging for food and gear.
- Related to the water, take appropriate fuel reserves to the trip. If you are doing a 5hr coastal trip, carrying 200hr of fuel is a lot of weight.
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Old 23-08-2018, 07:40   #6
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Re: Multihull Weight Saving Stratagies

From my time cruising the Med, the heavier boats seem much more settled at anchor when the swell comes in. i.e they don't tend to roll and dance around as much.
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Old 23-08-2018, 10:02   #7
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Re: Multihull Weight Saving Stratagies

While it’s a potentially contentious topic, and not to everyone’s liking, desiccating heads (erroneously, IMO, called composting) save a lot of weight. Saves water and power too, depending on the setup replaced.

Having been privy to a holding tank failure on a friend’s boat, knowing that desiccating toilets will never inflict that particular wretched experience on me makes me feel much lighter-hearted.
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Old 23-08-2018, 10:37   #8
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Re: Multihull Weight Saving Stratagies

Quote:
Originally Posted by Markusik View Post
While it’s a potentially contentious topic, and not to everyone’s liking, desiccating heads (erroneously, IMO, called composting) save a lot of weight. Saves water and power too, depending on the setup replaced.

Having been privy to a holding tank failure on a friend’s boat, knowing that desiccating toilets will never inflict that particular wretched experience on me makes me feel much lighter-hearted.
I'm very interested in this weight reduction.
Do you have any insight into best practices with these or links to the best ones?
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Old 23-08-2018, 12:16   #9
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Re: Multihull Weight Saving Stratagies

Cut half the handle length off our toothbrushes reduces weight and still makes them functional unless you have abig mouth.
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Old 23-08-2018, 12:45   #10
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Re: Multihull Weight Saving Stratagies

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Originally Posted by mikedefieslife View Post
Here's a more off the wall idea. Linen towels over big fluffy cotton ones. They are much lighter, more absorbent, and dry more quickly.

We love our cotton towels, but have changed them all out for BLACK ones.
They dry very quickly in the sun, and don't really show up as much when hung out on the stern pulpit and arch.
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Old 23-08-2018, 13:56   #11
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Re: Multihull Weight Saving Stratagies

See if you can come up with at least two uses for every item you allow on board ...
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Old 23-08-2018, 14:14   #12
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Re: Multihull Weight Saving Stratagies

Quote:
Originally Posted by valhalla360 View Post
First question is: To what purpose?

I like an intentionally open-ended thread. Personally, I've owned everything from beach cats to a Stiletto to a cruising cat. Saving weight always helps, but clearly the rules are different in each case.


It also depends on the purpose. Some people like cats because they sail flat and there is a big salon. Others like the speed. I've been in both camps, but the speed always matters.
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Old 23-08-2018, 14:16   #13
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Re: Multihull Weight Saving Stratagies

I have a policy of completely emptying our cat every winter, everything goes and all lockers, nooks, crannies and compartments are emptied. Then when summer cruising time comes around again you get to see every piece that goes back aboard at which time you can decide if it was actually used last season or just taking up space. You would be quite surprised how much crap gets taken for a sail every year and not actually used.
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Old 23-08-2018, 14:29   #14
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Re: Multihull Weight Saving Stratagies

I've tried fast-dry towels of various material. They really don't dry me very well. I prefer cotton terry, but smaller and dark colors, SenorM pointed out. They dry fast enough.

I like 2-purpose item, unless they do two things poorly. Conversely single-purpose items that really work are generally worth it.

Ground tackle is an area where you need to be smart. Not too much, not too little, and all purpose. There is a lot of weight up for grabs, and it is often at the bow, right where multis hate it. But no single answer.

Leaving things home entirely is best. Keep what you need--boating should be fun--but clean out at least annually, and be ruthless. "Stuff" takes space and makes finding things complicated. [edit--Vorpal beat me to it]

---

How much would you pay for a boat that was the same but 1000 pounds lighter? Surely it would be greater than price/displacement, but how much? $20/pound? $100/pound? Pick a number, and weight every choice against that. Adding a battery? That's $150 + 50x20 = $1150 total cost. More expensive than you thought, but maybe worth it. You decide.

This holds for monos too, of course. The penalty will be small in the bilge, but not that different bow and stern; no one likes a rocker.
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Old 23-08-2018, 14:58   #15
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Re: Multihull Weight Saving Stratagies

First off, you need to start with a boat that actually sails, including in light-to-moderate wind. Leave ashore the extra containers of fuel.

Dual outboard engines instead of diesel

Solar panels for primary power. No big generator, but instead carry a Honda 2000 for back-up.

Watermaker - DC powered - so you can run with 3-4 days water consumption in tanks, instead of full. Also, DC with power supplied by solar, so no generator burning fuel to power an AC unit.

Lightweight dinghy and smaller outboard. This isn't about weight as much as it is getting weight off of the stern, and improving water flow/exit there (i.e., no stern dragging!)

We carry 150 ft of anchor chain spliced to another 60 ft of rode. I don't think this is an area to save weight.
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