C-Dory Handling

Swampthing · Posted: Sat Sep 17, 2005 3:27 am Post subject: C-Dory Handling

I recently acquired a 1985 22 Angler with a same year 70hp Johnson. Motor runs Ok and the boat is very well off in calm waters, but when we hit a cross wind or a little chop (2 feet or so), we have a very hard time keeping the boat tracking along a straight line. Not always to the left or right, but wherever the wind or waves want us to go.

Has anyone ever put a keel or system of small keels on the hull to keep the boat tracking straight? I hear that people like putting trim tabs on, but I have serious doubts as to whether this will help at our working speeds of 4-6 knots.

Sean
San Francisco Bay

Sea Wolf · Posted: Sat Sep 17, 2005 5:18 am Post subject:

Sean-

Here a link to a previous discussion on this very topic:

http://www.c-brats.com/viewtopic.php?t=896&highlight=keel

Let us know if you have further questions! Joe.

flapbreaker · Posted: Sat Sep 17, 2005 12:12 pm Post subject:

I'm curious since I don't yet have a c-dory is this normal behavior? Did they change the design since 1985 for better tracking?

Sea Wolf · Posted: Sat Sep 17, 2005 1:55 pm Post subject:

flapbreaker-

The "Classic" or original CD-22 (1979-1986) had an Angler (smaller) sized cabin with a simpler interior, and the hull bottom was absolutely flat from a little bit below and behind the bow entry to the stern. It looks like a clothes iron's bottom surface. Absolutely flat with a nice curved border on the sides starting at the front on both sides and symmetrically ending at the perpendicular transom. It was cored with marine plywood instead of the small balsa blocks that are required for the compound curves in the 1987 and later models.

During the period from 1979-1986, they apparently added keel strips to aid in tracking, as described in the link above. It would appear also that an evolution of different configurations took place.

Someone with that model of boat and an interest in the subject could probably contact a number of different owners of these models and definitively trace the step by step changes, although what really matters is that if you have one and you don't like the way it tracks, you can get several ideas on how to change it, including the last, and even improve upon it if you like.

Adding keel strips, might, however, affect how the boat loads and rides on the trailer and may therefore require changes to that vehicle. The original trailers on these Classic models usually have a single large full beam width roller at the rear of the trailer for entry and support.

The transom in these boats is also different in that the engine well is small and centered, with open space along the sides and a shelf/brace part way down that braces the well to the sides of the boat. I think these boats will only accommodate a single large engine, not twins. A kicker will work with the big engine just fine, however, if mounted outboard to one side or the other.

Red Fox has a "Classic" CD-22, although it's been modified about as much as an ex-Greyhound bus turned into a motorhome. Maybe some of our other members can suggest a few photo albums that will best illustrate the original classic hull, deck, cockpit, transom, and interior.

Joe.

Redƒox · Guest

Swampthing · Posted: Sat Sep 17, 2005 3:21 pm Post subject: Re: C-Dory Handling

Thanks to all who replied. Although my CD is stated as an '85, I don't think it has a keel at all (i.e., it is a totally flat bottom). And upon thinking about the trailer, if it did have a couple small keels, they'd be ripped off the first time I put it on the trailer. If I get a chance to change the trailer I'll probably try to put a couple small and long keels on as the link provided earlier suggests (http://www.c-brats.com/viewtopic.php?t=896&highlight=keel ). I wonder if there is a premade stainless keel available?

In the mean time I wondering if there's a way I can mount removable 'over-the side' keels for motoring at slow speeds (< 6 knots) only. I'd definitely have to make them a breakaway item as I don't want to rip the gunnel off the boat, to which it'll be attached. By the way, I've had great sucess making removable mounts for other over-the-side applications that clamp to the gunnels. Very sturdy and easy. If I could post a picture I would, but I'm at a loss to figure out how.

I'll also experiment with more weight in the back. We had about 300 pounds stored back there. I wonder how much more to add?

I'm not worried about the seawothyness of the vessel as she feels and sounds stable, but try to keep her on a straight line with the GPS and it's a bear. And it seems the slower we go, the worse the handling is. 2-3 knots is worse than 5-6. And the worst situation is having the chop or small swell hit the stern corner of the boat. It just swings her around again and again - I almost think the boat is too light.

