Message for Jeff

magnusmurphy · #1 (**permalink**) 12-24-2002

Dear Jeff

Sorry for this unorthodox post, but I don''t know what elso to do to get an answer regarding the shallow draft Scheel keel of the Tartan 372 Im interested in. The question was posted just a few spaces down.

I would really appreciate your (and anybody else''s)opinion. Buying a boat is a MAJOR undertaking (for most of us), and I don''t want to end up regretting my decision for years and years.

This Tartan appears in good condition and I plan to view it soon. I''m unable to obtain any information regarding stability ratios or numbers anywhere. I would want to take any boat I buy offshore (Pacific NW to Hawaii and Mexico), and these isues are critical. I am NOT interested in racing.

M Murphy

jparker11 · #2 (**permalink**) 12-24-2002

M. Murphy,

Not Jeff, but here is a site which may help with your search for ratios.

http://www.boats.com/content/default_detail.jsp?contentid=7822

The Tartan 37-2 you are considering looks like a great boat. The sheel keel would be just one aspect of this design, and not very relevant to the offshore work OR PNW work you anticipate. We don''t have a bottom in the PNW (except when lost)!!!

PS Don''t look at that C&C 41 Custom sitting next to it!! <g>

magnusmurphy · #3 (**permalink**) 12-24-2002

Thanks for the comments.

Are you looking at the C&C?

In fact I''m a frustrated landlocked sailor (Calgary) and haven''t even seen the Tartan. I usually fly in to sail and plan to take extensive times off in the future to sail starting this year. Life too short to work only - and we don''t get a second chance to enjoy it. I''ve been looking at the Tartan on the web and have been talking to the broker a lot, and over an extensive period of time. Its decision time...

If you have seen it personally, please tell me your impression, and what you''ve noticed.

Thanks again.

M. Murphy

magnusmurphy · #4 (**permalink**) 12-24-2002

Unfortunately the link links to a review I''ve seen before. It doesn''t give any stability (for instance limit of positive stability) data. This seems to be a real problem to obtain for any sailboat. I wonder why that is. It seems so obviously important...

M. Murphy

WHOOSH · #5 (**permalink**) 12-25-2002

M & the group:

Stability numbers are lacking (from builders, magazine review writers and others) in inverse proportion to their importance - and you''d think boats with better ''numbers'' would capitalize on this omission and trumpet theirs. Another example of marketing folks talking down to their audience, perhaps.

But what''s even tougher is to run accurate numbers for a given boat even if you have the input variables, the reason being actual displacement can be highly variable even for successive hulls from the same manufacturer. That''s why U.S. Sailing''s available ''Performance Package'' for a given model can be so useful. You can select e.g. ''Tartan 372'' and purchase a complete info package & polars for that design, as measured by the USS staff, with the details of how the boat was equipped & measured (to which you can compare your own 372). See http://www.sailingonline.com and their on-line store for more info.

Just one data point: recently received a series of notes from a Tartan 37 owner sailing in the Caribbean who''s rudder skeg fell off. Happened at anchor (rolly conditions after an offshore leg) so he was able to retrieve it and hopes to reattach it more permanently. Geesh...

Jack

Jeff_H · #6 (**permalink**) 12-25-2002

I have been offline for much of this week and so I don''t recall seeing a prior post on this topic but I am not extremely familiar with the Tartan 372. I have seen them around and regularly raced against one in a beer can series when I had my Laser 28, generally beating them boat for boat (with our furthest ahead wins being in light air and in very heavy/gusty conditions), but I am not sure that short course racing really tells much about performance of a boats as different as these.

Scheel keels can be quite a good option if they are carefully designed. In principle Scheel keels are a specialized form of a bulb keel. They allow the center of gravity of the keel to be lowered by placing a lot of weight in the bulb.

Normally with shoal keels you really lose performance due to a number of factors: Loss of leading edge length (in a foil the leading edge measured perpendicular to water flow is the primary source of lift), increased tip losses and vortex, and increased keel area operating in the turbulent zone near the hull. While a Scheel keel does nothing for the lost leading edge length or the keel area in proximaty to the hull, a properly shaped Scheel keel acts as an end plate and directs water aft, reducing both tip losses and tip Vortex generation.

Properly shaped a scheel keel is also shaped to minimize the drag of the bulb through the water. The key to all of this is how carefully the keel was modeled and how shallow the keel actually is. Is is really pretty close to imposible to get decent windward perforance out of a 37 footer that is much under 5 or so feet in draft without a centerboard. The question then becomes how willing you are to live with less performance. That is something that is very subjective.

