Rough Riding 16' Cruiser in Chesapeake Bay chop

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DoryLvr

New member
After 5 and a half years of looking at C-Dorys, I am finally a new C-Dory owner (today was the first day to take my 16' Cruiser out!) However, I was surprised at how rough the C-Dory rode in the Chesapeake Bay chop. I also own a 15' Hobie Power Skiff and it flies through and over the chop pretty smoothly. I am assuming it is because the C-Dory is flat bottomed with no insulation. I found today it rode much better at about 8-9.5 knots than wide open (it has a 50HP Yamaha). Is this a normal observation or am I not trimmed out properly? What is the best speed for running these boats in chop and smooth water and are they normally pretty noisey when running (the fwapping of the water under the hull)
 
The C dories have very little deadrise (almost flat bottom) and will pound in any significant chop. If you put the bow down, it will alleviate this to some degree.

On the other hand, the Hobie Power Skiff has considerable deadrise--it is described as a "deep V" and to my recollection has about 20 degrees of dead rise vs 2 - 4 degrees for the C Dory line.

When one buys into the C Dory family they have to realize that they run best at lower speeds in chop--but that they do plane at low speeds, and a hand on the throttle, as well as on the helm will allow you to work the boat through the chop, by going a bit off hitting the waves head on.

Enjoy your boat.
 
It's pretty normal for the C-Dory boats to run rough in chop. The flat bottom is great for fuel economy and not so great for chop. As has been said many a time on this site, all boats are trade offs and the trade off of a dory style hull is fuel economy and stability (in flat water) against a rougher ride in the chop. That said, getting the bow trimmed down some can really help. With a 16, you can do trim tabs but most here have been very satisfied with the improved bow trim afforded by permatrim fin mounted on the main engine. Nonetheless, going slower is the primary answer for dealing with chop.
 
Get a permatrim it will make a remarkable difference in performance on the 16. I found that for beam to beam trim a cooler in the back simply handled this by sliding it side to side but the trim tabs work well also for additional $. And has been said trim the bow down slow down and enjoy the ride. Instead of plowing thru the seas like a deep vee the C-Dory just bobs over like a cork. A canopy over the back of the cabin will help some with the motor noise and I'm told the spray on mascoat insulation in the cabin helps also.
 
What you are experiencing sounds similar to my 16'. The permatrim has made a big difference however. Slowing down is required when the chop starts to get up to about 2'.
 
16 cruisers tend to be stern heavy. You should do everything you can to get the bow down. It will do much better in chop in that attitude. The 16 angler has less weight to the stern and doesn't have as much problem in this area.
 
I have a C-Dory 16 cruiser (C-Nile) and use it mostly on Long Island Sound.

1) In 3' seas (I'm out there by mistake), it's rough going. Slam! Slam! Slam! We go 7 mph or less. We're going so slow, that the boat is not easy to control. A permatrim would probably help, but I'm afraid to install one for fear of negating my 6 year warranty.

2) In 2' seas or more, we stay home. Again, the boat is plenty safe, but we have to go less than 11 mph with the motor at full trim

3) 1' to 1.5' is normal, and we do about 15 mph with full trim

4) Less than 1' -- 5,400 RPM, slight trim, 22 mph.

The CD 16 is a slow boat, and gives a rough ride at high speeds. However, my wife and I are not on the water for speed, and we placed safety above all other factors. We feel very safe in this boat. In an earlier communication, I detailed how we went through 5-foot standing waves (foolishly). It was harrowing, but we made it safely while a lessor boat would have broached and perhaps inverted. So, we lived for another day, much wiser and vigilant to avoid such circumstances like that in the future.
 
I seriously doubt that the Permatrims will affect your warranty. I have had them on my Yamaha 150s almost from the get-go and they have never been a factor in my warranty claims.

Warren
 
Our boats can handle a lot. The pounding is uncomfortable so I slow down to where I don't slam so hard. Going into the swell is always going to be slower due to the pounding but running with it should be smooth.

I run in the ocean, so often when I boat, the swell is minimum of 6ft. With wind and chop running into it I will stay alert with throttles so that when going over the swell I have slowed down and then when going down the back you can accelerate again. Again engine trim helps smooth the ride.

As to weight, I believe to much weight forward will increase a boats tendency to broach. I run in the ocean where surfing a swell is part of the fun. I will keep my load balanced and biased towards aft. I like to have clean shorts on and poking my bow into the trough of a swell will have me making a mess.
 
c-nile, you need the permatrim, or at least some foil. I will even give you my old dolefin if you want, just pay for the postage. It works and I am sure even with it you would see a difference.
 
Warren, Tee Ten, Lucky Day Et. Al.:

Many people have been telling me to get the Permatrim. When I'm going slow in rough water, I can't get the bow down, and the boat sort of fishtails. After putting 140 hours on the motor last year, I think you all are right, and I'll install one this year.

Thanks!

Rich
 
Everyone is recommending the Permatrim by name. What do people think about some of the other hydrofoil products out there, dolefin, SE Sport hydrofoil, etc. They are supposed to do essentially the same thing. Reason I ask is that Permatrim seems to be a very west coast centric product. Also the availability of the others is very wide.
 
Not sure how helpful this will be as I can only speak to the Permatrim. It is the only kind I've used. Permatrims are specifically designed for your motor, they're not a one size fits all product. They are quite strong, easily installed and the design seems to work. They have been on my 22, (twin Honda 40's) for one year and have made quite a difference. People who have installed them on 16's seem to like them the most. I use them almost exclusively for fore and aft trim. My Bennett trim tabs are now just used for lateral trim. They are made in New Zealand but the dealer is in Wisconsin, (Shipyard Island Marina), and has been very good to work with. I think you will find several references to people who have had some other foils on their boats and have switched to Permatrims. I would contact Shipyard Island Marina and talk with them. Good luck.
 
I can personally say to me, there was a huge difference between the Doelfin and the Permatrim. Not sure why unless it is because the Doelfin has a lot more lateral lift but Permatrim gets theirs from increased length behind the engine. Permatrim wins hands down.
 
There is a "Bob's Machine shop" fin which is used on the East Coast. I have used the Doel-Fin on inflatables and aluminum sliffs up to 13 feet, and they worked fine there. But for a bigger boat, you need a bigger fin--more lift and more rigid.

The Doel-fin is plastic and flexible, I don't think it will have as much effect. The Permatrim is made "down under" but distributed by SIM--and used nationwide--plenty of them in Florida.
 
Cosmic C asks if there is a reason to put a Permatrim on a boat which already has trim tabs. We ran the C dory 25 for a year without Permatrims, although we already have Permatrims on the Tom Cat (which cannot easily use trim tabs).

I can say that for our boat, and our type of boating, it made a real difference. We were able to get the bow down much further and drive it through the chop with less or no pounding, in conditions where we had pounded with just the trim tabs.

We also found that it got us on a plane at a lower speed and improved the handling at the low speed planes.

I would put it on again.
 
O M G!!! I installed the Sport SE Hydrofoil on the engine yesterday. It is a shorter hydrofoil that extends out beyond the boat more than most. Kind of a combo between the permatrim and a dolefin. (See pics I am posting under DoryLvr) Took the boat out today. Wow what a difference in the chop. It planed so fast and at a low speed. The speed to RPM ratio was wild, I picked up a lot of speed per RPMs and was cruising at 14.7 knots with only 3000 rpm. And smooth, hardly a bump at all. Thank you to all for your input. Problem solved! :D
 
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