The boat that does not back up

[Portuguese]

Gentlemen:
I have an interesting case for your further appreciation, in fact, a mystery for me.
I friend of mine bought and used steel 48 fishing trawler. The boat is 18 years old and it has been trolling for shrimp. My friend turn it into a recreational boat, kept the tanks intact, changed the engine from a CAT to a Cummins, new furniture, same prop, nothing new or fancy that could eventually change the balance. As a matter of fact the boat sits leveled on the water with ¾ of a load. This past weekend, we took it for a first trial on sea. The boat went on the water last Wednesday afternoon and tied-up on a mooring until Saturday when we decided to sail with it. Here is the problem:
THE BOAT DOES NOT BACK UP IN A STRAIGHT LINE. She goes either side depending on wind or current. In a calm flat water day, which was Sunday, when in reverse, she went one side and then the other for no reason. The rudder is always at 0 degrees. I have never seen such thing! The boat was pulled out yesterday to a dry dock and nothing was detected. The rudder is perfectly aligned with the prop shat and the prop is the same as always has been. We dont know if this problem was already there on the previous 18 years as the boat was bought in a auction. The boat has no bow thruster; you can imagine the nightmare that will be to fit her in a pier slot.
Any ideas?
*
Thanks in advance

 

[Marin]

Virtually all single engine boats will not back straight because of prop-walk. Depending on the direction the prop turns in reverse (clockwise for a right-handed prop or counterclockwise for a left-handed prop), the stern will be moved sideways one way or the other by the prop walk. A right-hand prop will move the stern to starboard in reverse, a left-hand prop will move the stern to port in reverse. There is no cure--- it's the nature of the beast. Competent operators of single-engine boats quickly learn which direction the stern goes when the boat is reversed and they'll use this trait to their advantage while maneuvering or docking.

Other factors like current and wind can also affect the direction the stern swings when backing up.* They may reinforce the prop walk or they may counter or even overpower it.


-- Edited by Marin on Tuesday 23rd of August 2011 10:12:12 AM

 

[Vyndance]

What you describe is a typical single engine trawler. The effects in reverse are prop walk. The tecnique used to back up in to your slip is called back and fill. How was it going forward at slow speed? Most people with single engines do not back into slips. Easy enough to do but takes to much time. Take the boat to a open spot and just play with it.

 

[Tom.B]

Vyndance wrote:
Most people with single engines do not back into slips.

*Wait... WHAT? :-D

 

[jleonard]

*Most people with single engines do not back into slips.

That simply is not true assuming you are not including sailboats. I can back single into a slip better than most twin engine guys. That's not brag, it's just the result of lots of practise. You just need to understand exactly what your particular boat does in reverse, then plan accordingly.

*

 

[Woodsong]

If you figure out how to get a single screw boat to back up in reverse patent it ASAP b/c you will make a ton of $$$.

 

[Doc]

I always backed in with no problems at all. It was hard to get off the tug bow in.

 

[Woodsong]

No doubt a single screw can be backed into a slip but the question is can you get a single screw to go any distance in a straight line while reversing?

 

[Marin]

Woodsong wrote:
If you figure out how to get a single screw boat to back up in reverse patent it ASAP b/c you will make a ton of $$$.

*It's dead simple.* You use the boat's intertia and transmission to keep the boat moving in a straight line.* I've backed 70-foot narrowboats in the UK--- and these are boats with shallow drafts, absolutely flat bottoms, and no keel or even keel strip to assist in tracking--- for hundreds of yards between rows of boats moored on either side of the canal with only a few feet of clearance to our boat using this technique.* Our boat maintained a steady speed of one or two miles an hour going backwards and tracked a dead straight course.* All it took was judgment of when to give it a brief shot of forward thrust against the rudder to counter the prop walk and keep the boat tracking straight.* The intertia of the boat kept it moving backwards and the brief shots of forward thrust against the rudder kept the stern from walking.

Granted this can become harder if there is a wind to deal with, but in terms of keeping the boat moving steadily backwards while tracking a straight line, intertia and the right timing of the use of forward and rudder is all it takes.


-- Edited by Marin on Tuesday 23rd of August 2011 11:11:33 AM

 

[Vyndance]

My Goodness, I didn't mean to upset anyone. The buzz word was time jleonard. Every cheap cell phone has video capabilities nowadays. Now remember when you mentioned your practice leading to "your" prowess? I offer this challange:

The boat in your avatar, single screw

Single hand, no help at all, no spring lines.

Beam even with ingress side of the slip

Backed in, one dockline around a cleat

Tide and wind condition of your choosing

60 seconds

$100

-- Edited by Vyndance on Tuesday 23rd of August 2011 11:20:31 AM

 

[Marin]

Bob--- If you can find him you owe this guy $100.

 

[Vyndance]

. Oh no I've seen that!

Must be 30,000 lb aft cabin trawler in his avatar.

 

[Marin]

How 'bout if Jay flies the skipper in the docking contest video up to back his boat in? Does that count? Bet it'll back into the slip in a straight line in less than 60 seconds then

 

[Vyndance]

Sure. He does it in the first shot for 100 bucks.

