Cape Dory 27 vs 28, Thoughts?

[Dixon Hemphill]

Go with thye 28. It's a tad big bigger overall and that 6'1" headroom in the cabin is a real plus. Never sailed the 27 but my 28 is the best boat I ever owned!

[Troy Scott]

GB,

I agree with Clay. The 27 is a big small boat and the 28 is a smaller big boat. The 28 seems more substantial than the 27. This was my strong impression 25 years ago when I sailed both occasionally. At the time I owned a Ty Weekender, a CD25 and a CD22 (not all at once, but in succession over three or four years.

[John Vigor]

You are touching on what I was trying to find out, safety wise at least. Can you explain a little more on comment of the 27 sailingn a little better than the 28? Size wise I'm looking at the 27, 28, and 30. All the 30's that I have seen a priced out of my budget, so I'm looking between the 27 and 28 in the Cape dory line. How much interior room difference do find between the 27 and 28?

Thanks

GB, the numbers alone indicate that the CD27 has better performance under sail, while the CD28 has the edge in accommodation and ocean-going safety, largely due to its comparatively smaller cockpit.

The 27 came into production two years after the 28, so one can surmise that Carl Alberg learned how to improve on the 28 in that time.

You'd think that the 28, as the bigger boat with the longer waterline, would always be faster than the 27 under sail. But other factors come into play here. Bill Crealock once told me that it isn't hull speed that counts as much as the ability of a hull to reach a high cruising speed with comparative ease. Very few boats maintain full hull speed for any length of time. The boat that more easily achieves a reasonably high cruising speed will always cover ground more quickly.

What makes a hull easy to push to high cruising speed? Sail area, for one thing, because it equals horsepower. Beam for another, because initial stability ensures more efficient use of sail area and shape. Ballast ratio, of course, for the same reasons as beam. And, if we're considering windward performance, the aspect ratio of the keel.

It just so happens that in all of these areas the CD27 is more efficient than the CD28.

The ratio of sail area to displacement is 15.24 for the 27 and 14.79 for the 28. So the 27 has comparatively more horsepower, which, combined with 1,500 pounds less displacement, makes her nimbler around the buoys and quicker to convert puffs of wind into hull speed.

The 27 is comparatively beamier than the 28. The ratio of beam to waterline length is 2.35 for the 27 and 2.5 for the 28. That gives the 27 more initial stability.

There's not much difference in the ballast ratios, but once again the 27 has the edge with 40 percent vesus the 28's 39 percent.

Neither the 27 nor the 28 have particularly efficient keel shapes, but both boats have a draft of 4 feet, so the 27's keel, on a shorter waterline, has a better aspect ratio. Yould expect a deeper keel on the 28, a boat with 2 feet more on the waterline.

The 27 is also interesting because it is a really heavy displacement cruiser with a Displacement to LWL ratio of 419, compared with only 367 for the 28. This means that comparatively more of the 27's displacement is carried under water, and that in turn means comparatively less windage to hamper the boat on windward legs and comparatively less superstructure for waves to damage in storms.

This heavy displacement ratio of the 27 also induces a substantial amount of inertia, which translates to resistance to capsize in breaking waves and also to ease of motion at sea. In fact, the 27's extraordinarily high comfort ratio, at 30.08 is almost the same as the bigger 28's, at 31.41. It would be hard to notice the difference under way.

In summary, the 27 is one of Alberg's latest designs and shows a sophisticated combination of speed, handiness, interior space, seakindliness, seaworthiness, and ultimate stability. For thousands of dollars less than a 28, it represents very good value for a couple or a small family.

John Vigor

[GB]

How big of an issue is the larger cockpit size of the 27(as far as safety)? I'm going to look at 27 for the first time tomorrow (I have not seen a 28 in person yet). The two other types of boats that I have looked at length are a Cape Dory 30 and a Pearson Coaster. The 30 is way out of my budget. The Pearson Coaster will needs some work. John as long as I mentioned the Pearson Coaster, how do you feel about how it compares to the Cape Dory's performance wise and such?

Thanks

[John Vigor]

Ideally, the CD27 cockpit is a bit large for deep-sea work. It was designed for coastal sailing and weekending, when a larger cockpit is a comfortable asset. But it doesn't mean the 27 is unseaworthy.

If I were planning an ocean crossing in mine, I'd fill some of the space with a built-in plywood locker. Alternatively, I could find place there for a liferaft or inflatable dinghy. In really bad weather, I'd fill it with sailbags--anything to reduce the volume that would otherwise fill with water. My 27 has two nice big 2" diameter cockpit drains, but I would have to find a way to waterproof the locker lids, because they'd let a fair amount of water go straight below if the boat was pooped.

The sturdy bridge deck adds greatly to her seaworthiness, and I don't think the size of the cockpit is a big issue if you understand its limitations and the problems that can arise if it is swamped.

I don't know the Pearson Coaster, but I see it's a William Shaw design and even if it dates from 1966 it will be a good cruising design, paying no attention to the sillyness of the International Offshore Rule.

The Coaster has more beam and interior room than the CD28, her draft is 7" deeper, which should make her better to windward, and she looks refreshingly workmanlike. She is pretty, but I would carry storm shutters for the four larger portlights in her doghouse if I were going to sea.

The Coaster came with the Atomic 4 gasoline engine, which might need replacing by now if it hasn't been already.

Cheers,

John Vigor

[Dick Barthel]

John,

Your posts are very illuminating and demonstrate again why you are such a great asset to our board.

Dick

[John Vigor]

Hi Dick:

Thank you for your kind words, but my expertise is as nothing compared with the combined knowledge of this board and its experienced individual members.

