adding bowthruster to 60 foot ferrocement boat

[ted manos]

I have a Samson 60 ferrocement boat and am desiring to add through hull bowthrusters to it. Have talked to people at Imtra who blew me off. Issue is how to best make the transition between the ferrocement and the metal pipe that holds the thruster....Any suggestions on approach or unit?

[Sailmonkey]

Originally Posted by ted manos

I have a Samson 60 ferrocement boat and am desiring to add through hull bowthrusters to it. Have talked to people at Imtra who blew me off. Issue is how to best make the transition between the ferrocement and the metal pipe that holds the thruster....Any suggestions on approach or unit?

Why use metal? I am no ferrocement expert (far from it) but I would think it would be much easier to bond with epoxy a fiberglass tube in place.

Unless there is a whole host of other problems with cement and epoxy.

[ted manos]

Thanks for comment
one would think that fiberglass would be the way but apparently there are differential curing rates involved with the cement and the glass and issues with the glass sticking to the cement.....this is just rumor.
I cant find anyone who has any experience and the "experts" who sell the units blew me off so not sure which way to go or do this before I bore a huge hole in the side of the boat.

[Sailmonkey]

How about these guys?

http://www.epoxyproducts.com/ferroltr.html

I know they're talking paints, but they're talking ferrocement. They may be able to help steer in a direction.

[Steadman Uhlich]

My initial thought was for an external thruster. The IMTRA.

But as shown below, it is recommended for smaller vessels.

A big heavy FC hull may be too much for these.

You wrote that IMTRA did not respond well to you? Please be more specific about their response. What did they say, specifically?

https://www.westmarine.com/buy/imtra...JXpxoCGMbw_wcB

IMTRA
The externally mounted pod-based EX-Series is a practical thruster solution for displacement and semi-planning boats between 6 and 18m length, independently of hull form, hull material, propulsion and depth. These pod thrusters are an excellent choice where a tunnel thruster cannot be fitted or as an extremely compact stern thruster. The EX thrusters can be used in all types of vessels such as: sailing boats, catamarans, motorboats and houseboats made out of steel, aluminum, wood or GRP. The flexible mounting at the extreme bow of the boat hull allows a deeper position underwater which creates an optimal leverage compared to conventional thrusters. EX thrusters can, therefore, move larger boats by using nominally less power than conventional thrusters. The EX-Series Bow thruster can be installed in most boats between 20 and 45'. These pod thrusters are an excellent choice where a tunnel thruster cannot fit or as an extremely compact stern thruster. They are also especially good for retrofitting. The flexible mounting at the extreme bow of the boat hull allows a deeper position underwater which creates an optimal leverage compared to conventional thrusters.
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[Steadman Uhlich]

Ted,
Whatever solution you find, I hope you will return to CF to post some photos showing the solution, with a description of the mod and costs and results in handling the boat.

[agb512]

talk to Keypower, Kobalt manufacturing. Go hydraulic

[ted manos]

Originally Posted by Steady Hand

My initial thought was for an external thruster. The IMTRA.

But as shown below, it is recommended for smaller vessels.

A big heavy FC hull may be too much for these.

You wrote that IMTRA did not respond well to you? Please be more specific about their response. What did they say, specifically?

https://www.westmarine.com/buy/imtra...JXpxoCGMbw_wcB

IMTRA
The externally mounted pod-based EX-Series is a practical thruster solution for displacement and semi-planning boats between 6 and 18m length, independently of hull form, hull material, propulsion and depth. These pod thrusters are an excellent choice where a tunnel thruster cannot be fitted or as an extremely compact stern thruster. The EX thrusters can be used in all types of vessels such as: sailing boats, catamarans, motorboats and houseboats made out of steel, aluminum, wood or GRP. The flexible mounting at the extreme bow of the boat hull allows a deeper position underwater which creates an optimal leverage compared to conventional thrusters. EX thrusters can, therefore, move larger boats by using nominally less power than conventional thrusters. The EX-Series Bow thruster can be installed in most boats between 20 and 45'. These pod thrusters are an excellent choice where a tunnel thruster cannot fit or as an extremely compact stern thruster. They are also especially good for retrofitting. The flexible mounting at the extreme bow of the boat hull allows a deeper position underwater which creates an optimal leverage compared to conventional thrusters.
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they claimed to have no experience with Ferro cement installations.
Problem is that I don't want to take a 60 foot 25 ton boat into a marina with a single screw motor so I need a creative cost effective solution.
The external mount would be a nice option....would hate to affect hull integrity for this project.

thanks for your advice.

[SV Bacchus]

Originally Posted by ted manos

Problem is that I don't want to take a 60 foot 25 ton boat into a marina with a single screw motor so I need a creative cost effective solution.

The external mount would be a nice option....would hate to affect hull integrity for this project.

I am no expert on FC hulls, that is for sure. Are they not crisscrossed with much steel (rebar)? I would think any hole not made during the build would possibly affect the integrity, no?

Maybe the best long-term solution, and probably cheaper, would be to hire a captain for a couple of days and build your confidence in handling with the single screw.

[TrentePieds]

Quote: "they claimed to have no experience with Ferro cement installations."

That can hardly be characterized as "blowing you off". That seems to me to be an absolutely factual, and therefore legally unassailable statement, and one that any competent businessman would make in the circumstances, since the matter speaks to liability issues. The reply is only common sense in light of the American legal system, and the general litigiousness of American society, being what they are.

