The Couple Across the Dock from Me Invented Something Pretty Cool ...

[Charlie]

Originally Posted by David M

Clever idea, but all he has to do is to slow down and he would not need it.

I have a hard time judging the speed on my boat. Also when I am at idle my boat goes too fast to dock. I have to slip it in and out of gear. Something like this would be very helpful though I think I would make it rather then buy it.

[Therapy]

Originally Posted by Seaduction

DANG!! Too late again!

Yea,

I just hate it when I find out I am just not smart enough.

[S/V Alchemy]

Originally Posted by denverd0n

Interesting idea, and kudos to them for being able to make and market this product.

Still, I have to agree with the person who said they wouldn't need it if they weren't coming into the dock way too fast (at least in that video).

Well, there's no cure for stupid...

On a more constructive note, one of the reasons people cite for coming in "too hot" (you can hear the roar of full throttle reverse some distance, I've found) is that nice and slow means a sluggish helm, leading to difficulties of a different type, like having to bounce off your neighbour. If I get a shortish line on a cleat, I am less likely to need helm or speed to finish up.

Me, I learned my chosen docking method involved lots of practice in cross-winds close to buoys. I tend to put my engine in neutral and bleed speed via sharp turns. If I have a cross-wind blowing me off, I aim for the dock end and "crab" in. As long as the midship cleat is reasonably close to the dock end, I can lay a line onto the right bollard and step off with a hook and a second line.

I rarely even use reverse. At departure, unless I've got big wind to deal with, I push off the dock and helm over until I'm pointing out and then shift to forward. With big wind, I will warp off in reverse. This isn't meant to be boasting or overly clever, but it does reflect the course of practice I undertook when I had to unexpectedly sail into my dock. Ironically, since I rebuilt my engine, it's very reliable and I could power in and reverse like most people, but I like the challenge and the relative quiet and lack of drama of docking in neutral.

Even so, I can see a use for this gadget in some boats and with a number of otherwise decent sailors who just get nervous docking. It's handy for "stop and drop", too.

[sarafina]

I'm all over this. We usually have big winds to pull across when docking and they make docking slooowly difficult to say the least...

This is sweet.

On days with no wind, cool, I can gauge it until I drift into the dock and hop off with a line.

But on those windy days? This and reverse would be a cherry combo.

[cal40john]

I've seen something similar for the last several years at the boat show, a throwable hook.

This guy made his own about 2/3rds of the way down the page:
Deck Modifications

[Celestialsailor]

It looks like an accident waiting to happen. Miss once at the speed he is coming in and there is going to be some damage.

[SabreKai]

You know, it might be that he came in hot just to show how easy the gizmo works even if you are moving at a fair clip.

[Celestialsailor]

Perhaps...but I think it would be something that might build a false sense of confidence.

[hellosailor]

So instead of throwing a line and snubbing it up, he's using a ball as a toggle to catch under the cleat.

Just seems like one more way to complicate life, I don't know what's so hard about throwing a line, even one-handed.

Except up in BC. I've never been able to get an answer, why they don't use cleats but have low "railings" on all the docks. Wood's cheap, metal castings are taxed too high to import?

[Nicholson58]

Originally Posted by senormechanico

Axle shafts transmit torque to the wheels.
The suspension takes all the sideways forces such as cornering etc.
The axle shafts have splines to absorb suspension movements.

On a boat, the torque from the engine is transmitted to the prop.
The prop's thrust is transmitted back up the shaft and in most installations, is actually PUSHING the engine and transmission forward which drags the boat along with it via the engine mounts.

NICE INSTALLATION - ALCHEMY

The auto suspension guides motion of the wheel; the axle half-shafts follow the motion. There is a spline at the wheel hub and another at the differential where the inboard end of the half-shaft is inserted. Splined ends are firmly fixed and do not slide in operation. Generaly a circlip on the spline engages a groove inside the differential output stub shaft. The outboard end of the half-shaft has a universal joint. The inboard end has a CV joint. The CV and universal transmit the torque and permit the wild contortions the shaft must make to follow the suspension. The universal only allows bending about its two crossed axis. The CV allows bending about the two transverse axis as well but also allows translation so that the shaft can extend and contract lengthwise. In an auto, these motions are extreme. In a boat, the same motions are minor.

The aquadrive has all of these elements in a more compact package since the motion required is tiny. Note the Aquadrive has the thrust bearing to seperate this force from the power train. The bearing takes the thrust load exerted by the prop. Between the bearing and the transmission is a short floating shaft. One end is like the universal and the other end is like the CV joint. This is a really great solution for a boat & prop set-up.

