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GRKnebel 03-13-2004 05:41 AM

Caliber 28 Stability
 
I''m almost ready to purchase a 1988 Caliber 28 -- which is all the things reported in the tow posted SailNet Reviews

My wife and I are just 60, beginning sailors w/ only limited experience on other boats [19'' Flying Scotts, 28 O''Day, 31'' Irwin]. We will sail on the Chesapeake Bay; our intended use is Weekend Cruising, Week-long Excursions [1/yr..?] and Evening Picnics. We expect to "out-grow" the 28'' when we''re resdy to do more long-range cruising.

We''re attracted to the Caliber 28 because of its sound construction, good ventilation, good accomidations and potential to sail well, esp tacking upwind. The boat we''re looking at is rigged for single-handed sailing [Durchman Flaking, all lines lest to cockpit] My only reservation is whether the boat is "too light, bouncy & tippy" for in-experienced sailors

* the 10''-10" wide beam should make it "Stiff",
* BUT the Capsize Ratio = 2.25 [anything over 2.0 = CAUTION, get more info...].
* BUT the 3600# Ballast is 50% of the 7200# lbs displacement <-- perhaps this "counteracts" the suggested instability of the high capsize ratio

What can you tell me about "how it sails..?

Jeff_H 03-13-2004 12:03 PM

Caliber 28 Stability
 
First of all, as a new sailor you would not be aware that the Capsize Ratio really does not include many of the key factors that determine whether a boat is likely to capsize or not. The Capsize Screen Ratio and the Motion Comfort Index are both surrogate formulas that produce results that can be so misleading that any reliance on these formulas is makes no sense and in the worst case is a bit dangerous.

I know that I have explained this to you before but here it is again, both of these formulas were developed at a time when boats were a lot more similar to each other than they are today. These formulas only have limited utility if used to compare boats that otherwise are extremely similar. Neither formula contains almost any of the real factors that control motion comfort or seaworthiness. Neither formula contains such factors as the vertical center of gravity or bouyancy, neither contains weight or buoyancy distribution, and neither contains any data on dampening, neither contains the vertical center of effort of the sail plan, all of which really constitute the major factors that control motion comfort or the likelihood of capsize.

I typically give this example to explain just how useless and dangerously misleading these formulas can be. If we had two boats that were virtually identical except that one had a 1000 pound weight at the top of the mast. (Yes, I know that no one would install a 1000 lb weight at the top of the mast.) The boat with the weight up its mast would appear to be less prone to capsize under the capsize screen formula, and would appear to be more comfortable under the Motion Comfort ratio. Nothing would be further than the truth. That is why I see these formulas as being worse than useless.

As to the Caliber 28, first of all, this is not a light boat by any stretch of the imagination. A moderate displacement 28 footer would be somewhere around 5500-6000 lbs. My last boat was a 4100 lb 28 foot performance cruiser. So if anything at 7200 lbs the Caliber is on the stoggy side of the weight range. While 10''-10" is on the beamy side for a 28 footer, this beam is carried at the deck, and not so much at the waterline. I doubt that this will be a ''stiff boat'' meaning with its deep canoe body and comparatively normal waterline beam, I would not expect this boat to have a lot of form stability. The Caliber 28 actually only has 3100 lbs of ballast, and with its shoal draft (meaning that the ballast is carried fairly high in the boat relative to the center of buoyancy), and a ballast ratio down around 42%, (Which become substantially less when loaded to go cruising), I would not expect this to be an overly stable boat. What saves the Caliber 28 from being "tippy" is that they are a bit under canvassed and so do not have the sail area to be quickly overpowered. On the other hand, the Chesapeake is a light air sailing venue and boats like the Caliber are a bit shy of sail area for our venue. As a result, there will be a lot of decent sailing days that may be lost to you.

It is not that the Caliber 28 is a bad boat for a first boat. They are reasonably well constructed. They sail half way decently. They are not as responsive as would be ideal, and lack tiller steering, both of which are very helpful if you really wanted to learn sail well, but the Caliber 28''s are a reasonable platform, albeit an expensive one for what they are, to get out there and putter about without getting into to serious trouble. They do not point upwind especially well, but they are not total slugs either. Any 28 footer will take some abuse from the Chesapeake Bay''s famous chop, but a 28 footer or less is really a good size boat for a first boat and a nice size for poking around the Bay. I had my last boat which was also a 28 footer for 14 years and really loved that size for poking into all kinds of neat places. As much as I love my current 38 footer, I sometimes miss the handiness of my former 28 footer.

Good luck,
Jeff



windship 03-14-2004 04:42 AM

Caliber 28 Stability
 
Jeff,
What IS the Capsize Screening Ratio based on?

Dennis

Jeff_H 03-14-2004 05:06 AM

Caliber 28 Stability
 
The capsize screening formula only has two factors, the gross weight of the boat and its beam. The formula does not include such extremly major items as sail area, or draft for example. It first becomes widely circulated shortly after the Fastnet Disaster as a short hand for comparing light vs heavy boats. That seemed logical at the time that the formula was developed because the only popular light weight boats of that era were early IOR boats which had notoriously high vertical centers of gravity, comparatively deep canoe bodies, lots of flare and heeled form stability, and very little dampening.

If you attempted to develop a formula during the period that the Capsize Screening Factor was developed and which was so simple that it took away all of the real factors that control the likelihood of a capsize, you would have only two types of craft to lok at in developing your numbers. At that point in time you only had traditional heavier weight sailing craft and early IOR boats, so you would of course conclude that weight was a major factor in predicting capsize.

BUT, in the twenty five years of studies that have followed the Fastenet Disaster, and the initial period of advocacy of the Capsize Screen Formula, weight in and of itself has been pretty much proven to have no real impact on predicting stability and the likelihood of capsize, which is why when the CE developed its STIX (Stability index), the formulas included so many other factors as well. Without sail area and vertical center of effort, weight distribution, buoyancy distribution at various heel angles, draft and keel area etc., any single formula that attempts to rate the likliness of a capsize is bound to be grossly misleading.

Respectfully,
Jeff

WHOOSH 03-14-2004 09:34 PM

Caliber 28 Stability
 
GR:

I think you''ve done a good job of identifying the uses to which you''ll put your boat and the C28 choice doesn''t strike me as especially contrary to them. It does strike me that you seem to be concentrating on this capsize issue in excess when there are other factors that are really important WRT your satisfaction with the boat - examples being draft and functionality of the cockpit (for sailing and relaxing), or berth dimensions and an easily used & stout anchoring system. I liked to hear you mentioning ventilation because that''s another such example. Where the concern for capsize comes from - for Bay sailing, where weather f''cast info is abundant and all your sailing is likely to be ''voluntary'' and on a ''one day at a time'' basis - I''m not sure.

I think it''s a real shame that the Caliber has a wheel, both because it''s going to be a boat with which you refine your sailing skills and because it''s a nuisance (and add''l maintenance task) that you could easily do without. If you''ll look around the marina, you''ll see I''m representing a tiny minority viewpoint...but were that my potential choice, I''d look at weather the ''emergency tiller'' set up could be retrofitted as a standard tiller system and consider removing the pedestal and wheel. It probably wouldn''t be a functional arrangement, but that effort at examination reflects how much of an improvement such a change potential holds. (I''d stick the pedestal back on when its time to sell).

How will the Caliber sell when it''s time to move up? They strike me as uncommon enough to be somewhat more difficult to move.

Jack


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