My choice would have been a Sub chaser!

[thudpucker]

The mine sweeper design thread got me to thinking about a large hi-performance boat.

I worked in a WWII Sub chaser. Marvelous creation.
I knew it had a keel up front, back as far as the Tanks and engine room I think.

Lord knows how much talent went into the design of the ones used in WWII because there were earlier designs that didnt survive.
This one was double diagonal planked wood.

I thought I would make mine without any keel rearwards of the engine room.
I'd want the front end keel to do the anchoring for the steering.
I want the aft to skid in a tight turn. I believe you could make a 90 degree turn at flank speed in that thing if it had no keels to deal with.
If it had just enough Rocker to squat at high performance there'd be nothing but those hard working props down deep in the water. Any cavitating would pull a plank for certain.

The Sub Chaser had two huge diesels and a Hydraulicaly controlled Prop set up.
Two pairs of levers up on the cockpit (open and the guy was strapped in, because that thing would really dance around)
IF I'd been a kid in the NAVY during WWII, I'd want to be the driver of the Sub Chaser.

Each pair had a throttle and a reversing lever. Forward with all four was a drag race.
Hellavalotof noise and stuff rolling back down the deck. Pure excitment!

A turn to port was to haul back on the port levers and hold or Fwd on the Stb levers.
On that manuever, I looked back at all the wash and disturbance in the water and decided it had keels back there. That's when I got the idea I could improve on the design.
There's no rudders, just those two props in the water. With both working to swing the rear around and no keel in the way, it ought to turn on a dime.
So lets hear from the experts. I'm curious to know if I'd improve or ruin a good boat!

[mydauphin]

What was name of boat, any pics?

[thudpucker]

Sorry, that was back in 55 or 56 and the boat was a salvage sale, had gone through three owners since the war. It was being refitted for a trip to Hawii from Seattle. They did run it up from San Diego to Seattle under its WWII configuration power.
Do you keep track of those boats as a historacle project?

[mydauphin]

Originally Posted by thudpucker

Sorry, that was back in 55 or 56 and the boat was a salvage sale, had gone through three owners since the war. It was being refitted for a trip to Hawii from Seattle. They did run it up from San Diego to Seattle under its WWII configuration power.
Do you keep track of those boats as a historacle project?

No, but with name I can pull up design, performance specs and perhaps some hull lines.

Also what did you mean hydraulic prop?

[thudpucker]

A really astounding thing for WWII.

Each engine was an Upright, 16 cylinder GM 71 Cu In, arranged on a single crankshaft in a Four-bank arrangment with two intakes and two exhaust manifolds. I think it was six or eight feet tall. It had a big Air intake at the top that faced the gangway. At each Air horn was a big rack full of pillows. The function was for the black gang to stuff the pillows in the air intake in case of a blower seal faiure which woud cause a runaway and endanger the boat.
One engine on each side.

In between, about in the middle were two BUDA four cylinder diesels.
One ran the Hydraulics and the other the Electical power.


A right angle gearbox at the bottom of each main engine turned a big Bronze shaft.
About 8" in diameter if I remember corrrectly.
The Prop was a Hydraulic gearbox with blades sticking out of it.
I really dont remember looking at the method of changing the pitch, but it was done Hydraulically and the control was up at the Cockpit.
No other gearboxes in the boat.

I hope you can pull up a photo or drawings. I'd like to see it again.

[mydauphin]

Do you remember name of boat or number? Never heard of an upright 671 or this 3 of then together.

[mydauphin]

Checkout is this subchaser class your talking about

http://www.ww2pcsa.org/subchaser.html

or take a look at this one

http://en.wikipedia.org/wiki/File:USS_SC-661.jpg

http://www.subchaser.org/deck-plan-inboard-profile

[mydauphin]

ubchaser Facts and Specifications

Table of Comparison - Subchaser specifications
WWI SC-1 Class WWII SC-497 Class
Length Overall 110' 0" 111' 6-¾"
Extreme Beam 14' 8.75" 17' 11.5"
Displacement (Tons) 85 98
Engines 3 standard 220 hp Gasoline, 3 screws Two GM straight 8 Diesel (8-268-A) 1440 hp, or Two GM 16 cyl. 184-A “pancake” engines
Speed 18 knots 15.6 knots or 21 knots
Maximum Draft, full load 5' 8" 6' 6"
Armament
1 3"/23 cannon
2 30 cal. Machine guns
1 DCP “Y” gun and depth charges
1 Single 40 mm Bofors or 1 3"/50 cannon (forward)
3 Single 20 mm Oerlikon (midships)
1 Twin 50 cal. machine gun (optional) (aft)
2 K-guns
14 depth charges 300 lb each with 6 single release chocks
2 sets Mark 20 mousetrap rails, each mounted with 4 7.2" projectiles
Complement 2 officers, 25 enlisted 3 officers, 24 enlisted
Endurance 1,000 nautical miles @ 12 knots 1,500 nautical miles @ 12 knots
Facts:

A total of 440 subchasers were built for World War I.
A total of 438 subchasers were built for World War II.
Prior to the Pearl Harbor attack 84 SC hulls had already been laid down.
None of the current encyclopedias today have articles about subchasers.
No SCs were numbered from 800 to 899.
Twenty WWII subchasers (SC-449 class) built by Luders Marine Construction Co. of Stamford, CT were 110' 10" long rather than 111' 6-¾".
Elizabeth City Shipyards, Elizabeth City, NC built more SCs than any other boatyard, a total of 28. The same builder set a record for the fastest time from keel-laying to launching when it built SC 740 in 30 days.
Seventy SCs were converted to SC-C (Landing control vessels) but not one of the 19 SCs used at the Normandy landing was an SC-C.