 

[Marin]

No, no, you didn't specify in your initial list of conditions that the boat has to be backed into the slip in under 60 seconds the first time. So Jay (or whoever is driving his boat) should be allowed some practice shots.

 

[Vyndance]

The original challange was to Jay and did not include the fisherman ringer from MD. Therefore if we fly in a ringer outside of the original challange the rules can change. Kind of like someone saying they can hit a Randy Johnson fast ball and bringing Arod to do it for them

 

[LarryW]

I hate to take a mans hard earned*money but I'm damn sure I can do it, no practice shots. It's not rocket science just a little skill is all it takes. Now twin engine boat, I don't know. Larry


-- Edited by LarryW on Tuesday 23rd of August 2011 05:16:36 PM

 

[Marin]

LarryW wrote:
Now twin engine boat, I don't know. Larry

My dog can back our twin engine boat in a straight line.* Assuming counter-rotating props, a twin--- or at least our twin--- will back straight all day long wind and current notwithstanding.* In fact I will often flip our boat around in a marina fairway and back down*between a pair of*long finger docks with little clearance on either side to an open spot partway down rather than go down the slot*bow first. Going backwards the boat steers like a car with differential power (rudders remain centered all the time).

 

[LarryW]

I guess what I mean is I may need a little practice first on the twins. Larry

 

[jleonard]

Well, I never said I could do it in under 60 seconds. It's never a rush thing to get docked.

If it was my old Mainship 34 then maybe as that boat had enough power to do it.

The Albin with the deep keel takes a bit to get the stern to behave....but it does behave. Ther boat does only one thing in reverse...it crabs to port no matter where the rudder is. *So knowing that the rest is relatively easy.

*

 

[healhustler]

My Manatee is a single engine with full keel and barn-door rudder. She washes to Starboard initially, but overcomes this with about 1 knot in reverse. Once I've got the boat to 1 knot, the rudder steers the boat nicely down a fairway. I usually find myself backing in when staying at a marina unless the dock is really noisy.

 

[HopCar]

Only whimps need thrusters or twin engines. Damn I wish I had a thruster or twin engines.

 

[Egregious]

Marin wrote:LarryW wrote:
Now twin engine boat, I don't know. Larry

*

My dog can back our twin engine boat in a straight line.* Assuming counter-rotating props, a twin--- or at least our twin--- will back straight all day long wind and current notwithstanding.* In fact I will often flip our boat around in a marina fairway and back down*between a pair of*long finger docks with little clearance on either side to an open spot partway down rather than go down the slot*bow first. Going backwards the boat steers like a car with differential power (rudders remain centered all the time).

*I wish your dog was on board when I need to back my boat into a 14 foot slip with a 13 foot beam.* I do this each time I take the boat out.

 

[Keith]

My Krogen backs to starboard in reverse. Knowing that, I do the back and fill thing if I have to back in a straight line. Easy to back into my slip, rudder hard to port, turn that way and back in to the slip on my port when approaching. Back and fill, no hurry. It's all in learning the technique, and practice, practice, practice. Thruster helps, but don't count on it!

Matter of fact, when I was a two boat owner, after getting used to the single, it was hard to back the twin back into the slip. Knew how to do it, but lost the technique quickly. It was almost easier to back into the slip by killing one engine!

 

[Moonstruck]

HopCar wrote:
Only whimps need thrusters or twin engines. Damn I wish I had a thruster

*

Gott'em both.

*Gotta a joysticck too, but it has nothing to do with controlling the boat.*

* Oops!* Who said that?*

 

[Budds Outlet]

When I had a single prop and I was in a narrow slip that required I back in off a narrow fairway, I used the burst and glide process with the wind and current taken into consideration. The Admiral would chant in my ear "if you think you're going slow, go slower."

 

[Marin]

Egregious wrote:
*I wish your dog was on board when I need to back my boat into a 14 foot slip with a 13 foot beam.* I do this each time I take the boat out.

I'll be happy to hire him out to you.* His rate is $25/hr but of course you'd have to pay his airfare and lodging expenses, too,*since you're on the east coast.* Probably be cheaper to just buy some extra fenders


-- Edited by Marin on Tuesday 23rd of August 2011 09:50:40 PM

 

[markpierce]

Don't forget meals and some bar drinks.

 

[FF]

Many commercial boats will have deeper reduction gears , and larger diameter more efficient props .

The size of the prop is such that the side view of the blade area shows it almost as big as the rudder it self.

Even with a good head of steam in reverse the rudder is small for the job.

Learning to steer with the prop, rather than the rudder is the solution.

A good hand with a spring line is also a big help.

Yacht experience is not a help on these boats.

 

[jleonard]

"I wish your dog was on board when I need to back my boat into a 14 foot slip with a 13 foot beam."

When I had my Mainship (for 14 years)*my slip was 4 inches wider than the beam.* As FF* said, the rudder stayed in one dorection and the rest was accomplished with*gear and throttle. I never used a spring line to get into my slip, however on many occasions**it took more than one try. It was a matter of how many slips ahead of mine I made my turn...was it a two slip wind or a three slip wind?

And of course there's the golden rule....if it doesn't feel right go back out and make another approach with the necessary corrections. Don't try ot "force it".