I really can''t tell you much about the Tartan 372''s stability. Probabably the best source of stability for a boat in the mormal heel angels is a US Sailing IMS certificate. (The are very inaccurate for a boat after the rail gets in the water as they don''t account for impact of cabin volume or the cockpit cavity on ultimate stability). You can try to get a US Sailing IMS certificate for the Tartan 372 but I am doubtful that a Scheel keel version was ever rated under IMS.

Jeff

magnusmurphy · #7 (**permalink**) 12-25-2002

Thanks for the reply Jeff.

I''m not interested in racing, but would like to take the boat I buy offshore by sailing from Vancouver to Hawaii as well as to Mexico along the Westcoast at some time in the future. More immediate will be trips up the inner passage to Northern British Columbia and Alaska.

Here are the only stats I''m able to obtain:

Additional Specs, Equipment and Information:
Builder/Designer

Builder: Tartan Designer: Tim Jackett

Dimensions

LOA: 37.2'' LWL: 31.0'' Beam: 12.5''
Displacement: 15,200 lbs Draft: 4.9'' Ballast: 7000 lbs

Engines

Engine(s): Volvo Penta Engine(s) HP: 38 hp Engine Model: 2003 Turbo

For what I want to do, would you think the shallow draft should bother me or not? I guess for gunkholing one could even see it as a plus. However, the sail back up North from both Mexico as well as Hawaii takes a lot of beating, and that I guess is what concerns me.

Thanks again

M. Murphy

Jeff_H · #8 (**permalink**) 12-25-2002

This is a pretty wild stab and anyone who has actually lived with one of these boats may come back with a different conclusion that has a lot more validity than my supposition.

7000 lbs of ballast in a 15200 lb boat is a reasonable ballast ration taken in absense of any other info. 4.9 feet is a little shallow for a 37.2 foot boat or a 21 foot waterline length. (For comparison, my 38 footer with a 32.5 foot waterline is the shoal keel version at 6''4 and the Beneteau First 38s5 with a 31 foot waterline and similar numbers to your boat has a 5''5" draft for their shoal draft versions. I cite both of these because they were in production about the same time as the 372, but that said the Beneteau was intended as more of a coastal cruiser while my boat was specifically designed for offshore use.)

The other aspect that comes into play on a boat like the 372, which has an interior that is really optomized for coastal cruising, is that much of the storage ends up being high in the boat. As you load up with cruising stores the boat''s displacement will increase pretty dramatically, as much as 3000 to 4000 lbs, and much of that is high in the boat. Now you have an 18000 plus pound boat with 7000 lbs of shallow ballast and that is not too good.

One other concern that I would have with the shallower keel is motion comfort. A deeper keel goes a long way toward dampening a boat''s motion, and a deeper keel''s lower center of gravity goes a long way toward increasing the roll moment of inertia, combination of which means a slower roll rate through a narrower angle and reduction in the tendancy for excitation rolling. Its one thing for a boat that was designed to be shallow to begin with but these boats were designed for a deeper keel and the shoal draft is something of a popular adaptaion.

Jeff

jparker11 · #9 (**permalink**) 12-26-2002

M. Murphy
I, too, am a landlocked sailor. However, I have this imitation ocean (Great Salt Lake) parked a couple of miles west of the house that is good for racing.

I have not seen the Tartan you are considering, and the C&C I reference was shown by the owner prior to the broker''s involvement. I have been considering a larger boat and partnerships to participate in one of the mainland/Hawaiian races (Vic-Maui).

I have maintained a slip and pocket cruiser in Bellingham since 1987. For the cruising areas you are contemplating, the underbody of that Tartan 372 is not required. So why accept the negative features of a shoal draft if you are going offshore and don''t want to change boats? Having said that, the Tartan is nicely equipped for wandering around the San Juans, which could keep you busy for years!!

I envy you your ability to carve out time for this endeavor,

magnusmurphy · #10 (**permalink**) 12-26-2002

I appreciate all the comments.

Buying a boat is more complicated than almost anything else it seems. THe possibilities and options (not even considering the opinions) are almost endless but alas, the budget is most certainly not...

As for time, I''ve realized that time waits for no man/woman. I''m in the medical profession and see the ravages of time everyday.
If we don''t "just do it" it will soon be too late.
I hope to "put my money where my mouth is soon....

Magnus Murphy