How heavy is your boat and who says so?

Sans Bateau

Sans Bateau

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With some recent posts including the displacement of boats to illustrate a point, how heavy is heavy? For instance the Rival 34 is considered by some as a heavy boat. At 4954kg she is lighter than our Etap 35i, which is considered to be a lightweight AWB displacing 5200kg. Admittedly the Rival has BR of about 50% as apposed to our 33%. But with BR's now as low as 25% thats another issue.

Also I think some people are 'generous' in stating their boats weight. One boat quoted as being 8.5 tons is, according to the manufactures web site, 6.5tons. Is there considered an element of superiority in having a heavy boat?
 
Mine's is (unladen)

Hull Length 10M
Displacement 4500kg
Ballast 1400kg
Draught 1.6m
Ballast ratio 31%
kg/metre 450
 
Mine's

Hull Length 10m
Displacement 8000kg
Draught 1.65m
but no idea what the ballast ratio is....
800Kg/m

Numbers only based on what i've been told.... well... except the length.... I know its 10m, but my marina seems convinced its longer than that.....
 
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The only post I can see claiming 8.6 tons is mine. Care to enlighten me?

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Tome can you enlighten me? Are you inviting the lad to a piss up un your boat to relieve it of its vast ballast of booze and thus in a sense enlighten you and your fine craft thus enabling you to ghost like a spectre .. or just cruising tae gie him a bruising for accusing you of embelling the weight of yer wee boat?
 
That's interesting. I've always thought of the Sadler as a heavy boat but my figures are:

Hull length 8.7m
Displacement 3720kg
Ballast 1540kg
Draught 1.2m
Ballast Ratio 41%
kg/metre 428

It's the kg/m figure that surprises me by being so similar for the Beneteau and the Sadler.
Aren't these normally expressed as Displacement/LWL though?
 
But the rival 34 has far less hull volume.
Not that I consider the Etap particularly lightweight when compared with some other modern AWB.

My C 38 official figures are LOA 38'2'', beam 11'10, displacement 15900 lbs of which 6850 lbs ballast.
These are the factory brochure figures, although Catalina alledgedly have a habit of under quoting weight.

The shoal draught version carries extra ballast and weighs in at 16700lbs.
However, once loaded up with all the bits and pieces required to go sailing most owners reckon to weigh in at about the 20000 lb mark
 
Well, dunno how heavy is heavy...

The boat I race is supposedly 4945kgs displacement in the builder spec of which 1760kgs is supposedly ballast, although its been weighed, but cant remember what that was on the day. 10.9mtr LOA , 2.1mtr draft.

So whats that then? Heavy, light weight?

I say light weight, but I know its built like the preverbal brick out house, so does that make it a ‘heavy weight’?
 
My 'official' displacement is 4.7 tons. Last year, when lifting in, a crane driver reckoned the boat's weight was over 6 tons! Water and fuel tanks were full but it still quite a difference. This would change the BR from a fairly respectable 36% to a slightly alarming 28% (if my sums are correct).
 
Mine's...

LOA: 9.62m
Disp: 4500kg
Lead keel: 2000kg
Draught: 1.71m
Kg/m: 468

That's heavy, beleive me. I can only just lift it and even then, only for a few moments - and I sometimes go to the gym. But wait for this, last year, even the really big guys down at the boat yard couldnt pick it up - and there were a good few of them - in the end they had to use a crane.
/forums/images/graemlins/smirk.gif

Mark
 
This is what you call a heavyweight

Well here's RS statistics from the log:

Rival Spirit vital statistics
Sail number GBR7556T
Main sail area 268 sq ft (25 sqm)
Genoa sail area 420 sq ft (39 sqm)
Beam 3.4 m
Length 11.3m
Waterline length 8.9m
Displacement 9000 kg
I=43.4
J=14.33
P=43.63
E=13.75

Last time she was lifted she weighed in at 12 tons, god knows where the 3 tons have come (probably the contents of booze locker).
 
Firstly a lot of people mistakenly quote Registered Tonnage as the boat weight, ie the displacement, the two are not the same at all. Registered Tonnage is a volume measurement not a weight and could be nearly double the 'weight' of the boat.

Secondly there is the displacement quoted by designers and builders, this is a) a prediction and b) is a 'dry' weight ie with no extra equipment, anchors, chain, sails, or fuel and water.

