Hey! I need your opinion on Etap 37s!

Discussion in 'Sailboats' started by nunzioluka, Aug 30, 2007.

  1. nunzioluka
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    nunzioluka Junior Member

    Dears, I would introduce myself in this new forum that i have discovered since few weeks with big surprise and interest…I hope you will be patient with my English, not so perfect…

    I’m not an engineer or a technician, I have started to understand something more about non dimensional data with your threads and post in this forum. I’m just a sailor who jump from a boat to another trying to enjoy as much as I can sailing an knowing new experienced sailors who can teach me something new about sea and boats.

    So, at this point of my life I have decided to rent my house, pack my stuff and use a inheritance to buy a boat that I will use to live and sail around there (initially in the easy latitutudes, but who really knows where I will end up?) with my wife and trying to do some charter/ blue water sailing course for gaining some money.

    I have already read all your discussion about Seaworthy (hey! 50 pages! It took me a week!) an about the perfect cruising boat… here it is my question:

    can you help me to analyse the non dimensional data of the Etap 37s (the boat I was considering to buy) and in general to express a general impression from a technical and practical point of view?

    My first priority is safety
    (just an example about how strange I am:
    Over 40 knot if I stay on the deck I secure to my lifejacket a little “Pony bottle”, this kind of emergency bottle divers use if they run out of air during an immersion…just in case I capsize and I remain upside down)


    The data I have recollected are:

    LOA 36'11" (11.26 m.)
    LWL 32'6" (9.9 m.)
    Draft 6'5" or 4'5" (1.95 or 1.35 m.)
    Beam 12' 8" (3.85 m.)
    Air Draft 56'7" (17.25 m.)
    Displacement 13,970 lbs. or 6,350 kg. (deep); 14,410 lbs. or 6,550 kg. (shoal)
    Ballast 4,400 lbs. or 2,000 kg. (deep); 4,840 lbs. or 2,200 kg. (shoal)
    Sail Area (100%) 525 sq. ft. (47.25 sq. m.)
    Auxiliary 28-hp. Volvo 2030
    Fuel 30 gals. (116 l.)
    Water 65 gals. (250 l.)
    SA/D (100%) 14.24
    D/L 188
    L/B 2.92
    Ballast ratio 31% (deep), 33% (shoal)
    LPS 123¡ (deep); 121¡(shoal)
    STIX 41.38 (deep); 43.08 (shoal)

    ManOverboard said an a post that stix is not the only factor to take in considerations, but also:

    Static Stability
    Dynamic Stability
    Hull Form
    Mass distribution (and center of gravity)
    Moment of Inertia
    Aerodynamic induced rolling
    Rolling induced by waves
    Orbital velocity induced roll
    Ruder and appendage induced rolling
    Wave induced broaching
    Aerodynamic induced broaching
    Weightlessness do to extreme sinusoidal wave forms
    Heaving motion and capsize probability
    Rolling induced by heaving motion
    Parametric excitation and initial heal angle
    Hull form contribution to broaching
    Period of encounter
    Resonant magnification
    Metacentric height
    Dynamic metacentric stability
    Heavy verses light displacement
    Center of gravity as it relates to displacement
    Mass distribution as it relates to displacement
    Mass distribution and its effects on moment of inertia
    Wave anatomy and displacement interaction
    Damping of undesirable motions
    Aerodynamic damping
    Damping do to appendages
    Form damping
    Velocity effect on damping
    Curve of declining angles
    Capsize probability of a single breaking wave
    Directional stability
    Ruder control
    Redundancy of control systems
    Safety systems and probability of use
    Boat strength
    Acceleration tolerance


    How can I achieve this data? Is this so simple like asking to Etap or….what? I repeat, I’m such an ignorant about that!

    I have tried this boat once but just with light wind and the feeling was good, still there are some doubt about:

    Sail Drive (what a huge hole down there!)
    Spade rudder ( no skeg!)
    A bulb keel (I’m considering the shoal draft version)
    A sloop (I would prefer a cutter rig)


    In case I won’t choose this boat, my “B plan” would be the Malö 37: it’s my second option just because it’s more expensive, I coul afford it but it sucks me to spend so much…..

    If a win the lottery I wouldn’t have any doubt: Shannon 39 (but I’m not sure that price is a fair one….not even for that boat).

