+50% displacement compared to 'light weight'. Is that realistic?

[Jausum]

Hi!

I am headed to look at a new (old) boat in a couple of weeks.
One major concern I have is that the seller states that last time he lifted the boat it clocked 7,2 tons which is 50% above the 4.6 tons stated by the designer.

Nothing has been done to explain this weight increase, no hull reinforcements or keel weight addition (to the current owners knowledge).
At the time the boat was weighted, the owner was living on the boat and using it for long distance sailing, meaning equipment must account for some of the increase.
He also estimates that removing all his stuff wil probably get the boat down to 6.5 tons. But that is still almost 2tons above what is expected.

The boat has big bowspirit increasing the headsail area by 15% and I calculate a SA/D of approx 15 for the 6.5 tons disp.
Designer states 17.6 with original SA and D.
It is a long keeled boat so a lot of wetted area and a high Disp/Length ration (around 300) for the 6.5 tons.
The boat has 2.2 tons ballast, so almost 50% if the disp. But with the increase in weight it is closer to 30%.
I am planning to use it for water sailing">blue water sailing at some point, but in the first years I will just use it for costal cruising in weekends and smaller vacations.

My concerns/questions are:
What causes this hugh displacement incr?
Will it be too frustrating to sail in lighter winds (i know it is not a light wind boat, but i would like to move in 10knots of wind)?
Will the ballast/disp ration be a problem?

Any other thoughts would be very much appreciated!!

[neilpride]

Which boat is it? If the designer states that it is 4.6 and the seller claims that it is 7.2, then it would seem to me that the travelifts have a dial that measures the suspended weight, faulty dial?

2.6 tons of stuff is impossible on that boat.

[Jausum]

Originally Posted by neilpride

Which boat is it? If the designer states that it is 4.6 and the seller claims that it is 7.2, then it would seem to me that the travelifts have a dial that measures the suspended weight, faulty dial?

2.6 tons of stuff is impossible on that boat.

Laurin 32
https://sailboatdata.com/sailboat/laurin-32/

I have also considered a faulty weight. But I can see from pictures that the waterline is 10-15 cm higher that what is expected. Which isn't far from the 2 extra tons of displacement.

I can also see that others with laurin 32s notice that the weight of 4.6 tons isn't really representing the actual disp. So being that these boats have been build by different manufactures and some home build they might just have a lot more material that the designer originally wanted.
I guess a good thing for durability, but...

[CSYChip]

Manufacturers rarely if ever weigh the boats when they are made and a lot of things happen on the production floor that can change the weight significantly from the design spec. Older boats that are in the water full time also absorb a bit of water. This is usually not a problem however if the boat has a cored hull or deck and the coring has gotten wet, that is a huge and sometimes irreparable problem. If the boat has a molded in boot stripe or waterline and floats at that level it probably isn't an issue.

[Jausum]

Originally Posted by neilpride

Which boat is it? If the designer states that it is 4.6 and the seller claims that it is 7.2, then it would seem to me that the travelifts have a dial that measures the suspended weight, faulty dial?

2.6 tons of stuff is impossible on that boat.

It is a laurin 32. https://sailboatdata.com/sailboat/laurin-32/

I have considered a faulty weight, but from pictures I can see that the waterline is 10-15 cm higher that expected, which about fits with the 2t increase.

Also, I can understand from other L32 owners that the 4.6t is rarely the 'real' weight. But more often 5.5-6 when loaded. But this is still some way from 7t loaded.
These boats were built by different manufactures and some homebuild (not this one) so I assume that they vary in how much material was actually put into the hull. Not a bad this for durability, but...

EDIT: Sorry i am trying to figure out how all the different reply options work, so I replied the same this twice

[Jausum]

Originally Posted by CSYChip

Manufacturers rarely if ever weigh the boats when they are made and a lot of things happen on the production floor that can change the weight significantly from the design spec. Older boats that are in the water full time also absorb a bit of water. This is usually not a problem however if the boat has a cored hull or deck and the coring has gotten wet, that is a huge and sometimes irreparable problem. If the boat has a molded in boot stripe or waterline and floats at that level it probably isn't an issue.

It has dyvinycell core deck but solid GRP hull. It does have an older teak deck that needs to be removed at some point, so i did consider if water could have gotten into the deck core. But surely that can be the cause of such disp increase?

