New to cruiseres and have a question

[snmpgh]

Hi, new to the boards and new to cruisers. I grew up on 18 and 19 ft runabouts and was used to how they handle and steer. I just purchased a 26ft Regal Commodore 256 (1994). It has the Mercruiser 5.7 with the Alpha 1 outdrive. I only had a chance to do a prolinged test run before the boat was pulled and winterized (my boat mechanic checked it out and pronounced it sound, he is an old family friend and would not steer me wrong). The only thing I noticed was that at slow cruising speed (below 15 mph) the sterring was fairly loose and you had to saw the wheel back and forth alot to stay reasonably straight. At speeds over 15 mph, the steering was nice and tight and responsive.

Is that typical of cruisers? Or do I need to have the steering linkage checked out next year?

Thanks

Mike

 

[MikDee]

Re: New to cruiseres and have a question

Yes, some degree of wander is to be expected, especially the larger the boat, but check your steering linkage for excess play, or slack, anyway to be safe. Another thing you may notice is a lean to one side, or the other, when under way due to the usually deeper centrally located deep vee bottom, adjustable hydraulic trim tabs are a necessary item to correct this, also at low wake speeds putting both these down usually helps with wander.

 

[txmntman]

Re: New to cruiseres and have a question

funny thing....I remember having a 20ft runabout (4 Winns Horizon, nice boat) with a mercruiser 470 IO.....it would also wander at slow speeds. I will have to say that it was the deepest v I have ever had, and the only I/O I have ever had, but I have seen no wander charateristics with my bay boat center consoles, or bass boats.....all have been flatter bottomed and all have been outboard, but I do believe the problem to be more of a factor of the deep v than the I/O....

 

[QC]

Re: New to cruiseres and have a question

What he said ^^^^^ (MikDee) with the following observations

he is an old family friend and would not steer me wrong

Considering the topic that struck me as funny . . .

The only thing I noticed was that at slow cruising speed (below 15 mph) the sterring was fairly loose and you had to saw the wheel back and forth alot to stay reasonably straight. At speeds over 15 mph, the steering was nice and tight and responsive.

If this is literally true I think you have another problem. I would be very surprised if you saw traditional "wander" above even 8 miles per hour. Wander is usually only evident close to "hull speed" which, in my opinion would be even less than 6 or 7 miles per hour in that boat. Just double check, if she literally wanders at say 12 MPH (GPS no current) then you have another problem.

 

[scoutabout]

Re: New to cruiseres and have a question

I agree - wander at low speeds is common on many larger boats. My dad's 25 ft Chris Craft did the same thing. I would also agree with QC that any real forward thrust above 5-6 mph should eliminate the wandering. If not, then go looking for something else -- loose steering gear, bent skeg, twisted trim anode, etc. I've heard that a twisted or hogged hull can produce those effects too. Let's hope it isn't that drastic.

As for dealing with "normal" wandering, you will find that if you make small corrections at the helm (sometimes even no correction) she'll come back on course before wandering off in the other direction. The net result, though, is a more or less straight course. What you want to avoid is chasing her in ever-increasing corrections. It's tiresome and usually just gets worse until you find you're sawing back and forth like a mad fool.

 

[jonesg]

Re: New to cruiseres and have a question

It sounds very similar to what happens with airfoils, if the leading edge (wing tail or stab) is too sharp it causes hunting. Its a slight stalling from one side to the other.

Same thing is probably happening with a hull when the bow is sharp as with a deep V, it yaws from side to side naturally and should stabilize itself like an aircraft with plenty of dihedral. It would wallow a bit though.

Computerized independant trim tabs could fix that, coupled to a solid state gyro. Boat design is real good but boat technology seems way behind.

 

[scoutabout]

Re: New to cruiseres and have a question

Interesting theory, jonesg. I'm trying to imagine what the marine equivalent of extreme dihedral might be...And now that I think about it, I've never experienced the issue in any kind of sailboat -- large or small, centreboard or keelboat, under sail or power. I guess the added wetted surface perhaps presents too much resistance to being pushed off track.

 

[180shabah]

Re: New to cruiseres and have a question

Not very many sailboats out there that use a planing hull with 18+ degrees of deadrise at the transom.

 

[jonesg]

Re: New to cruiseres and have a question

Interesting theory, jonesg. I'm trying to imagine what the marine equivalent of extreme dihedral might be...And now that I think about it, I've never experienced the issue in any kind of sailboat -- large or small, centreboard or keelboat, under sail or power. I guess the added wetted surface perhaps presents too much resistance to being pushed off track.

I would , at a guess, say the sailboats are more directionally stable due to their aspect ratio, length to beam being far greater than powerboats.

 

[QC]

Re: New to cruiseres and have a question

Has seemed to be most evident with sharp entry and I/O . . . There are so many differences with a Sailboat hull, keel, rudder size, shape etc. etc. etc. Also . . . the force of the wind itself would keep the pressure on the rudder as opposed to a more neutral pressure on both sides that a boat being pushed from the stern would experience . . .

 

[MikDee]

Re: New to cruiseres and have a question

Actually I think the large keel ratio to the sailboat size keeps it from doing this, not necessarily the length to width aspect. I would say also because of this, a sailboat can't make as sharp a turn as a powerboat.

 

[fdmsiv]

Re: New to cruiseres and have a question

I would imagine the weight of the cabin makes your boat a little bow heavy. Add in a sharp V in the front and you are probably creating a turbulent flow at low speeds. Rudders/Outdrives need a clean smooth flow to be effective.

Once you hit the 12 knots or what ever it is, the bow rises and the flow to the rudder/outdrive becomes more laminar.