    In any case, my boat should be 37/ 40 feet long, I’m “young and strong” but I want a boat I can manage alone in any conditions, and that also my wife can manage in case of emergency and…one that I can afford to maintain!

    Thank you to all of you in advance!

    Cheers

    Nunzioluka
     
  2. Guillermo
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    Guillermo Ingeniero Naval

    Hola nuncioluka! Bienvenido a estos foros!
    If you provide me with an estimative of the body draught (without the keel) and heeling arm (distance between sails center of effort and lateral underbody center) for the ETAP 37S version of your preference, I will produce a more complete set of parameters and ratios and discuss them with you. Also a lateral profile drawing which includes submerged hull and keel will be fine (At ETAP's site, there's only an 'over water' profile drawing).

    About STIX for this boat, I bring your attention to the fact you have to substract 5 points out of the 43 (shoal version) you state, to better realize the 'seaworthiness' of the design without the influence of the unsinkability. Doing this you come down to 38, wich is just fair for a 37 footer.

    I admire your patience of reading the full 50 pages of the Seaworthiness thread! Perhaps you are interested in reading the STIX one too....:)

    Cheers!
     
  3. Guillermo
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    Guillermo Ingeniero Naval

    In the mean time, here some estimated numbers for the Shannon 39, Scutter, fixed keel version:

    Length/Beam Ratio L/B = 2,88
    Lwl/Bwl Ratio Lwl/Bwl = 3,04
    Ballast/Disp Ratio W/Disp = 0,37 (For the stated displacement of 18700 lbs. What loading condition...?)
    Displacement/Length Ratio D/L = 236,41 (I like all around cruisers to be between 200-250. Again same question as before)
    Sail Area/Disp. Ratio SA/D = 17,01 (Looks nice. Again same question as before)
    Sail Area/Wetted surface SA/WS = 2,35 (Good performer in light airs. Very rough approximation)
    Power/ Disp. Ratio HP/D = 2,47 HP/ton (Pretty adequate, to my taste)
    Hull speed HSPD = 7,68 Kn
    Potential Maximum Speed PMS = 8,34 Kn
    Velocity Ratio VR = 1,09 (OK, being around 1.1)
    Best motoring speed (1.1) CSPD = 6,3 Kn
    Capsize Safety Factor CSF = 1,81 (Good, but I would prefer it a little bit lower)
    Motion Comfort Ratio MCR = 30,30 (Just to compare with other boats of the same size)
    Heft Ratio HF = 1,05 (Good being over 1, but would be better a little bith higher)
    Roll Period T = 3,48 Sec
    Roll Acceleration Acc = 0,08 G's (Nice, being under 0.1, but would be better around 0.06 for an oceanic boat)
    Stability Index SI = 0,95 (Better a little bit over 1)
    Angle of Vanishing Stability AVS = 120 º (Although estimated, seems low to me for an oceanic boat)

    Would be very nice to know the real thing. You should consider asking the manufacturer, as well as asking him to provide STIX or, even better, stability curves for known loading conditions.

    Cheers.
     
  4. nunzioluka
    Joined: Aug 2007
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    nunzioluka Junior Member

    etap 37

    Thank you Guillermo!
    i will ask Etap for the datas you told me, as long as I receive a reply i will write you again, I hope they won't be scared!

    Anyway, a part from the non dimensional datas, what do you think about Etap 37? I'm just curious to know our opinion...

    About the stix discussion, well, i guess at the moment it's too much for me :eek:

    thank you again,

    Nunzioluka
     
  5. Vega
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    Vega Senior Member

    ETAPS are strong and seaworthy boats, but many of those points on the Stix number come from the unsinkability of the boat.

    On Boats, like on motorbikes, safety depends mostly on the driver, not on the choice of the motorcycle :D.... I am joking but what I mean is that seaworthiness has to do a LOT with what you know and the way you handle your boat.

    The way you rig and prepare your boat is as important as the boat itself. Etap can rig you the boat for deep sea. Find the right guy to talk too (on the Etap shipyard) and let him tell you what the boat needs, for what you want to do with it.

    Don't choose a furling mainsail. Choose a main with lazyjacks and automatic reefing system (Selden) and then ask them to fit an extra reef (three, instead of two). The last one will need two lines instead of one, but will permit you to always handle your boat without the need of leaving the safety of the cockpit and this is one of the most important factors on seaworthiness (especially if you sail alone or with an inexperienced crew).

