Saving Weight

[poiu]

How much difference does it make on a mono? I know it makes a massive difference on a light cat to go from under to overloaded, but on my 42 ton mono, probably not much?

I've thought about this and by spending a good chunk of money I could shave up to 3 tons off the boat. Maybe 1 ton for free or cheaply, going up in cost to unviable loony levels.

If I can do 6kt reaching in an 8kt wind now, what will happen if I am 2 or 4 tons lighter as an example?

[boatman61]

Rhetorical Question....
Someone commented that the extra weight 'sinking' one's hull increasing the waterline length thus increasing speed..
Would one not also have to increase the sail area to compensate for the drag created by the extra wetted surface..
Although my boat is capable of reasonable speeds, she's no light wind sailor being steel with 2 x 300L of water and 200L of diesel.. and rarely touches hull speed.. in spite.. or because of the hull add-on swim platform that stretches the 37ft design to just under 40ft.
So sometime in the future (if no eager panting wannabe appears) I reckon on fitting an inner stay and backs to put more drive in her.... cutter rig with 100% yankee..
Dunno how well it'll work but... Why not..??

[Canibul]

This is hilarious. One thread on CF talking about cutting toothbrushes in half to reduce weight, and another thread on CF at the same time talking about how many hundred pounds of barbells and weight benches people are adding to their boats to be bodybuilders.

[zeehag]

it takes 1000 pounds to make a difference, why mess with your range designed into your boat.
are you racing or cruising????
my boat prefers to sail heavy. she moves better thru water with a bit of heft. she has been stripped down by previous ownerś so far she is uncomfortable without added ballast. that will change soon.

if you are so worried about the weight on boat, diet or stay home. boat will be a lot lighter without ye.,

[med]

I could easily lose 2.5 tonnes by emptying the water and fuel tanks. And then another 13 tonnes by taking out the lead insert in the keel.......

That lead insert probably weighs as much as some boats the same length as mine!

[zeehag]

Originally Posted by med

I could easily lose 2.5 tonnes by emptying the water and fuel tanks. And then another 13 tonnes by taking out the lead insert in the keel.......

That lead insert probably weighs as much as some boats the same length as mine!

FINALLY

someone with halfa brane.

[barnakiel]

How much is my weight worth?

Well, our boat is mid-displacement (neither a pig nor a butterfly) I look thru everything and I get rid of everything we do not need every time we go for a big trip. Where we buy new stuff, we do consider its weight.

I have seen our racing neighbours removing the toilet bowl before an important race ...

So to say only perhaps and out and out cruiser with a big boat and small crew does not care?

b.

[barnakiel]

Originally Posted by poiu

How much difference does it make on a mono? I know it makes a massive difference on a light cat to go from under to overloaded, but on my 42 ton mono, probably not much?

I've thought about this and by spending a good chunk of money I could shave up to 3 tons off the boat. Maybe 1 ton for free or cheaply, going up in cost to unviable loony levels.

If I can do 6kt reaching in an 8kt wind now, what will happen if I am 2 or 4 tons lighter as an example?

She will accelerate better but she will go faster only as much as she gets higher out of the water, which in this case is maybe 1 inch multiplied by your waterline and divided by original wetted area. Read: marginally and possibly not visibly.

You can gain considerably more extra speed by keeping her bottom very clean, getting a feathering prop (unless you already have on), then also by better sails and better sail trim.

Then again if you also shed that extra 4 tons ... ;-)

b.

[zeehag]

i have sailed skinny minnies, light n bouncy, heavy skinnies, light n rolly bouncy pounders, medium flyers, and fat roly poly n fat comfy. i have truly sailed many load trims n load reduced sloops.
i prefer fat pig comfy, myself.
cruisers, do yourselves a favor. your boat was designed by a very smart man. smarter than you. LEAVE YOUR BOAT ALONE. sail it cruise it but donot take out weight to make her faster. it will NOT help. not one whit.
racers, YOU destroy boats without remorse nor regret, then twist o flex it to death. mind what you remove. it also will not help.

BRING ON THE WEIGHT!!!
my boat wants 2-3 more tons.
down n dirty, centered.

[mikereed100]

Originally Posted by thinwater

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

Have you noticed a difference in speed? I've considered doing the same but I wonder how much of a performance benefit I would actually see.

I have done most of the things mentioned on this thread; water-maker, glassed-in backing plates, getting rid of unused stuff, books and DVDs are on the hard drive etc. To be honest I don't see much of a difference. When we fill our fuel and water tanks the boat gains 2200 lbs and I always expect the boat to slow down but we seem to carry on as normal. We are surely a bit more sluggish but I don't notice it. I continue to try the lighten the boat but I am no longer obsessive about it. I particularly don't scrimp on tools or anything that will keep the boat running. I hope to eventually get rid of the band saw, drill press and chop saw, but will always carry scrap wood, fiberglass and epoxy. Hopefully the carbon fiber toilet paper will help to compensate.

[poiu]

Originally Posted by barnakiel

She will accelerate better but she will go faster only as much as she gets higher out of the water, which in this case is maybe 1 inch multiplied by your waterline and divided by original wetted area. Read: marginally and possibly not visibly.

You can gain considerably more extra speed by keeping her bottom very clean, getting a feathering prop (unless you already have on), then also by better sails and better sail trim.

Then again if you also shed that extra 4 tons ... ;-)

b.

After having filled up all the tanks recently and observing the waterline, I reckon on about an inch per ton. If slow speed performance is roughly proportional to wetted area then maybe each inch is only a couple of percent of my wetted area as a wild guess, so 2 tons weight reduction = 4% wetted area decrease. So a speed of 6kt becomes 6.24kt after a diet. Is that how it works?

[estarzinger]

Originally Posted by poiu

How much difference does it make on a mono? I know it makes a massive difference on a light cat to go from under to overloaded, but on my 42 ton mono, probably not much?

I've thought about this and by spending a good chunk of money I could shave up to 3 tons off the boat. Maybe 1 ton for free or cheaply, going up in cost to unviable loony levels.

If I can do 6kt reaching in an 8kt wind now, what will happen if I am 2 or 4 tons lighter as an example?

I don't have a polar for your boat in my vpp program, but on a Hanse 495, if you reduce the displacement by 10% it says you gain .2 knots in those wind conditions.

[cruisersfarm]

Originally Posted by mikereed100

Hopefully the carbon fiber toilet paper will help to compensate.

Omg. Dead over here. Joke of the year candidate.

[Terra Nova]

Often times more important than weight is where you put that weight. Removing a few hundred pounds from the rig makes a huge difference. Moving the same amount of chain far from the bow can make a noticeable difference. Where saving the same weight in floor boards, not so much.

[poiu]

Originally Posted by estarzinger

I don't have a polar for your boat in my vpp program, but on a Hanse 495, if you reduce the displacement by 10% it says you gain .2 knots in those wind conditions.

Is there really so little to gain? If I reduce weight by 10%, that is 4 tons. and for only a 3.3% speed increase!

Totally not worth it. It is also really hard to do 10%. That will mean living off nearly empty fuel tanks, nearly empty water tanks. Dumping the dinghy, motor and davits for a roll-up with oars. Throwing out the dishwasher, washing machine, isolation transformer, genset, aircon loads of lines and parts. Spare sail, changing to a carbon mast and rigging. It's as much as I can possibly do without ripping out teak decks and furniture and drilling lightning holes in my topsides.