My Weight...

Looking at anchors and weight is obviously important (although windage feels more important but harder to measure). My quick question is if the weight a manufacturer claims includes stuff like fuel, water, persons, dingy, groundtackle, etc?
My KK54 says it's 68,000lbs but I don't see how that could include the fuel, etc?
In other words if I add that in I really need an anchor for an 80,000lb boat. Or is it already included?

Thoughts?

Arthurc said:

Looking at anchors and weight is obviously important (although windage feels more important but harder to measure). My quick question is if the weight a manufacturer claims includes stuff like fuel, water, persons, dingy, groundtackle, etc?
My KK54 says it's 68,000lbs but I don't see how that could include the fuel, etc?
In other words if I add that in I really need an anchor for an 80,000lb boat. Or is it already included?

Thoughts?

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Anchor manufacturers are talking total dimensions and weight. Always err on the larger side. In fact, I recommend always selecting one size larger than their chart says.

Aurthur, was your boat hauled and surveyed when you bought it? If so, was there a Travelift weight provided?

All I know is my own 34 LRC is listed at 18K. The Travelift scales read 10K fwd sling, 14K aft sling for a 24K total as typically loaded. I was quite surprised.

Good question, I'll look but I don't think the lift system they used captured weight.
1200g of fuel and 600 of water is like 15000lbs so if it's included or not isn't a small thing...

KK should come very close.

Arthurc,
I thought you had a KK42.

Nomad Willy said:

KK should come very close.

Arthurc,
I thought you had a KK42.

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Last year you might have seen a bunch of posts about a k42, it fell through at the very last minute, although now I'm super happy it did! Really excited about my k54, picking her up from Philbrooks next week

I always assumed that a builders weight number was dry weight. I could be wrong.

Builders weights are almost always dry and very optimistic on the low side. They usually weigh one of the first boats and then make changes as they go and the add ons usually don't get added onto the weight listing.

dhays said:

I always assumed that a builders weight number was dry weight. I could be wrong.

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If they don't say, they are generally dry. However, most builders say what the weight is. Some say laden and unladen. Some say nothing. Some say at half load. Regardless, most are not very reliable, especially for any older boat.

So to be safe 68k plus 15k fuel/water plus 5k misc? Figure 88k for anchor sizing?

I prefer to select the anchor by using the largest that the windlass will lift , and still fit in the bow .

Using a 190 lb instead of a 125 lb anchor wont slow the boat , or the anchor haul.

Arthurc you're in a very fortunate position in that you can easily contact the manufacturer to get some updated numbers and there is a KK forum on the Internet that will likely have the information or members with the same boat as yours. I would certainly reach out to other owners and see what they are using. That would at least be a good starting point.

Ted

Builders always seem to be low. At best they only include partial tankage. add all your stuff, increased tankage, some water absorbtion and you will be a much bigger number. Have it weighed in the slings next time.

I know one boat that the maker showed 26k# but in the slings it was 12k# more. Bigger engines and transmissions, top canvas, dingy lift, anchor and chain, all the cruising stuff made the difference.

I dont trust any makers numbers, get it weighed. twice, on different lifts.

Thanks everyone, I know I could have just talked to my KK broker but was also interested about how the industry does it, like many things it sounds like there is no standardization. As far as my anchor goes I do plan on putting the largest one that will fit on.

Arthur your boat's weight is always going to equal the water it displaces. If you look at your documentation certificate you'll see gross and net figures based on the manufacturers hull measurements. If you overload the boat you'll notice it by the way she sits and moves through the water. As far as adding the biggest anchor goes your weakest link is going to be your windlass. Manufacturers recommend total ground tackle weight be no more than 1/3 of max pull since continuos pull for D.C. Powered units is considerably less.

I wouldn't use the documentation weight. Mine says 36 tons gross. In the slings it's actually 23 tons. Marine gross tonnage is a calculation based on volume not weight.

This shouldn't be too difficult on a modern design. Find out the displacement at DWL. The designer will also be able to tell you the disp at each inch above or below DWL. You'll need to confirm if your waterline is drawn (painted) correctly.

Regarding the boat equaling the water it displaces... that may work if the king wants to know if his crown is pure gold, but it's a bit tough to do with a full size boat, unless you have a really big bathtub .

"Builders always seem to be low. At best they only include partial tankage."

Sometimes builders will use the weight loaded for a world cruise to make the vessel seem more substantial.

The Westsail 32 almost never could be loaded to its advertised displacement.

bayview said:

Have it weighed in the slings next time.

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Over the years I've had all my boats weighed in the sling at various yards. None of them matched the weight that the manufacturer showed.

"Over the years I've had all my boats weighed in the sling at various yards. None of them matched the weight that the manufacturer showed."

Over the years I've had all my boats weighed in the sling at various yards. None of them matched the weight that the other yards showed .

Travel lift scales are notoriously inaccurate. Based on hydraulic pressure on winch motors. How tension in cable relates to pressure depends on how much cable is on spool, affecting radius of the pull.

Also, anchor load has more to do with windage and less to do with weight. Load a boat full of stuff and anchor load probably does not change much compared to same boat light.

IMO boat weight is important when waves or shearing forces are involved

makobuilders said:

This shouldn't be too difficult on a modern design. Find out the displacement at DWL. The designer will also be able to tell you the disp at each inch above or below DWL. You'll need to confirm if your waterline is drawn (painted) correctly.

Regarding the boat equaling the water it displaces... that may work if the king wants to know if his crown is pure gold, but it's a bit tough to do with a full size boat, unless you have a really big bathtub .

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Had an interesting discussion on Archimedes Law with my kids after going through the Peterborough Lift Lock. Amazing piece of engineering, built in the 18th century and self powered. Basically two big bathtubs with the descending one containing more water. They were puzzling over how it could work when the tub going up was full of boats but the tub coming down was empty of boats. Took a lot of convincing to satisfy them that the weight of the filled tubs didn't change by adding boats

Also agree that it can be determined by using float marks. Many racing sailboats that have strictly prescribed weight limits are not weighed for compliance, but rather have float marks installed bow and stern, allowing everyone to essentially see their weight. They are typically installed by measuring the distance from the sheer.