    Any modern boat with 36ft or more, if correctly equipped, will be suitable for what you want to do, except if you want to go to high latitudes or cross oceans on the wrong time of the year. Assuming that all modern boats are reasonably well designed I would say that the most important factor is your experience and knowledge and the way the boat is equipped.
     
  6. nunzioluka
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    nunzioluka Junior Member

    Thank you Vega for your reply, i agree with you when you say seaworthiness depends mostly on who handles the boat and how it was equipped, believe me, i will remember it. Anyway I would feel safer knowing my boat had a forgiving behaviour with human handling mistake, and was able to resist bad hits from sea, and for what i have understood until now (but still,i'm not so sure) stix number, avs, and the other non dimensional factors can help me to figure out what would be that behaviour...maybe i worry too much about it!
    cheers
    luca
     
  7. Vega
    Joined: Apr 2005
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    Vega Senior Member


    Perhaps. :p

    Listen to what says Greg Eliot about the Etap 37. He tested the boat for Bluewater Sailing Magazine and he is a very experienced sailor, a man that have tested many boats:

    ""Workmanlike" is a good term to use when describing the general tenor of the boat. If it were a car, it would be a Volvo: not particularly sexy, not noted for its speed, but solid, straightforward, well made and, above all, safe. We were impressed at nearly every turn with the Etap's sensible, solid construction.
    …..
    The sailing performance is in line with the non-dimensional numbers. The SA/D, calculated with a 100 percent foretriangle, is 14.24, placing her at the lower-powered end of oceangoing sailboats, but the D/L of 188 saves the Etap from feeling underpowered. The ballast ratio of 33.5 percent reveals a boat whose motion won't be quick or harsh. We were able to get Elizabeth past her calculated hull speed of 7.64 knots under either sail or power, hitting eight knots often but never seeing 8.5.

    The Etap 37s has a CE seaworthiness rating of "A," or offshore, their top category. With the shoal, tandem keel the STIX rating is 43.08 and the LPS is 121 degrees. Both numbers improve with the deep keel, as expected, but not by a significant amount. For the six-foot, five-inch fin keel the STIX number is 41.38 and the LPS 123 degrees.

    The bottom line? The Etap 37s is a safe, comfortable, easily handled boat, designed and built with care and distinguished for its well-thought-out engineering. The double-hull building method produces a boat that is stiff, quiet, dry and, yes, unsinkable.
    ...
    Good value, good cruiser, perhaps less stowage space than on some 37-footers, but one of the most comfortable medium-sized offshore boats we have ever sailed on."


    http://www.bwsailing.com/01articles/issue/1103/boattest.htm

    I would prefer a Porche, but if you want a forgiving one, perhaps a Volvo would not be a bad idea:D

    Salut
     
  8. Guillermo
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    Guillermo Ingeniero Naval

    The whole thing from Greg Jones here, luca: http://www.bwsailing.com/01articles/issue/1103/boattest.htm
    but I think you already knew that, as your posted numbers in your first post coincide precisely with those in the article.
    Funny the mistake made at the very bottom of the article: After talking extensively about the Etap 37, somebody introduced a couple of paragraphs about the Amel Super Maramu Millenium! :D
    Cheers.
     
  9. Guillermo
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    Guillermo Ingeniero Naval

  10. Pericles
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    Pericles Senior Member

    Hello Vega,

    You have hurt my Volvo's feelings.:D He says he is a quick car! 300 HP and 260 kph on the track. And he's an estate.

    Pericles
     
  11. nunzioluka
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    nunzioluka Junior Member

    Thank you Vega!
    yes i knew the article but i'm happy to know from you that the tester is an expert...you don't imagine how many times i feel like reading more an advertising than a real test! So happy to know I can trust that test...
    by the way, i agree with you about the Porsche, but my girlfriend would say it hasn´t enough space for the luggage...:p
    by the way, i asked Etap all the datas Guillermo said...still not answer...let see!

    Cheers!
     
  12. Pericles
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    Pericles Senior Member

  13. nunzioluka
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    nunzioluka Junior Member

    Thank you Pericles!

    I think it's an Elan 37 not an Etap, anyway it's an interesting link, good to know it!
    cheers,
    Luca
     

  14. Pericles
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    Pericles Senior Member

    nunzioluka

    Of course! Sorry about that. My mind's going. :D

    Pericles
     
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