Multihull Weight Saving Stratagies

[Franziska]

Get rid of two 100l freshwater tanks, replace by desalinator.
Replace household fridge by built in custom one.

Replace books by Kindle (Sigh!)

Change toilet to dry separating one.

Swap paper charts for the ones one actually needs.

Do all repairs to a good level and get rid of some old paint, wood and spares.

Reduce wardrobe when getting to warmer climates.

[Mike Banks]

To reduce freshwater tankage one can make up solar condensers to get drinking water.

I use blue polypropylene water containers which drop in to carpeted racks as water tanks. One need fill only as many as you need for each leg of your voyage.

Instead of twin dieseld or twin outboards--run ONE diesel engine and generator, and drive outboard legs using electric or hydraulic motors. You usually only need them for berthing and manoeuvring in close confines. When sailing they are hoisted clear of the water. If one has to make a long passage under motor, or may need to some day, diesel hydraulic or electric are proven to be effective as long as hydraulic fluid is cooled and fan-cooled electric motors are ventilated.


I also use polypropylene diesel storage in the same carpeted racks, with a carpeted locking bar to prevent movement. Storage of outboard fuel is in carpeted deck lockers using smaller 10 litre containers. The lockers with lids closed and bolted also serve as seats. One should NEVER bring volatile fuels such as petrol below decks.

Fuel containers, and water too, can be removed, lowered over the side into a tender and rowed ashore for filling. Each holds ten or20 litres of fuel or water. No rust, cheap to replace, and one leak--if you ever get one--will only dump at most 20 litres of fuel or water into your bilges.

It is a personal thing of mine--but I HATE not having the means for filling tanks by dinghy or tender. In most coastal cruising to interesting places, there are no dockside facilities, and a stroll into town with a 20 litre container and a golf-club trolley or a little rickshaw trolley such as is often towed by a bicycle, or of one's own invention means fuel can be collected with any shopping, and the trolley collapses or dismantles for transport back to the vessel or for on-board stowage. Before I got crook knees--a yoke was fine for a short walk. Now I use a trolley.

While one can shed some weight aboard by using 20 mm nylon anchor rode fastened to 20 metres of short-link 13 mm chain and a 10-20 kg kellet, never be tempted to replace a galvanised steel anchor with an aluminium one. Not if you want to keep your vessel from going ashore or heading off out to sea by itself..

I can not understand why SOLAS allows these things to be sold.

[Dave_S]

In my case I can add buoyancy.

These are the outboard wells in each hull. Within each hull there is about 117lt of water at rest.

I am going to seal these openings with closed cell foam and just leave the minimum hole for the outboards, then a hatch to cover the hole when the outboards are up, with a venturi drain that should keep most of the water out while moving.

I should gain 220kg of buoyancy + less drag in the water.

[thinwater]

[QUOTE=sailjumanji;2703366... 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.[/QUOTE]


Actually, you did. I did the same with a similar boat. That is enough for you to anchor on all-chain most of the time, and the rest of the time enough to provide catenary. Many mono sailors would think anything less than 300 feet is skimpy. You saved 150 feet of useless chain.


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High grade chain vs. BBB? What about grade 70?

[sailjumanji]

Originally Posted by thinwater

Actually, you did. I did the same with a similar boat. That is enough for you to anchor on all-chain most of the time, and the rest of the time enough to provide catenary. Many mono sailors would think anything less than 300 feet is skimpy. You saved 150 feet of useless chain.

When I purchased the boat, the PO had removed the windlass and was using a rope rode with about 15 ft of chain. Told me at 60 yrs old, he could haul rope easily and no one had any business adding the weight of chain to the boat. It took me about a month to install a windlass, and put the chain on the boat.

And I have never used any of the rope rode. Buy two friends had boats drag and ride up onto their anchor rode, and they ended up having to cut it to separate. With an all-chain rode, that is tough. So I added the rope, and spliced, and figured I'd add a little length in case I do eventually have to anchor in deeper water.

[Training Wheels]

Funny, when we bought our boat, the first thing I did was remove the electric windlass and the electric winch to save weight. Oh, I’m 58. I figure the exercise is good for me. Just went sailing on a mono with all electric winches, and I just don’t get it.

[sailjumanji]

Originally Posted by Training Wheels

Funny, when we bought our boat, the first thing I did was remove the electric windlass and the electric winch to save weight. Oh, I’m 58. I figure the exercise is good for me. Just went sailing on a mono with all electric winches, and I just don’t get it.

