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Thanks for your comments, folks. It's really very compelling reading. I'm back in the aviation /aerospace sector and reading this again brings back memories. R.A. Structural Analysis Engineer Excelnet

There's this 'black metal' method which you use a program to make the entire laminate have isolinear properties. Then all you have to do is analyse it using finite element method as if it was a metal with uniform characteristics.

Personally, I don't really find a need to use stern thrusters when the boat is moving at a reasonably high speed. That is because one is usually not within reach of obstacles when high speed is engaged. That means the maneuverability is less critical at this point (unless you're doing a stunt...

I can see big ships yelling "TUG assistance" but not yachts.

Thanks for your response, guys. However, I'd like to have very solid proof before I even consider going to higher authority. As a structural/material engineer, I know that it is impossible to rate a certain fitting, due to the lack of knowledge of the process that goes on like extrusion...

Is it advisable to use brass fittings/connectors/adaptors for a marginally high pressured hydraulic system such as an autopilot which can go up to 1000psi? I am convinced that it is a wrong move, but have been overruled by higher authority due to cost issues - brass is cheap, while stainless...

Yes, it helped somewhat. Thanks.

Relocating batteries is easier said than done. There needs to be sufficient ventilation, especially for wet cells which have sulphuric acid as the electrolyte. I'd have to install another moisture eliminator/demister/blower there to avoid any untoward incidents. Not to mention I have my fresh...

I certainly agree that the same amount of thrust applied at the extreme outboard location would generate a much larger torque.

Batteries are in the engine room. Engine room is aft/middle of the boat. We're talking about distances of 40ft one way when you consider the wiring. Loads about 680A. I've been advised against parallel switching. I'm wondering if it's possible to stagger or sequence the starting, so it doesn't...

Twin engines, actually. Each have their own primary 8D batteries but it looks like I will have to siphon off some for the other equipment on board. I do have a sizeable generator and efficient battery charger though and it will most probably keep the batteries charged and in good shape. Then...

Hi, I build yachts and in this industry there tends to be lots of additional demands on equipment with reduction in power supply. I'm using limited 8D and 4D AGM batteries for engine, house and generator but I can't figure out how to keep the bow thruster, anchor windlass and down to something...

If both the bow and stern thrusters were installed, would the bow thruster be more powerful or the stern thruster? Or does it depend on the function of the vessel? How much more powerful anyway? The stern is usually heavier for the common bow-up position. I figure it requires more power...

When you mention electrical circuitry does it need to be as complicated as PLC?

Well, it seems to unanimous then. No one has exactly seen any vessel with only stern thrusters installed. I think stern thrusters and rudders seem to be somewhat interchangeable judging from what ktm5 says. Any other comments? Cheers!

I thought as much. Thanks guys, for your input. I appreciate it!

That means the rudder is not enough to maneuver the boat. Stern thrusters still need to be utilized. When you say stop the ship, I assume you mean neutralize the throttle and use only bow/stern thrusters? So have there been instances where only stern thrusters are used without the bow thrusters...

Yes djw2k3, you're right when you say that it is usually used for mooring operations. Especially at unprotected areas, bow thrusters can be a desperate necessity for maneuvering to get in and out as both the wind and waves/current can make it difficult. It's used mostly in yachts. Tankers and...

I have personally found that more boats use bow thrusters rather than stern thrusters, for the simple reason that the keel and rudder are located towards the back of the boat, thus making the stern thruster "unnecessary". However, by observation, the back portion of the boat is...

Is it possible to connect both the refrigeration and air-conditioning to one sea-water pump? The flow rate is marginally enough to handle both systems, but physically, there doesn't seem to be a way to adapt the system. The boat in question is relatively small with limited air-conditioning and...