Do the chine walk

Sorry guys perhaps a little bum steer from me with my opening question but all your opinions are helpful in focusing my mind which I sometimes find difficult to do on my own :confused:

What I believe I am actually suffering from is prop torque so the boat has a tendency to ride on the port chine. The boat is ok at displacement speeds then get over the hump and over she goes to the port side. As I also said using the trim tabs alleviates this however if i change direction or wind gets up or someone dares to move then I am back playing on the tabs. After getting on the plane I always trim the outdrive out looking for that sweet spot that gives me best revs and economy so I don't think I can do anymore on drive trimming. Its not a new problem to me as I have owned the boat for 5 years, I have re-propped once with the current prop giving me blistering performance (compared to my previous prop) but the additional torque from the 4 blade prop has not helped the problem not that I expected it to as the exercise in repropping was to get better performance.

Also there is another boat the same as mine in our yard without trim tabs. He says he has no problem with listing. He is running a Volvo outdrive with duo props it's this that planted the seed in my mind. As I said I am not overly worried about the expense and know changing the drive would not make financial sense but I do now intend to keep the boat for a few more years,I just want the boat to put a bigger smile on my face :) Also with my original drive approaching 10 years old I would be comfortable changing for peace of mind and the new warranty.

Perhaps I am overly fussy but if my screen isn't level with the horizon it annoys me partly due to being in construction and obsessed with levels :rolleyes:

I know the answer really, I need to get out on the other boat then decide.

Thank you all for your input it really is much appreciated

Martin
 
oldgit said:
More to do with hull design/size than drive.Poss high engine power torque verses size of boat.Torque givng the list simply due to the small hull volume less able to resist the prop force acting apon it.?
Click to expand...

I think this sums up my problem 250hp with a large 4 blade prop on an 8 metre boat with 22deg deadrise....does this make sense?
 
Your problem is exactly the same as mine - fine at displacement but as soon as I start up on the plane it lists to the left.

It's worse some times more than others and there doesn't seem to be any rhyme or reason. You can list to the left, slow down to displacement and then get back up on the plane and it'll be fine.

It's something I think I'll have to get used to - I always forget to trim the leg up slightly once planing so I'm hoping this coupled with better use of the trim tabs will overcome the problem.

Just out of interest MOP, what boat do you have and does anyone have a rough estimate of cost to change to a Bravo 3 drive?
 
moonraker 36 said:
would check possable play in leg.
could poss be worn gimble housing.

this chap had simular prob turned out it was the gimble.
http://www.ybw.com/forums/showthread.php?t=264246
Click to expand...
The gimbal bearing was renewed about 2 years ago and the drive serviced in may last year, I would hope the engineer would of told me then if there was a problem with the housing. I will check for play over next week end

Martin
 
I've got a friend who lives in Chine Walk. It's in Ferndown - sorry, contributes absolutely nothing to this thread but it's always tickled me.
 
maverickofpoole said:
I will check for play over next week end
Click to expand...
Nothing wrong in checking for play of course, but even if you would find some, I can't figure out how that could have anything to see with the behaviour which you described.
That's a plain vanilla prop-driven listing, and as already discussed has nothing to see with chine walk/riding.
Besides, also the problem described in the old thread linked by moonraker has nothing to see with yours, as I understand it.
 
If we assume the problem of OP as listing instead of chine walking, can be cured by an autopilot.

My boat is 9,47m LOA and 8,69m water line with single VP KAD300 DP-G drive.
While underway even the load distribution is fair, boat tends to list when wind/current/wave plays their role.

I didn't installed the autopilot for this reason, for comfortable long runs. But discovered that activating autopilot corrects the listing and eliminates the need of using trim tabs.

My boat runs as flat as possible when the ap is activated in any load and sea/weather conditions.

HTH.
 
I recall seeing chine running cured in a RIB (6m with 150HP) by offsetting the outboard to one side. (It also helped it fly straight..)
I appreciate thats a difficult modification to make to an outdrive boat.
 
Hi Martin,

I can confirm that I have exactly the same phenomen with my Karnic 2660 similar model like your but hull 2ft longer, and twin outdrive instead of single.

I think this is a result from the hull shape / weight distribution of the boat
These boats have a very small beam, and a still a pronounced V at the stern.
I can easily correct this listing with weight distribution (guests moving to the other side) or more appropriate with the trim tabs,
But just like you, the permanent re-trimming I find rather annoying,
Therefor I always’s asc my guest not to unnecessary move their position on deck while we are on the plane.
My boat has always’s been listing more to SB side, not Port, and in my case the boat is a bit more heavy on that side, (the captain is rather heavy ;-))
When I place more guests or dive gear on SB side, the boat behaves more level.

