[PUP] Fantale

[Tad Roberts]

Jim,

The likelihood that the Fantail 50 will have positive stability anywhere
near 120 degrees of heel is slim to impossible. Typical sailing yachts of
these (50' by 15.33') dimensions would have an angle of vanishing stability
of about 110 degrees.  These are boats with substantial (and deep) outside
ballast keels and no high deckhouse. In this size boat 3500 pounds of
ballast is a drop in the bucket, four times that might start to make a
difference in VCG height.  But still the boat is so shallow that the ballast
can't be very deep.  The shallow draft, wide beam, and high deckhouse will
add up to an angle of vanishing stability of approximately 80 degrees.

When anyone states stability data they must show some documentation,
otherwise it's just sales talk.  The stability data must show a curve of
righting arms at a given displacement and VCG height.  Usually stability
curves are given at several "load conditions". The first load condition
might be "light ship", this is the complete boat without stores, crew,
liquids, or owner's items aboard.  The second condition should be departure
or full load.  This is the complete boat with everything aboard including
all tanks (except black and grey water) full.  Normally this is the heaviest
(largest displacement) and lowest VCG, thus the highest stability. The final
load condition is "worst case" or arrival condition.  In this case the tanks
are at 10 percent, stores are depleted, but crew and owner's items are
aboard.  This means the boat is floating high in the water with a high VCG.
Worst case stability is the final criteria.  

The stability of your boat safeguards the lives of you and your crew, thus
it is worth paying attention to.  The correct data for your boat can only be
ascertained by the input of proven information.  The vertical height of G,
the center of gravity for the entire boat, is subject to much guessing.
This is done because actually measuring the height of G is an elaborate
undertaking.  It is done by conducting what's called an "Inclining
Experiment".  This involves heeling your boat with controlled weights moved
a measured distance and taking measurements of the angle.  This data along
with the hull lines and current floatation are the inputs required to arrive
at real stability that applies to your actual boat. It is not good enough to
state that an inclining has been done on another similar boat.  These boats
are now 20 years old and many changes (additions) have occurred.  There may
also be hidden differences in construction that can throw data off.

The Fantail 50 has always appeared to me to be an unhappy vessel, to my eye
they appear top heavy with too large and high a deckhouse.  Also someone
miscalculated the weights and they all appear noticeably down by the stern.
Be aware that fuel consumption will be quite a bit more than 25 gpd at 8
knots, perhaps double that.  To get the 1700 miles you will need to slow
down to 6 knots or less.

All the best,

Tad Roberts
www.tadroberts.ca
            

-----Original Message-----
From: passagemaking-under-power-bounces at lists.samurai.com
[mailto:passagemaking-under-power-bounces at lists.samurai.com] On Behalf Of
Highlan875 at aol.com
Sent: Wednesday, December 24, 2008 8:09 AM
To: passagemaking-under-power at lists.samurai.com
Subject: Re: [PUP] Fantale

We researched that there is 3500 pounds of ballast in  the keel which keeps 
the motion gentle and gives a righting moment past 120  angle of heel. I'm
not 
sure if this ballast was increased as the designer  suggested. 
 
We were also told that the Transworld 50' Fantale  Trawler burns approx. 25 
gallons a day with a range of about 1,700 miles. 
 

Jim Hughes