What to expect from c-dory hull?

A

Atomic_adam

New member
Hi everyone. Took my 14' out on the water today. Noticed something that I'm sure other people have experienced and could enlighten me on.

-35hp Johnson with hydrofoil-
-cavitation plate is even with bottom of hull-

I found that at speed (28mph) that when i went to make a slow turn the boat basically rolled a bit and then decided to turn or felt like it grabbed. I also found that depending where people where sitting and trim level that the boat actually felt like the stern was coming loose and would move side to side a bit. I have driven a few different boat and this is a new experience for me. I was thinking that this is all a function of the C-dory hull design and that they are more of a cutting style hull. What sort of behaviour should i expect from my boat? Is this hull not meant to travel at that speed?

Cheers Adam
 
I think you are experiencing bow steering, where the bow decides where the boat is going to go, not the rudder. At high speeds this can be a problem because the bow has a bigger area than the rudder and the turns can be sharp and unexpected. You may not be able to stop the turn with the normal steering system.

At high speeds the bow should be up a bit so that the boat is running on the planing part of the hull. If you can't ride comfortably with the bow up, you are probably going too fast for the conditions.

You can also experience bow steering at medium speeds if the bow goes down (e.g. at the bottom of the backside of a wave).
 
Happened to me to when I first got my c-dory. Coming from a deep v boat the 28 mph seems like a normal speed to travel.

It is a bit too fast for a C-Dory. Maybe trim you engine up a bit. These boats are meant to run at 20 mph with a top speed of maybe 25 mph. Once you get used to the hull you will like it.
 
Agree bow steering--motor trimmed down too much, and maybe weight too much forward. The foil can actually accentuate this. The foil will also get the stern up faster on a plane. The boats start to plane at 9 to 10 knots, and are usually driving at the high teens to mid 20's for cruising speed.

If you have any weight in the bow, you may want to move it aft. Keep the trim mid range.
 
I noticed on Journey On, a 25, one has to trim the bow up when you get to about 18 knts, if you want to go faster, say 25 knts. So I put the trim tabs down to get on plane and the up after about 15 knts.

Not a clue as to how this compares to a deep-V. The only 2 power boats I've owned are Journey On and an Achilles dinghy.

Boris
 
Thanks everyone for offering advice. I think I'm expecting something that isn't possible with a c-dory style hull. (And not in a bad way). I was trying to get the bow down like a flatter style speedboat. I'll have it out again soon and try to bring the bow up. And at mid range on the throttle. It's not like I'm in a rush. Haha!
Thanks again.
 
Uh 35 hp on the 14?! Thats max rated and more than needed for an 800 lb boat. We run 70-90 hp on the 22's. With your power you are a test pilot at wot. She'll tend to be squirelly at the top end. Keep weight out of the bow tell people not to move around. Turn careful like. Good luck.
George
 
Have had the same happen on my deep V stern drive with the difference being you also get a severe tilt into the turn. Since mostly all you read about is getting the bow down, it's good to hear about those situations when you need to get the bow up some on a C-Dory.
 
I went with a 35hp on the boat because that was the max rated for the boat. At about 165lb it is the same weight as most 4 stroke 30hp outboards which are common on the 14' Dory's. Now that I'm armed with some information about how the hull should ride and "APPROPRIATE SPEEDS" :smilep for said hull it'll be good. Personally I would rather have the HP and not use it rather than not have it when needed.
 
like said above it was a big transition for me coming from a deep v. and keeping speeds down, the surfing took me over a year to get comfortable with but you will like it once you get used to the hull...
 
35 hp on a 14, even, a C-dory is an accident waiting to happen. So, use real caution and keep that size boat 20 mph or lower. A 20 hp would have had you screaming along just fine. But you have the motor you have, so just manage your speed, other wise, you could easily end up swapping ends in a turn, particularly with any wind chop.

My comment has nothing to do with hull shape, but rather with too much HP on any 14 foot recreational hull shape.
 
Thanks everyone for the advice. A lot of knowledgable, and thoughtful people on here. Will be using caution as I figure out the ins and outs of the new boat.
Cheers
 
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