I get involved in something now and then, but mostly I just sit back and marvel at all the sound advice that surfaces in the various esoteric discussions, and the friendly manner in which it's offered. The tone and civility of this board is really quite astonishing. It's a wonderful tribute to its members and those who organize and moderate it.

Cheers,

John V.

[Stan W.]

No one else having stepped forward, I guess I'll assume the role of the loyal opposition. These are just my quasi-scientific opinions and you won't hurt my feelings if you prove them wrong.

The 27 came into production two years after the 28, so one can surmise that Carl Alberg learned how to improve on the 28 in that time.

What about the 25D and the 26? They are newer designs than the 27, but they have much lower D/LWL ratios and slightly higher LWL/Beam ratios. Also, CD continued making the 28 for several years after it stopped making the 27. Using your logic, should we surmise that Alberg and CD viewed the 27 as an evolutionary dead-end?

The ratio of sail area to displacement is 15.24 for the 27 and 14.79 for the 28.

This is true. The 27 does have a higher SA/D ratio and, therefore, all other things being equal, the 27 will be the faster boat in light winds. Of course, in the real world, all other things are never equal.

So the 27 has comparatively more horsepower, which, combined with 1,500 pounds less displacement, makes her nimbler around the buoys and quicker to convert puffs of wind into hull speed.

The SA/D ratio (horsepower) already takes displacement into account so, when you say horsepower plus less displacement makes the 27 nimbler, you are double-counting.

The 27 is comparatively beamier than the 28. The ratio of beam to waterline length is 2.35 for the 27 and 2.5 for the 28. That gives the 27 more initial stability.

I have never heard of anyone using LWL/Beam to compare form stability. LWL/Beam typically is used as predictor of potential speed with a higher number being indicative of more speed (a long thin hull is faster than a short fat hull). What you are saying is that the 27 has more form stability in proportion to its LWL, but it is total stability, not proportional stability, that matters. Simply by virtue of its larger size, the 28 has more total stability. In any event, these boats rely mostly on ballast for stability and, as you noted, the ballast ratios essentially are identical.

Neither the 27 nor the 28 have particularly efficient keel shapes, but both boats have a draft of 4 feet, so the 27's keel, on a shorter waterline, has a better aspect ratio. Yould expect a deeper keel on the 28, a boat with 2 feet more on the waterline.

These keels only barely qualify as wings and it is meaningless to compare small differences in aspect ratios when both aspect ratios are <1 to begin with. The 28’s longer keel will generate more lift, but it will also generate more drag. My hunch is it’s a wash.

The 27 is also interesting because it is a really heavy displacement cruiser with a Displacement to LWL ratio of 419, compared with only 367 for the 28. This means that comparatively more of the 27's displacement is carried under water, and that in turn means comparatively less windage to hamper the boat on windward legs and comparatively less superstructure for waves to damage in storms.

It is ballast ratio, not D/LWL, that best indicates how much displacement is below the waterline. In fact, the 27 carries proportionately more of its displacement above the waterline in its longer overhangs. However, windage is another case where it is the raw number, not any proportion, that matters. Simply by virtue of its smaller overall size, the 27 should have less total windage and, all other things being equal, that should give it an advantage sailing to windward in moderate winds.
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[Sea Hunt]

Mr. Vigor:

I very strongly echo Dick Bartel words. It is such a pleasure to read your posts, as it is with all of the CDSOA posters.

Your thoughtful, insightful, and interesting comments are very much appreciated, particularly by us “newbies”.

Mr. Bartel:

I also thank you for your thoughts, particularly as related to my efforts to someday own a Cape Dory sailboat. I shall cherish the day I am no longer a “hunter” of Cape Dory sailboats and can stand among the few, the proud, the “owners” of a Cape Dory sailboat. Hurraahh!!!

Fair winds,

[Oswego John]

Sea Hunt

Ooohrah to that.

O J

[John Vigor]

No one else having stepped forward, I guess I'll assume the role of the loyal opposition. These are just my quasi-scientific opinions and you won't hurt my feelings if you prove them wrong.

Stan, I wouldn't deign to try to prove you wrong. You are precisely the kind of contributor I was talking about in my earlier post, one of the extraordinarily well informed members of this board. I am humbled by your knowledge.

That said, let it be noted that there are very few absolutes in the sailing world. Eventually, it all boils down to opinions and experience. I gave my opinions and you've given yours. Caveat lector. Let history be the judge.

But just in case history isn't paying enough attention, let the record show that you did make one at least one big mistake. You chose a 28 instead of a 27. Could it be that you also let your prop freewheel?

Cheers,

John V.

[Stan W.]

But just in case history isn't paying enough attention, let the record show that you did make one at least one big mistake. You chose a 28 instead of a 27. Could it be that you also let your prop freewheel?

You'll laugh, but the main reason I bought a 28 instead of a 27 had nothing to do with sailing qualities. I just thought it would be a good idea to have a door between the head and the v-berth and I understood that 27s didn't have one.

You'll also be gratified to know that I am a prop locker.

[Sea Hunt]

Oswego John:

Thanks. I never could spell good. I assume you got the correct spelling from Lt. Gen. "Chesty" Puller. We need more like him.

Robert

[John Vigor]

Stan, you didn't have to go to a 28 for privacy. My 27 has a beautiful teak door between the saloon and the head, and another between the head and the V-berth.

It also has the Westerbeke 13 hp diesel, a built-in bronze bow anchor roller, and a recessed anchor locker set into the foredeck, all of which were standard on late-model 27s.

Glad to hear you're a prop-locker, though. I find people who lock their props are a much superior breed.

Cheers,

John V.

[Oswego John]

Prop-Locker: n. Place to store the prop. (prahp loch-arrgh)

Hope this helps,
O J