I was around - just around the corner, literally - when these FC boats were being built by Samson Marine of Richmond B.C. Some were good, some were excruciatingly bad, a fundamental problem being that the "plastering" of the "armature" has to be done in one continuous, contiguous operation so that each application of fresh, not-yet-cured aggregate reacts chemically with, and bonds with, fresh, not-yet- cured, aggregate. Nothing will bond satisfactorily to 50 year old, long since cured, aggregate. Thus cutting for a tunnel is, I will wager, a sure-fire way to ensure that the boat will sink not too long after the installation of the tunnel.

If you are interested in the ins and outs of FC boat building, I recommend that you find the little book by Jay Benford that addresses the matter in a most admirable way.

Men who earn their living on these shores handle 40 ton single screw ships as a matter of course. Such are the vessels they earn their living in. Bringing such a vessel alongside is perhaps a little frightening the first time you try it, by try it you must, and becoming competent at it is an absolute requirements for any man who would own such a ship. As someone else said: Pay for the services of a competent man to teach you how. Among the things he will tell you is that you give a pass to any mooring that is too small for your vessel - which in your case would deny you the use of finger slips in yachtsmen's marinas. Experience will teach you what is adequate and what is too small.


Here is a video of a man who knows his stuff. Single screw ship, bigger and heavier than yours. In very confined quarters. No thruster either - just competent handling:

www.youtube.com/watch?v=jBOJ779LtBM

All the best

TrentePieds

[Davidhoy]

Originally Posted by TrentePieds

Here is a video of a man who knows his stuff. Single screw ship, bigger and heavier than yours. In very confined quarters. No thruster either - just competent handling:

That's some impressive boat handling! Notice how he barely uses the wheel, until near the end of the video. Check out a technique called "back and fill" as a way to maneuver a boat in tight spaces. It relies upon prop wash and prop walk to turn a boat in not much more than it's own length. You leave the rudder hard over (to port or starboard, it depends on which way your prop rotates), and then use short bursts of power ahead and astern to swing the boat around. Learning this technique improved my confidence dramatically. Sure there's more to close-quarters maneuvering than this one skill, but it's a very good start.

BTW, I have a bow thruster on my 46ft full keel Morgan, but I rarely use it.

Regards,
David

[Steadman Uhlich]

Originally Posted by ted manos

I have a Samson 60 ferrocement boat and am desiring to add through hull bowthrusters to it. Have talked to people at Imtra who blew me off. Issue is how to best make the transition between the ferrocement and the metal pipe that holds the thruster....Any suggestions on approach or unit?

Ted,
What model of boat? Sea Lord?

Please post a photo(s) of the boat.
Any photos of the boat on the hard or slings, showing the hull form.

What is the displacement of the boat?

Did you build the hull? Was it done by a yard or by an individual?

Where are you located? There are some services who focus on installing thrusters in boats (I saw mention of one in Florida) and they travel to boats to make the installs. They may have done a FC hull before.

[TrentePieds]

"Backing and filling" is actually a term that goes back to square-rigger days and denotes a technique for bringing a ship downriver against an adverse wind. It was as tricky as it was elegant, and it took a brave skipper and a competent crew to execute it.

"Backing" refers to a sail taking the wind "aback" (i.e. on the fore-side of a square sail) and "filling" refers to filling the sail with wind again. In brief, the maneuver entailed this: with an onshore, up-stream wind blowing, you laid the ship athwart the river so the onshore wind was on the beam, which of course meant that she had the flow of the river on the other beam. She would be carried down-river by the current, and she would be held in midstream, and off the banks, by "filling" the main course and the main topsl(s) to make headway towards one shore, and "backing" those same sails to make sternway towards the other shore. Pivoting the vessel around a point roughly midships so she always lay beam to wind was done by deft manipulation of headsls and spanker.

But rivers meander. In consequence there were time when the ship could be permitted to make headway downstream and other times when she had to be compelled to make sternway until she came to the next meander.

As you may imagine this would keep the crew hopping, and getting your timing wrong could easily result in -uhm -"awkwardness" :-)

I have been lectured on how to do it, but regrettably [or maybe not :-)!] I've never had the experience.

I supply the above only as an interesting historical curiosum. I have no problem with us Sunday-sailors using "backing and filling" to refer to maneuvering under power. In fact, I have always demonstrated to students how you turn a vessel around her "pivot point". In many ways I think it is easier to do that in a full-keeled vessel of some displacement (and therefore inertia) than it is in a five ton fin-keeler like TrentePieds. TP is really too "windy" to do it elegantly in any kinda blow. I think that the sundry "sailing schools" should make a demonstrated ability to turn a cruising vessel 360º on her pivot point a prerequisite for issuing any kind of certificate of competence :-)

TP

[JOHNMARDALL]

I recommend a fiberglass tube for your ferro-cement hull and also recommend an end connection method that does not require fiberglass to adhere to the concrete. If you'd like to send me a personal note, I'll give you my email address and send sketches, a step-by-step process, and a thruster recommendation. Getting the tube in the right place is the most important issue - if it's too shallow or too short, the thruster will not perform properly no matter what else you do. A very heavy 60 footer is getting to the limits of an electric thruster, so I'll also provide some information on a hydraulic unit.

Best Regards

John Mardall
Vetus Maxwell Group

[Davidhoy]

Originally Posted by TrentePieds

I supply the above only as an interesting historical curiosum. I have no problem with us Sunday-sailors using "backing and filling" to refer to maneuvering under power.

Thanks! I always wondered where the term came from, but never took the time to look it up. Makes a lot of sense now, since most nautical terms harken back to years past. It's amazing how few people know how to do this, as it's very simple once you wrap your mind around it. I've had people comment on my boat handling over the VHF when they see me spin my boat around on the New River while waiting for a bridge to open. But in reality, I feel like a novice, especially when I see guys like in that video...

I do, however, like the peace of mind of having a bow thruster available, should I ever need it.

Regards,
David.