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Saturday, July 16th 2011, 7:31pm

Iowa Class Battleship Design as Basis for Ocean Liners

I have been interested in the Iowa class battleships for a long time. They are the fastest and most poweful warships ever put to sea by the United States. They packed a powerful puch with their nine 16" guns and numerous smaller caliber weapons.

The reason i started this post was to ask the question: "Is is possible to use the Iowa class hull form and machinery and convert it into a state-of-the-art ocean liner?"

I started this on Springsharp but haven't got really far.

The main reason i think this would be feasible is because the necessary calculations for speed and power as well as machinery sizing and placement is already done and makes the job easier, in my opinion.

The only thing i see is increasing the freeboardfor better seaworthiness (i think i read somewhere that the Iowa's had trouble in this department) and building an entirely new superstructure and spaces for passengers. Removing the barbettes, armor, all armament (as this will be a commercial ship after conversion), willall help to significantly reduce displacement (and hence draft). This weight i took off from armament and other warship essentials can now be channeled into stronger turbines giving a higher top speed (perhaps 36-37 knots)

If you guys have any other ideas, feel free to comment and give suggestions and advice ot help me undertake this bold design.

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Saturday, July 16th 2011, 8:16pm

That sounds like a total rebuild, except for the hull itsself. I suspect it might be cheaper just to build a new liner...

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Sunday, July 17th 2011, 7:13am

RE: Iowa Class Battleship Design as Basis for Ocean Liners

Quoted

Originally posted by RMSCANADA
The reason i started this post was to ask the question: "Is is possible to use the Iowa class hull form and machinery and convert it into a state-of-the-art ocean liner?"

Answer: yes, but it would not be in any sense of the term ideal or economical.

Just as an example, merely removing the barbettes will be problematical, as I believe barbettes are usually incorporated directly into the ship's internal structure. (I don't know if this is universally true or not, so YMMV.) Removal introduces a big gaping hole in the hull strength which will then need to be filled by something. Further, changing the ship's upperworks may result in some stability issues, and it'd probably increase the overall displacement and draft, rather than vice-versa. If the hulls were purchased incomplete, a better case could be made for a conversion.

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Sunday, July 17th 2011, 8:13am

With my Columbia and Liberty I used the engines from unfinished Lexington class Battlecruisers, but that was about it. The rest of the hull was purpose built. The S.S. United States' power plant apparently was used as the prototype for the plant used in the Forrestal, so I don't see why the Iowa's engines wouldn't work in a liner.

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Sunday, July 17th 2011, 8:54pm

Hello again,

I got the idea to build an ocean liner out of an Iowa Class BB Hull after looking at pics of the uncompleted Iowa-class battleship USS Kentucky (BB-66) at this website: http://www.navsource.org/archives/01/66.htm
Looking at the unfinished battleship got me thinking: since the guns and armor and not fitted, wouldn’t this be a perfect candidate for reconstruction into an ocean liner?
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After that I started running through some numbers concerning speed and power. But first I need to address ship displacements and weight distributions. Since armor and armament are out of the question, this area needs to be discussed.
Starting from a trial displacement of 53,900 tons, removing the armor (18,700 t) and armament (10,800 t) alone brings that figure down to 24,400 tons trial displacement (13,500 t hull; 2,500 t engines, and 8,400 for miscellaneous items). Standard displacement drops to only 15,500 tons. Obviously, I will need to add extra weight elsewhere to fill in the weight loss from the armament and armor, and can be channeled into greater fuel for longer range (although at higher speed).

For example, if I want to increase the Iowa's range to 20,000 nautical miles @ 24 knots (double their designed cruising speed); I would need approx. 9,680 tons of fuel oil for this range. (I derived this by working from the associated water plane area and friction coefficient) Assuming a 10% spare fuel oil capacity (10,750 tons), that would imply a standard displacement of 26,250 tons and a trial displacement of 35,150 tons (all displacement are w/out passengers).

Giving a miscellaneous weights allowance of 12,000 tons (passengers and cargo), here is the final standard and trial displacement for my ocean liners converted from Iowa class battleship hulls: 38,250 tons standard; 47,150 tons trial; maximum displacement ought to be somewhere in the region of 50,250 tons.

Now that the weight situation is covered, attention can now be paid to engine power and speed.
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Using the Iowa’s original 212,000 SHP steam turbine engines, we can now calculate the approx. top end speed for my ships after reconstruction. Navy model testing revealed that every 1,000 tons less in displacement equates to a 0.25 knot increase in speed.

Speed Figures from original engines:
- Standard Displacement = 36.41 knots
- Trial Displacement = 34.2 knots
- Max. Displacement = 33.4 knots

Now, if we wanted to use the full 254,000 SHP overload power, here is what the figures would show:
- Standard Displacement = 39.91 knots (approx. 1.6 knots faster than the famous SS United States)
- Trial Displacement = 37.70 knots
- Max. Displacement = 36.90 knots

By any standards, these speeds are impressive (although attained at a lower than optimal displacement) and probably not attainable in service. My ocean liners can attain approx. 40 knots from only 254,000 SHP (the Big U made 38.32 knots flat out using only 241,785 SHP), the Iowa’s are close in performance to the Big U (at least when displacement is lowered enough) and I believe speeds such as these can be reached after proper reconstruction.

If any of you have any comments, feel free to comment of e-mail me at ssnormandie@gmail.com .