Swampthing · Posted: Sat Sep 17, 2005 3:58 pm Post subject: C-Dory Handling

I posted a pic of the over-the-side mount in use here:

http://pg.photos.yahoo.com/ph/seanavent/detail?.dir=f37d&.dnm=507b.jpg&.src=ph[/url][/list]

Swampthing · Posted: Sat Sep 17, 2005 3:59 pm Post subject: C-Dory Handling

Try this instead:

http://pg.photos.yahoo.com/ph/seanavent/detail?.dir=f37d&.dnm=507b.jpg

rogerbum · Posted: Sat Sep 17, 2005 9:34 pm Post subject:

I was kind of wondering if you could do something more like one sees on sea kyaks - e.g. a real keel (or in your case two) that is hinged and can be lowered/pushed down with a cable. I'm imagining two keels that would be mounted on the transom that would be lowered a good bit into the water. That would allow you to pull them up for trailiering. This might help with the tracking issues.

However at realy low speed, I'm not sure too much can be done about the problems you're describing. There's a lot of boat above the waterline and not much below it and the wind will push it around pretty quickly.

Redƒox · Guest

Could not spot a kicker on her, and that 'over-the-side' contraption is funny!! Xmas Naughty

I think almost any "flat-bottomed" boat, needs a lot of weight on the transom, to help off-set what you may add in the cabin (peep and gear mostly---lots of goodys to! Smile

)
For me, one of the best reasons for twin-engine, or a big bad four-stoke is the fact the weight is a much needed thing Idea

Myself; I have big-bad-Yamaha F-115, and the 8hp Yami' kicker (extra-long-shaft with tiller and the whole nine-yards that weighs (on my scale) 118 pounds Xmas Eek

just what the old girl needs---permanent part-of-the-boat weight, where it's needed... should you want to carry weight forward. I don't see how you can avoid this, if your equipping for any length of time out there Love

If you can't re-fit her with nice heavy engines... at least try to get a kicker on there (minimum-weight --- about 80-pounds) add another battery back there. Far as fuel for weight... fuel does not count, it has a way of disappearing Rolling Eyes

"keel" personally; I think the one on the main-engine is a hell-of-a-keel Idea

If there is any "tracking problem" apparent in the old Classic; I am thankful for it Idea

personally, I believe there needs to be some amount of "slippage" or "give" when your beam-to in some big waves Smile

Many trips sluggin-it-out to get home in RedFox, reveals the bow-down attitude, only lets the bow get pushed-around by the waves Crook

~~~hope all my "advice" didn't make-ya-mad ... Xmas LOL

Sea Wolf · Posted: Sun Sep 18, 2005 3:34 pm Post subject:

Swampthing-

Greg's (Red Fox) analysis of the lack of stern weight being a major contributor to your handling problems would be the easiest thing to check by simply adding some temporary ballast to see if it changes your handling problem. It may well be that your stern is setting to high in the water to dig the chines in properly to the rear to balance the immedrsed bow's tracking effect up front.

In a similar manner, some fast dinghy catamaran sailboats don't even have keels, but rely on sharp chine corners to provide resistance to sideslip, some even having asymmetrical hulls.

If you want to go further, the easiest next step would be to get a Permatrim hydrofoil to mount on the cavitation (anti-ventilation ) plate.
The Permatrim has downturned side edges and would be an assist in tracking.

One could easily build an exaggerated foil of this time to increase the effect, although at high speeds, too much side foil and you might induce other handling problems.

This would certainly be an easier solution that trying to modify the hull or build an elaborate set of side boards, drop keels, centerboards, etc.

Any serious modifications to the boat or hull that could not be removed would negatively affect your potential resale value from most prospective buyers, who are cautious by nature as they shop.

Keep in touch! Joe.

Redƒox · Guest

k3nlind · Posted: Tue Sep 20, 2005 9:33 am Post subject:

Redfox wrote:

Salmon Slayer · Posted: Tue Sep 20, 2005 11:27 am Post subject:

As the owner of an 81 Angler in Alaska, I can vouch that RedFox is spot on about the weight towards the stern affecting handling. My wife an I use our boat as a "movable cabin" and we sometimes carry a lot of stuff.

We have a new 4 stroke 90hp Suzuki and a 9.9 Johnson kicker and I usually carry about 74 gallons of fuel when full. We boat in all types of weather and it is almost always windy here and we have had no trouble at all with tracking.

Do you have the beaching strakes on the bottom of your hull? If not I suspect that could be part of your problem. I have owned sail boats up to 33 feet, power cruisers, a diesel trawler, and various skiffs and this is by far the best boat I have ever had. Small on the outside, big on the inside, and a simple bulletproof design.

Redƒox · Guest