Converting our workboat to tugboat.

Thank you very much for all this information. So really the first step ( and easiest) as a trial would be to find a 24" by 13.5 inch 4 blade. See how that works. The reality is that no-one would run this engine at 2800 rpm unless it was an emergency I would think. That is really screaming for one of those.

I have located a company that makes steerable nozzels and am discussing what is involved in have one of these made.

And yes I agree I am trying to keep everything as simple and manual as possible.

 

That's another story; the basic dimensioning point is still the max power case (200 hp @ 2800 rpm). You might use a 14" pitch, your engine will be operating fine with better fuel economy with that. The supplier of the nozzle should have some calculation insight regarding the nozzle profile they use.

 

Hello All,

Ok well I spent some time trying to track down the propeller. Very difficult to find. Looks like I will have to get one made. Approx $ 1400.00 I assume this is the going rate.

Also while working in the engine bay I discovered that the bilge pump was broken. Can any one suggest a very good 1000 gph pump that can handle the oil and such found in the bilge? I looked at the mainstream ones and they all seem to be a lot of plastic?

I have attached some more picutres of the steering to work towards the second station ( fly bridge) I wasn't able to find any part numbes or serial numbers on it.

I am going to review the link now to see if I can identify visually.

Thank again for everything.

 

the best I can see is Morse rack single cable?

http://www.jamestowndistributors.com/userportal/document.do?docId=691

 

If your steering system works for the rudder you have, I wouldn't change it. Old time wisdom,"If it ain't broke, don't fix it."
My concern is you won't have enough rudder power with just the boats rudder, to handle the barge.

You can experiment by trial and error trying to modify it. Could be expensive.

You can set up a 12volt electric drill motor and a belt drive on lower helm. Install a 3 position switch on flying bridge as a NFU joy stick. Left/stop/right. NFU = "non follow up", means the rudder stays where you put it until you run the motor the opposite direction to center it. I like these.
The other kind of joystick is a follow up joystick, the rudder follows the stick and is at the same angle the joystick is. I don't like those. If someone bumps it, you are hard over rudder.


A switch something like this but spring loaded returns to off if you remove your hand

 

Here is a photo of a belt drive auto pilot for a sailboat helm, if it gives you an idea.

 

Thanks Baeckmo for those figures - I did a rough and ready calc earlier on the force generated by a 2.5 inch hydraulic steering cylinder and got over 4000 pounds which I'm sure to some SEEMS like a silly number - But it could be converted to 1800 Kg or approximated to 18,000 Newtons, so I chuckled a bit when I saw you'd come up with 18kNewtons for your Thrust calculation.

Obviously there are so many other factors like leverage to consider but this little coincidence is a lesson not to underestimate the magnitudes of Hydrodynamic forces - that wire steering is going to last as long as a 25 cent Guitar String (and sound about the same when it goes) Whoaha I Got de can't steer ma tugboat blues - De Daa de de dum.

I agree on the thicker ID pipes and would also add that though these systems ARE hydraulic, that doesn't mean any hydraulic fluid will work - the viscosity on some of these systems specified for colder temps is closer to kerosene than hydraulic oil and using too thick a fluid can actually lock up the helm units.

 

YoBarnacle - I don't think that is a very fair way to quote me - reading back through the previous posts in the thread, including your own, the context has never been about restoring a recreational boat and returning it to factory condition. Baeckmo's post which I quoted was about upgrading using a nozzle for increased thrust.

Big Builder set the criteria that it is going to be upgraded to dual helm positions and in that context series or parallel push pull cable steering is not really sensible for a commercial vessel, particularly when almost every post is about upgrading and increasing available thrust and or rudder area, and you have been a strong advocate for going that latter route! Hydraulic is the platform which will allow that development.

As for "Unless its wornout or corroded or damaged..." - any cable which has been on a saltwater boat for a couple of years will be exibiting one or more of those properties - though maybe not as an immediately visible symptom.

