I've got this report from Tayana for the Vancouver 460 Pilot
but don't know how good it is.

http://tayana46.tripod.com/safety.htm

If anybody can understand the Righting Arms vs Heel curve and
the numbers on this web page please let me know.

The consensus here seems to be that Tayanas in general are safer
bluewater yachts but I don't know if the pilothouse makes this
Vancouver 460 less stable or more dangerous.

Thanks again for your help.

Why is everything you post "Urgent!"?

Doesn't seem urgent to me; more like you don't know what you're doing,
feel you have to do it now, and don't want to do the research
yourself.

wrote:
I've got this report from Tayana for the Vancouver 460 Pilot
but don't know how good it is.

http://tayana46.tripod.com/safety.htm

If anybody can understand the Righting Arms vs Heel curve and
the numbers on this web page please let me know.

The consensus here seems to be that Tayanas in general are safer
bluewater yachts but I don't know if the pilothouse makes this
Vancouver 460 less stable or more dangerous.

Thanks again for your help.

The pilothouse likely won't make the boat any less stable than the boat
without it. In fact, if the boat was to ever go blow 90 degrees the
pilothouse would add to the righting moment with its' great buoyancy.

The Righting Arm vs Heel Curve is quite telling and disturbing. Ideally
the area under the curve when the boat is upside down is significantly
smaller than the area under the curve when the boat is right side up.
In this instance the area under the curve is fairly large indicating
that the boat is quite stable upside down. In fact it is almost as
stable upside down as it is right side up. Not great.

According to this curve the Angle of Vanishing Stability (AVS) is about
110 degrees. That is unsatisfactory. Most offshore boats are designed
with an AVS in excess of 120 degrees.

After looking around the net I would have to say that this graph of RA
vs HC is wrong. Tayana claims an AVS of 0 degrees which would make
sense given the buoyancy of the pilothouse (Provided the windows don't
break).

Check out: http://www.tayanayachts.com.tw/V460.htm

I would rather the Tayana over the Beneteau.

wrote:
I've got this report from Tayana for the Vancouver 460 Pilot
but don't know how good it is.

http://tayana46.tripod.com/safety.htm

If anybody can understand the Righting Arms vs Heel curve and
the numbers on this web page please let me know.

The consensus here seems to be that Tayanas in general are safer
bluewater yachts but I don't know if the pilothouse makes this
Vancouver 460 less stable or more dangerous.

Thanks again for your help.

I can understand this stuff. The stability of this boat
sucks to put it politely.

I've met Robert Harris. He's a good guy who has designed
some nice boats (the Vancouver 27/42 come to mind). But
this doesn't seem like one of the better built ones.

- Angle of vanishing stability of 110 degrees is pretty low.
I wouldn't go offshore in that sort of boat. Even fat
cruising Beneteaus manage better than 115 usually.

- the displacement is really quite high but it is to be
believed because they actually calculated it based on
measured drafts

- the ballast/displacement ratio is overly low, meaning a
tender boat with not enough stability

- the calculated GM is low (not a good thing; should be 3-
3.5' min.)

- the VCG is high (not good) at 1.32' above DWL. I suspect
the pilothouse is contributing to the high VCG

- the righting arm curve is ugly. The area under the 0 part
of the curve should not be nearly the same size as the
portion above. Maybe they were not including the pilothouse
in the calculation but I think it is there (see the bump in
the curve at ~70 degrees).

Summary: probably the pilothouse has made it too top heavy
to be an ideal offshore boat. Due to the size it won't be
knocked down or rolled easily, but if it does, it will take
a lot of wave action to re-right her and she will likely to
be upside down for quite some minutes. I would look elsewhere.

Evan Gatehouse

Gary wrote:
wrote:
I've got this report from Tayana for the Vancouver 460 Pilot
but don't know how good it is.

http://tayana46.tripod.com/safety.htm

If anybody can understand the Righting Arms vs Heel curve and
the numbers on this web page please let me know.

The consensus here seems to be that Tayanas in general are safer
bluewater yachts but I don't know if the pilothouse makes this
Vancouver 460 less stable or more dangerous.

Thanks again for your help.

The pilothouse likely won't make the boat any less stable than the boat
without it. In fact, if the boat was to ever go blow 90 degrees the
pilothouse would add to the righting moment with its' great buoyancy.

The Righting Arm vs Heel Curve is quite telling and disturbing. Ideally
the area under the curve when the boat is upside down is significantly
smaller than the area under the curve when the boat is right side up.
In this instance the area under the curve is fairly large indicating
that the boat is quite stable upside down. In fact it is almost as
stable upside down as it is right side up. Not great.

According to this curve the Angle of Vanishing Stability (AVS) is about
110 degrees. That is unsatisfactory. Most offshore boats are designed
with an AVS in excess of 120 degrees.

After looking around the net I would have to say that this graph of RA
vs HC is wrong. Tayana claims an AVS of 0 degrees which would make
sense given the buoyancy of the pilothouse (Provided the windows don't
break).

Check out: http://www.tayanayachts.com.tw/V460.htm

I would rather the Tayana over the Beneteau.

As mentioned in the other thread, the numbers and curve on my
web site were given to me by Tayana.

