Bow thruster installation procedure

I have a bowthruster, fiberglass tube and all the necessary bits to install next haulout. I plan to lay-out the holes myself, then have our local yard in St. Lucia do the cutting, glassing and faring. I want to know as much as possible about the work they will be doing. Keith's excellent photos are my starting point.

Obviously the integrity of the joints between the tube and the hull are critical. The tube goes well down in the vee of the hull and access underneath is very limited. What is the correct method of making this inside joint? Other pointers appreciated.

Mike

Mike* --* On my DeFever, the yard that did the bow thruster*install last year charged me for about two days of FRP work. Lots of mat and resin was used to tie the 8" tube and hull together. Equally big hours went into moving the holding tank back about 2 feet and redoing the forward sole to gain access. It was quite a chore.

The manufacturer of you thruster should provide very specific instructions on how to install the unit. Ours came with a complete manual, about 50 pages.* If you don't already have one, you might want to get one ASAP. There is no room for error or guesswork here. ...........Arctic Traveller

Dismantling the joinery in the forward cabin and rebuilding it afterwards is my job. Fortunately there are no tanks or services to be moved. The yard will only be cutting the holes and glassing in the tube.

The manual gives clear instructions on the mechanical and electrical installation, but nothing useful on how the tube itself is fiberglassed/epoxied into the hull from the inside where access to the underside is very limited.


-- Edited by Shoalwaters on Sunday 16th of January 2011 10:49:37 AM

And I just deleted the thread about this for spamming purposes.....

Baker wrote:

And I just deleted the thread about this for spamming purposes.....

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Baker: I thought you might - rightly too, that's why I started a new topic. Several of the*companies that instal bowthrusters have*websites showing*their installation procedures. Unfortunately none of them give details of how the underside of the pipe is glassed/epoxied in when the access is very limited.

Thanks Mike, that's got me pointed in the right direction.

Mike

No where near as hard as glassing overhead after replacing deck core from the inside.


No big deal, just the proper tools ( metal fence painting depth roller), steel roller and peal ply if it will take a long time .

More info please Fred

After participating in and furthering the spamly post I am getting punished. Now my bow thruster is acting up. I'm going to post in the mechanical forum.

Old Stone wrote:

Had to add the picture below. Can't remember where it came from. Hope it was not from on earlier posting from this forum, that would be embarrassing.

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I think that's Rick B's pic. If so, and if it's his copyright, you may owe him his choice of boats a la Marin's Fleming.

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dwhatty wrote:I think that's Rick B's pic. If so, and if it's his copyright, you may owe him his choice of boats a la Marin's Fleming.

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*Yeah, that is mine. I don't need another boat but I could use some help raising the one in the picture.*

Personally, I would*be doubly careful when buying a boat that had an amateur bow thruster install. A*detailed description of the install including electrics should be made and kept. It is a major thru hull that cannot fail during a heavy sea when hull forces are at their greatest.

Mike wrote:How can you tell if one installation is professional and the other amateur?

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One installation is owned by a guy who used to have a lot more money.



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sunchaser wrote:It is a major thru hull that cannot fail during a heavy sea when hull forces are at their greatest.

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What is the failure that you worry about?

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Mike

The giveaways on a poor job can include:
-Wrong elevation,
-Wrong diameter and power
-Not plumb or misaligned
-Improper bonding and*cathodic protection
-Improper electrical wire, fuse and switch sizing
-Kicks out after minimal use
-Water leaks
-Poor fairing inside and out
-Insufficient mat used or only "glued"
-Wrong resins/incompatibility with hull layup
-Poor layup
-If a cored hull, the "proper" resin infusion into the coring must be demonstrated

I've had considerable industrial experience and involvement designing and building some of the largest FRP tanks and settlers used. The toughest job is replumbing after an install such as you'd fine when new through the wall piping is required. But I would*not cast a final vote on a thruster job being good or bad without a good surveyor or installer*who has the requisite experience to know what he is looking at.

For all the reasons listed above, and the cost involved, and the fact I would hardly ever use it, is why that particularly important part of my boat's anatomy is going to stay pristine......

Peter B wrote:

For all the reasons listed above, and the cost involved, and the fact I would hardly ever use it, is why that particularly important part of my boat's anatomy is going to stay pristine......

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Good choice Peter. I have one, but it doesn't pay it's way. Don't really need it.

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I prefer boats with a watertight compartment in the bow , as required on commercial boats.

Knocking a 10 inch hole for 30-50 seconds of push (before the overheat) doesn't ring my bell.

Don't get me wrong, I am a supporter of thrusters. I have active stabilizers and PSIs too. I enjoy all three and the benefits they bring. My salient point remains, do it right with big through hulls - and all three can and have been*done right thousands of times . All done right add to resale ease at some point too. Done*wrong ---- the consequneces are obvious.