Consider failure modes of push-pull vs. hydraulic - instant and catastrophic vs. slow and progressive (and normally easy to fix as a Get-U-Home by topping up fluid). Then consider that the vessel is proposed being worked on a daily basis while the waters are thawed - 8 months of the year?
What is the potential cost of lost business, lost reputation and downtime resulting from a broken cable and I think it is hard to justify retaining the current system.

I have come across many Hydraulic sytems over a decade old still on their original cylinders and helm units but precious few push-pull with the same longevity - they almost have a 'disposable' quality - built in obselescence for the recreational market?

Now, dual cable... simple and classic, a very different story but even those would be hard to justify retaining for a modern day commercial venture.

Even if the current system seems to be in miraculously good order, wipe it down and slap it on Craigs list (or the Canadian version thereof).

 

I also recommended hydraulic steering. the quote was exactly your post. sorry if you were offended. I think "last as long as a 25 cent Guitar String" is melodramatic and incorrect. That's my opinion.
Big Builder is looking for an add on to the current system for the upper steering station.
Since I sailed commercial vessels for 43 years, and by law, was not only master of vessel, but an "agent" of the company, I know a little about business economics.
An AGENT is required BY LAW to save the company from financial harm, if it's in his power to do so.
Expenditures for equipment come directly out of profits.
Since I don't know him personally, I can only surmise Big Builder wants to do this conversion in the most cost conscious way consistant with safety.
The hydrodynamics on the rudder are determined by blade area and volume and velocity of water flow. You can have a small fast column of water or a large slow column of water, but no mater what tricks you try, you can't get more power out than goes in. All you can do is maximize efficiency for the specific use you intend. A nozzle will help do this. A larger but less pitch prop will help. The pressure on the rudder from the prop won't change more than a few percent. Ergo the hydrodynamics are not appreciably changing.
All our comments are intended to help. Yours as well as mine. Everybody has opinions. Big Builder gets to decide which help suits his particular needs best.

Among my licenses, I'm also a 1st Class Pilot Any Gross Tons, for entire Great Lakes system. I assure you Ontario is not on salt water.

 

Don't buy new prop until you have seen what the (future) nozzle will need. Nozzles allow the use of slightly higher pitch, depending on nozzle shape.

 

https://www.boats-and-harbors.com/classifieds/

the online issue here:
http://www.pagegangster.com/p/xuhOw/

Every commercial operation I know of gets this 'Boats and Harbors"
If you already are, ignore this post.
Classifieds for new and USED equipment and parts.

 

Good advice.
Nozzles and props are often sold together as paired units. The clearance between the blade tip and inner nozzle surface is very tight, to keep line (rope) from getting trapped in between. With an 11 foot prop, you couldn't insert a finger between nozzle and blade tip.
Nozzles are called "line suckers" by tugmen

 

Hello All,

Well I am back at it for a little bit. Had to get a barge section I was building out of the shop so I could get this boat in there.

I couldn't find the prop that I needed ( 8 week wait right now) so I picked up a 24 by 18. The did a bushing for me to take it down to the right shaft size.

I know its not what the vessel needs but it is a lot better than a 24 pitch.

my questions is:

- can some one give me directions on best way to remove the old prop? Not sure it it will just come off or not.

- Also the machine shop gave me stern warnings about new prop installation. The indicated lapping might be necessary. They have provided a bronze bushing and stepped key to install. Any advice on proper installation will be appreciated.

Thank you

 

watched many props being pulled and pulled a few myself.

a prop puller tool resembles a big gear puller. Hooks over prop blades and a sturdy center bolt screws against end of prop shaft and provides tension.

a little heating and beating on prop hub combined with tension of puller, encourages it to pop loose.



All the props I installed slid on over keyed shaft and tightened up with two prop nuts. The keeper nut got wired with a twist of stainless wire.

Some of these props were held by a crane as we wrestled them on. Yours can be picked up by hand.