I does float, but lower that what i would expect. I would say 10-15 cm lower. A bit more in the bow than stern due to a massive amount of chain in the achor locker.

[leecea]

My thought is that since you have no idea where the extra weight is placed, you also have no idea of this boats stability as compared to the original design.

[Fore and Aft]

Jausum before you start running around like chicken little pay to get the boat professionally weighed. We never trusted the travel lift scales when weighing race boats. We used a company that weighed trucks and they would come around and do the job. Pretty easy to do.
There's a million reasons why a boat could be heavier.
Cheers

[Jausum]

Originally Posted by leecea

My thought is that since you have no idea where the extra weight is placed, you also have no idea of this boats stability as compared to the original design.

I know that the boat has been sailing for +50 years and blue water sailing for the last 5.

What I don't know is how it 'feels' and how much wind it takes to move the hull etc.

But you are right I have no real idea about where all that weight has gone. My guess is extra glasfiber in the hull and equipment.. but I don't know

[Jausum]

Originally Posted by Fore and Aft

Jausum before you start running around like chicken little pay to get the boat professionally weighed. We never trusted the travel lift scales when weighing race boats. We used a company that weighed trucks and they would come around and do the job. Pretty easy to do.
There's a million reasons why a boat could be heavier.
Cheers

Haha okay, I will try not to run around like a chicken?
But if we don't get hung up on the exact weight, I can see that the boat displaces more water hence it is heavier than others of the same type.
So if you know a million reasons way it could be heavier, I would love to hear a few of the most common
Thanks

[boatpoker]

I wouldn't even make the trip to see it unless it was on the hard or somewhere you could dive on it. Massive hydrolysis, dinner plate sized blisters and delamination could be part of the issue below the waterline.

[UYA]

Originally Posted by Jausum

What I don't know is how it 'feels' and how much wind it takes to move the hull etc.

Maybe the best way to find that out is to go sail with it. Let the seller take you out on a light wind day and get a feel for the boat. Specs are one thing but trying it out is another...

[Fore and Aft]

Jausum here's a few reasons why a boat could be heavier. I have surveyed one home built cold moulded boat where the owner ordered to many timber planks. So he just glued an extra couple of layers on the hull. Another client thought the boatyard where he had purchased his empty hull from had skimped on the fibreglass so he added a number of extra layers of fibreglass. Then I know a yard that had two identical fibreglass trawlers built side by side. One trawler had a boat building crew led by a racing sailor and that boat turned out 300kg lighter than its sister ship. Those guys were religious in weighing all their resin and cutting the fibreglass cloth to the correct size. They were 100% professional compared to the other boat building crew. Then another ex fishing trawler builder I know fitted out a catamaran with heavy clunky interior more fitting for a log home. Another client building a custom yacht wanted more draft so he tacked another 6 inches on top of the keel mold. Extended the keel bolts and poured the lead. He didn't consult the designer and just went by gut feeling. Then there's me removing internal steel concrete ballast in a yacht. The owner and I made some calculations on weight and put new lead in place. We then launched the boat and added some trimming ballast before we glassed it all in place. That's just a few highlights of why a boat may be too heavy compared to its sister ships
Cheers

[Benz]

7 tons is not really heavy for a 32-foot full-keel boat. My CG31 weighs almost ten tons, and loaded for cruising, the waterline rises by 4-6 inches.
Once you figure out how to handle a heavy boat, and what to expect, they're a real treat to sail.
Getting rid of the teak deck will reduce a bit of weight, and if you can trim off some anchor chain (I never carry more than 200'), you'll get along toward having her on her lines.
Adding sail area can help a heavy boat move: I built a gaff rig on my CG that carries more sail than the standard Marconi setup the builder affects, and carries it lower down. Without completely re-designing the rig you could add a boomkin (someone's already added a bowsprit, right?) and get a longer boom to carry a larger mainsail.

[Searles]

To my mind the major problem with weight whether the stability is correct ,the alteration of the weight if correct may leed to a large alteration in the vsls stability,most older style cruisers have a ballast to bisplacement ratio of about 30 pc ,but like most things this is subject to design ,test sailing may reveal all ,try for different weather days ,.⛵️⚓️