Yep, I agree. I'm a year older than you. But I wanted chain and didn't want to pull-up by hand. Plus when you have to move in a blow that someone else is dragging down on you, an electric windlass with switch at the helm is sweet.

[Training Wheels]

If someone else is dragging down on me, I’m tossing my rode and coming back for it later. Moving in a blow, my beautiful wife of 30+ years is motoring into it while I’m pulling up the rode. Did I mention that our chain is 1/4” G70?

[Nicholson58]

We have small microfiber towels, very light and they dry fast. They also are compact.

Composting heads: Air Head. Nature’s Head.

Don’t forget as long as you are economizing away the convenience and comfort of life to remove all beer, wine and liquor and ice.

We weigh 40tons, 400 gallons diesel, 280 gallons water, four anchors totaling 380#, 320 feet 7/16 chain, 17000# lead keel (monohull). We made Cheasapeake to Virgin Gorda in 7.5 days, 1500 Miles with 500+ Miles over a two day period in 16 to 25 foot seas. I would not have wanted to be doing this in a stripped down ultra light cat. (Or Mono) Just be careful what you compromise away. You may wish you had it back.

We were in Antigua for the 600 last season. Many hot light cats, tri’s and crazy monos took off from English Harbor in 30 knots or so of wind. There were a lot of broken vessels that never completed. One capsized. Many fins, wings, rudders, boards broken or missing.

[Training Wheels]

So, is that a Nicholson 58 multihull? All I can say is “no, not the rum!”.

[arsenelupiga]

enable watermaker to run while sailing. I only have up to 100 L of water for 2 days in tanks, instead of filling 600 L tanks.

On passage where performance really matters can save ~ 0.5T.

[sailorcherry]

How about adding some to lose some, by adding transom extensions?

We all know some owners added them and some builders also, ex. Seawind 1000 - 1000XL.

It seems added capacity aft sure would be nice for affording an arch to hold lotsa solar in the best charging location and lose weight by removing batteries and full water tanks for a watermaker. Or do it to make up for the added payload aft for a bigger/faster dinghy and water toys.

Not to mention the handling improvements (pitching and a little more speed), ideal swimming, dinghy and boarding platform.

It's a mod I've had planned for a long while for whenever I became a cat owner. It just seems like a good add-on at a low cost via diy or by a yard vs the builder reaping the benefits with selling you a 2'-4' longer cat.

Any before and after data would be really appreciated from owners who have done so already.

[thinwater]

Originally Posted by sailorcherry

How about adding some to lose some, by adding transom extensions?

We all know some owners added them and some builders also, ex. Seawind 1000 - 1000XL....

Absolutely. I added 2' to the transom of my PDQ; really cleans up the wake. A large number of cats cold benefit from this simple surgery. Also a nice swim/loading platform and a smoother ride. All positives.

Expensive if you are not a dab hand with FRP. Not too bad if you are experienced.

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Semi-flexible vs. rigid solar panels. I had rigid panels on the hard top for ~ 8 years before I sold the boat. Now I have a semi-flexible panel, but I don't know enough about the durability. 2-years, so far it's good. Both were Chinese. Now that I think about weight and windage, I like the semi-flexible better I think, but ONLY if you can support them well and stay off them.

Having enough panels also reduces the need for heavy batteries. A pair of semi-flexible Chinese panels can more or less replace a battery for similar cost but 1/4 the weight and perhaps longer life.

Batteries? How thin can you cut it, allowing for some deeper discharge (occasionally 70% discharge, instead of always limiting to 50%, recharging quickly to avoid sulfation) Is lithium worth the cost? I'm guessing that both of these depend on how you use the boat. Full-time cruise vs. day sail and short cruise are VERY different in terms of lifetime cycles; thousands vs hundreds in a normal life span.

[mikedefieslife]

Provided that the ship is within its designed weight specs. What is benefit of saving weight? I mentioned earlier in the thread that as far as I have seen, heavier boats are more stable anchor, and smoother, less violent movement (more dampened) than lighter ships.

I know that on my cat, that there is no noticeable difference in speed when I have full water tanks (300kg) compared to nearly empty (50kg).

[sailorcherry]

You must have a heavy cat then, right? Something not very performance oriented I take it?

Originally Posted by mikedefieslife

Provided that the ship is within its designed weight specs. What is benefit of saving weight?

I know that on my cat, that there is no noticeable difference in speed when I have full water tanks (300kg) compared to nearly empty (50kg).