With the pilothouse filled with air I would also expect this boat
to have no stable state upside down. But in this case shouldn't
the AVS be 180 degrees instead of 0 ?

wrote:
Why is everything you post "Urgent!"?

Doesn't seem urgent to me; more like you don't know
what you're doing, feel you have to do it now, and
don't want to do the research yourself.

It's no longer urgent because I've already decided to
withdraw my offer for the Beneteau 473.

The broker(s) you're working with must love you.


On Tue, 06 Dec 2005 08:20:46 GMT, wrote:

It's no longer urgent because I've already decided to
withdraw my offer for the Beneteau 473.

Evan Gatehouse wrote:
wrote:

I've got this report from Tayana for the Vancouver 460 Pilot
but don't know how good it is.

http://tayana46.tripod.com/safety.htm

If anybody can understand the Righting Arms vs Heel curve and
the numbers on this web page please let me know.

The consensus here seems to be that Tayanas in general are safer
bluewater yachts but I don't know if the pilothouse makes this
Vancouver 460 less stable or more dangerous.

Thanks again for your help.


I can understand this stuff. The stability of this boat sucks to put it
politely.

I've met Robert Harris. He's a good guy who has designed some nice
boats (the Vancouver 27/42 come to mind). But this doesn't seem like
one of the better built ones.

- Angle of vanishing stability of 110 degrees is pretty low. I wouldn't
go offshore in that sort of boat. Even fat cruising Beneteaus manage
better than 115 usually.

- the displacement is really quite high but it is to be believed because
they actually calculated it based on measured drafts

- the ballast/displacement ratio is overly low, meaning a tender boat
with not enough stability

- the calculated GM is low (not a good thing; should be 3- 3.5' min.)

- the VCG is high (not good) at 1.32' above DWL. I suspect the
pilothouse is contributing to the high VCG

- the righting arm curve is ugly. The area under the 0 part of the
curve should not be nearly the same size as the portion above. Maybe
they were not including the pilothouse in the calculation but I think it
is there (see the bump in the curve at ~70 degrees).

Summary: probably the pilothouse has made it too top heavy to be an
ideal offshore boat. Due to the size it won't be knocked down or rolled
easily, but if it does, it will take a lot of wave action to re-right
her and she will likely to be upside down for quite some minutes. I
would look elsewhere.

Evan Gatehouse

I think the stability curves are wrong. If you plug the numbers into
the formulas at US sailing you get a much higher AVS. 110 degrees just
doesn't make sense. Not only that but the 460's keel, although
seemingly a little light, is bulbous with the weight quite low.
Something is wrong with that graph.

Gaz

wrote:
Gary wrote:

wrote:

I've got this report from Tayana for the Vancouver 460 Pilot
but don't know how good it is.

http://tayana46.tripod.com/safety.htm

If anybody can understand the Righting Arms vs Heel curve and
the numbers on this web page please let me know.

The consensus here seems to be that Tayanas in general are safer
bluewater yachts but I don't know if the pilothouse makes this
Vancouver 460 less stable or more dangerous.

Thanks again for your help.


The pilothouse likely won't make the boat any less stable than the boat
without it. In fact, if the boat was to ever go blow 90 degrees the
pilothouse would add to the righting moment with its' great buoyancy.

The Righting Arm vs Heel Curve is quite telling and disturbing. Ideally
the area under the curve when the boat is upside down is significantly
smaller than the area under the curve when the boat is right side up.
In this instance the area under the curve is fairly large indicating
that the boat is quite stable upside down. In fact it is almost as
stable upside down as it is right side up. Not great.

According to this curve the Angle of Vanishing Stability (AVS) is about
110 degrees. That is unsatisfactory. Most offshore boats are designed
with an AVS in excess of 120 degrees.

After looking around the net I would have to say that this graph of RA
vs HC is wrong. Tayana claims an AVS of 0 degrees which would make
sense given the buoyancy of the pilothouse (Provided the windows don't
break).

Check out: http://www.tayanayachts.com.tw/V460.htm

I would rather the Tayana over the Beneteau.


As mentioned in the other thread, the numbers and curve on my
web site were given to me by Tayana.

With the pilothouse filled with air I would also expect this boat
to have no stable state upside down. But in this case shouldn't
the AVS be 180 degrees instead of 0 ?
It doesn't really matter how you say it, as long as we both understand
that the boat will not stay upside down.

Gary wrote:

I think the stability curves are wrong. If you plug the numbers into
the formulas at US sailing you get a much higher AVS. 110 degrees just
doesn't make sense. Not only that but the 460's keel, although
seemingly a little light, is bulbous with the weight quite low.
Something is wrong with that graph.

Gaz

I didn't find the formula at US Sailing's site but...How do
you find AVS without using a sophisticated stability program
that knows the shape of the hull?

The US Sailing formula may give an indication of ultimate
stability (the capsize screening formula) but that is a very
simple rule of thumb.

The inclining experiment data, which does determine the VCG
of the real boat, is plugged into a stability program
(GHS/Autohydro etc.) that gives the stability curve.

Robert has retired fairly recently but he should be able to
help you with your questions.

Evan Gatehouse