Only in small engine & transmission systems is the thrust transferred directly to the transmission. It should be taken up by a thrust bearing in all larger systems. Otherwise, the crank bearings, engine mounts etc are subject to loads the engine makers usually don't account for well.

Our drive line is Westerbeke 6-cyl to a twin disk 2:1 reversing transmision. There is a large Aquadrive between the twin disk (blue) and the Hundested hydrostatic pitch control (red). The Hundested incorporates the trust bearing internally. Output from the Hundested is a 2 inch shaft to the 24 inch 3-blade. Pitch control is a rod internally through the prop shaft to operate the blade pitch. I don't know why this pitch control system is not more widely known. It is a fantastic tool for matching the engine to the conditions. Hundested Propeller A/S: Home

[S/V Alchemy]

Originally Posted by Nicholson58

NICE INSTALLATION - ALCHEMY

The auto suspension guides motion of the wheel; the axle half-shafts follow the motion. There is a spline at the wheel hub and another at the differential where the inboard end of the half-shaft is inserted. Splined ends are firmly fixed and do not slide in operation. Generaly a circlip on the spline engages a groove inside the differential output stub shaft. The outboard end of the half-shaft has a universal joint. The inboard end has a CV joint. The CV and universal transmit the torque and permit the wild contortions the shaft must make to follow the suspension. The universal only allows bending about its two crossed axis. The CV allows bending about the two transverse axis as well but also allows translation so that the shaft can extend and contract lengthwise. In an auto, these motions are extreme. In a boat, the same motions are minor.

The aquadrive has all of these elements in a more compact package since the motion required is tiny. Note the Aquadrive has the thrust bearing to seperate this force from the power train. The bearing takes the thrust load exerted by the prop. Between the bearing and the transmission is a short floating shaft. One end is like the universal and the other end is like the CV joint. This is a really great solution for a boat & prop set-up.

Only in small engine & transmission systems is the thrust transferred directly to the transmission. It should be taken up by a thrust bearing in all larger systems. Otherwise, the crank bearings, engine mounts etc are subject to loads the engine makers usually don't account for well.

Our drive line is Westerbeke 6-cyl to a twin disk 2:1 reversing transmision. There is a large Aquadrive between the twin disk (blue) and the Hundested hydrostatic pitch control (red). The Hundested incorporates the trust bearing internally. Output from the Hundested is a 2 inch shaft to the 24 inch 3-blade. Pitch control is a rod internally through the prop shaft to operate the blade pitch. I don't know why this pitch control system is not more widely known. It is a fantastic tool for matching the engine to the conditions. Hundested Propeller A/S: Home

It's actually a friend's installation, but I will closely mirror it on my boat. That was one of the shots I need to show the welder and the fabricator.

His is an 18-tonne Goderich 40 ketch driven by a new Volvo 55 diesel to the Aquadrive via a 1.25" shaft to a 18 x 15 three-blade Autoprop. Mine is a 16 tonne custom steel 41 foot pilothouse cutter driven by a new Beta 60 to an Aquadrive via a 1.24" shaft to a 19 x 15 four-blade Variprop.

The soft engine mounts plus the Aquadrive mean you can be standing directly over the engine and barely feel it. The shifting, isolated somewhat from the engine, is smooth and responsive and the "bite" to either stop the boat or reverse is significant and a big help in manoeuvering these steel beasts in close quarters. Lastly, bad alignment issues are in the past, although one should ensure a decent initial alignment, even with a CV joint.

I think these joints are great in making a quieter motoring experience possible, and in reducing wear on the drive train and crankshaft. As I was re-engining anyway for long service, I decided to do it the right way.

That is indeed a sweet piece of engineering to alter the pitch underway, but the Variprop is easy to adjust in the water, and I can set "sweet spots" for cruising forward and for loads of stopping power in reverse.

[Andrew Troup]

I wouldn't say pretty cool idea.

I'd say very cool idea.

[leftbrainstuff]

Originally Posted by avb3

Am I missing something?

The only thing the shaft can produce is torque, a rotational force. Only the propeller can produce thrust. As such, I don't understand your last sentence.

CV joints are only designed to transmit torque. As the prop exerts an axial reaction to the propshaft you need to ensure the CV joint isn't carrying this load.

[S/V Alchemy]

My clever dock neighbour has refined his design and now has something called "The Docking Stick".

Docking Stick Docking Tool.wmv - YouTube

Due to size, simplicity, the height of the freeboard on my steel boat and the sheer number of boat hooks I tend to have clipped onto shrouds and handrails, I think I would prefer this to the Dock Wand.

[carstenb]

Well, I like the second one better than the first one. The rubber ball one would not be something I would trust. What if the ball came off - good bye bow