Also, I think the hull shape is not designed to have very high speed,
My cruising speed is around 25kn, but can easily go over 30kn, (wot is 38kn)
But then the boat behaves very unstable, I seems like only a small mid segment of the bottom is touching water at high speeds, boat is very high above water surface, so very sensitive for left or right listing.

Imho you can’t improve this with another outdrive, I have a completely different drive system, but a very similar behaviour.
And I can confirm NickH’s observation that automatic trimming isn’t a improvement, did some test some years back with it, but didn’t bother to use this any more.

I have a twin engined single prop counter rotating setup, so I can't believe this has anything to do with prop torque either.

did you try placing more weight on one side ?

my boat had extra lead sheats in the bottom, for ballancing the weight,
I took this out, when I had placed a heavy invertor on that side,
I should place some extra weight back in, to level her better,but I preferred not to do so, to keep the (trailable) weigh as low as possible.
 
MapisM said:
Nothing wrong in checking for play of course, but even if you would find some, I can't figure out how that could have anything to see with the behaviour which you described.
That's a plain vanilla prop-driven listing, and as already discussed has nothing to see with chine walk/riding.
Besides, also the problem described in the old thread linked by moonraker has nothing to see with yours, as I understand it.
Click to expand...

just trowing ideas at the problem..not trying to say 100%gimble fault..but maybe worth just a quick check.
 
Bart that's really good feedback from a fellow Karnic owner and much appreciated. If you have the listing problem (albeit opposite hand to me) with contra rotating props then my changing to duo props will probably not have much effect. Interested in the ballast on yours, did you put this in or was it there from new? I might get some extra concrete delivered on my next job and fit that ;) only joking but I might try ballast of some kind.

Interesting about the high speed. I cruise max at 25knots but usually around 20/22knots with wot being 32.9 knots (don't forget the .9 :D). she feels happy at these kind of speeds. I also find that full tanks help give a better ride ie planted more firmly on the water.

Melida
If we assume the problem of OP as listing instead of chine walking, can be cured by an autopilot.

My boat is 9,47m LOA and 8,69m water line with single VP KAD300 DP-G drive.
While underway even the load distribution is fair, boat tends to list when wind/current/wave plays their role.

I didn't installed the autopilot for this reason, for comfortable long runs. But discovered that activating autopilot corrects the listing and eliminates the need of using trim tabs.

My boat runs as flat as possible when the ap is activated in any load and sea/weather conditions.

HTH.
Click to expand...
Melida

Thanks for the suggestion but we already have an AP along with far to many other toys all very overkill for an 8 metre boat but I do love toys :)

GOG
I've got a friend who lives in Chine Walk. It's in Ferndown - sorry, contributes absolutely nothing to this thread but it's always tickled me.
Click to expand...

Oooh very posh and my sense of humor :cool:

Martin
 
Last edited:
I used to have a 18ft Phantom with a 200 merc. out board. At 50mph + it didnt chine walk but more like chine sprinted. This was eleviated by flooding the bow tank which put more keel in touch with the water and allowed me to power on up to about 60. Only on a flat sea unless it would snap over from one trim to the other. Incontinance pants were mandatory. Dave.
 
maverickofpoole said:
Interested in the ballast on yours, did you put this in or was it there from new?
Click to expand...

I took out the "wall's" in the mid cabin (towards the stern), to see what was behind, and to find a empty space for placing a big invertor.

then I discovered on the hull bottom on Port side, there was 35kg of sheets of lead, (originally fitted by the factory) which I took out, and installed a invertor (20kg) just above that spot, below that seat / cockpit locker on P side.

Some time later I installed a extra fridge compressor underneath the locker behind the helm seat (SB side)
I placed isolation foam around that locker from underneath, and converted this to a extra drinks fridge

the boat got a small list to SB side since then.


Yes, I want to know and see every hidden space in my boat, and eventually use it for something.
still some spaces left for exploration in Blue Angel :)
 
maverickofpoole said:
Thanks Bart

I think I will be removing those same panels in mine just to see if I have the same hidden ballast and maybe move it about. You never know it may well be a cheap fix for me :) but then again knowing my luck :rolleyes:

Martin
Click to expand...

even if there is "nothing" you could try placing some weight in there
yes some concrete would do the job :)

the lead sheets where curved over a stringer and glued on top of each other iirc
 
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