Ballast ratio too can be misleading as the keel weight appears twice in the calculation, once included in the top line overall (probably predicted) weight and again under the neath as the divisor. In any case it takes no account of the additional righting moment (leverage) from a deeper narrower keel as compared to a shallow dumpy one, the type usually found on so called heavy displacement boats.

Our last boat a Westerly 33 was quoted (from memory) as having a displacement of 5.8 tonnes, a lot heavier than the similarly sized Moody 33s/34s. I remember once working out that if you took the keel weight away from both and compared the W33 with the later Seahawk, the W33 (hull only) was nearly 1000kgs heavier. What that proves I know not except that more materials were used to build it!

Our current boat has a (dry/predicted) displacement again from memory of 7800kgs which is only 34% more than our old W33 but yet is nearly double the weight of the Moody 33/34 models. Again what does it prove? You could argue that more hull weight equates to stronger, but don't include keel weight in that because it doesn't add strength and actually more keel needs more strength in the hull, a vicious circle! In our case the hull is laid up with Kevlar reinforcement too, more strength/stiffness for less hull weight. Compared to the W33 the wetted areas are very similar as we use precisely the same amount of antifoul, same make/type however the sail area is around 54% more and the dynamic LWL is 28% longer, all suggests good performance - I think!
 
Yes I've come across this as well. A friend of mine has a Sadler 26 which he thinks of as a traditional British pocket ship and a much higher displacement than any flighty foreign built yacht. But the facts are different. Sadler 26 displacement 2177kg, flighty foreign Etap 26 2270kg. As for Ballast ratio, the Etap has a bulb on the bottom maximising the righting moment for it's weight whereas the Sadler is just a fin with no bulb, but this isn't taken into account with ballast ratio calculations.

It's all down to perception isn't it.
 
When we had our boat in Holland the lift outs were charged by weight, not length, so the crane had a scale built-in. It was extremely chastening to see the difference between the lift-out weight (with all of the cruising "stuff" on board) and the drop-in weight after winter storage and before we loaded up again. The unladen weight agreed almost precisely with the stated displacement by the manufacturer.
 
To be able to compare one boat with another you have to compare the displacement or dry weight. As I believe that two identical boats one set up for cruising, could be, in real terms be much heavier than one dedicated to racing.

Its a good point that someone raised that with all the fuel and water plus cruising kit on board the BR will be reduced. Add to that the radar up the mast etc.
 
I'm concerned/confused. According to the Achilles website the displacement is 1180kg, ballast 643 kg, so 54%. This is presumably unladen weight.

At 7.24m this gives 163 kg/m, which is extraordinarily lightweight. The Achilles 24 is obviously not going to be as heavy as a yacht with an inboard engine, fridge, cooker etc but even so...

Or have I misunderstood/miscalculated?

Is it safe?! presumably a 54% ballast ratio is a good thing?
 
The sails alone on our boat are very heavy, both main and genoa are a 2 person job to lift. We also have a stern gantry with radar, wind and solar units, not to mention the bimini/cockpit enclosure. However we do stow the wine and gin just above the keel top so that must help. /forums/images/graemlins/blush.gif

People also often wrongly assume that a high ballast ratio makes for a stiff boat when often the opposite is the case. The ballast weight doesn't actually provide any righting moment until the boat is heeled and the ballast then has some leverage, more so in case of a deeper keel which has the longer righting arm. In the initial stages hull form is what makes for resistance to heel and of course the best example is a multihull, no ballast but wide platform. In fact some boats with high ballast ratios are very tender, narrow 'wineglass' sections means the boat will sail happily if not comfortably (unless you have one leg half the length of the other) on it's ear. High ballast ratios do not prevent rollover capsizes of monohulls either, it is the seastate not the wind that will be the prime cause of the capsize, except in open dinghy style boats.

A combination of hull form, ballast (ie weight of keel and depth of its centre of gravity) and to an extent length is what gives the boat the ability to carry the required amount of sail. Of course a heavy boat needs more sail area just like a heavy car needs a bigger engine, which in turn means heavier gear, more ballast and them more sail area again to counter the heavier gear and round and round we go again.

Uffa Fox a lifetime ago said weight was only of value in a steamroller.
 
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