RE: [PSUBS-MAILIST] Launch Retrieval Transport

I for one don't need a screen grab. Your explanation was great, and the principle is simple. Can you use it while telescoping only one tube? I'm also curious about what happens on shorter ramps with a steeper angle: Does the neck have sufficient ground clearance?

Thanks for responding,

From: "Smyth, Alec" <Alec.Smyth@compuware.com>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: RE: [PSUBS-MAILIST] Launch Retrieval Transport
Date: Mon, 6 Nov 2006 19:16:50 -0500

Believe it or not I can't find a photo of the extended trailer tongue. But it's extremely simple. The trailer has a longitudinal square tube running almost it's entire length. It's strong, probably 4" square and 0.25" thick walls. The square tube is integral to the trailer. Inside that is a slightly smaller one, and inside that a third. All are 0.25" walled, strong enough that you can apply some serious towing power without any fear of bending it, even when extended. So two of the three tubes slide freely. There are a couple of holes drilled through all three tubes, to take large pins (0.5" diameter) that prevent the loose tubes from pulling out. To extend the tongue, you pull the pins, chock the wheels, and drive the car forward. It does take some back and forth until you line up the holes again to reinsert the pins, but nothing major. You should have seen the support team by the end of the convention, they had it down like a pit crew. I've painted the pull-out tubes red when they have gone too far, so the driver essentially pulls them out until red paint is spotted.

It's something like this, except much longer and with two tubes one inside the other: http://shop.easternmarine.com/index.cfm?fuseaction=catalog.prodInfo&productID=5268&categoryID=226

The trailer has a flat aluminum deck, on which I've bolted two long pieces of plastic square bars which are machined so their surfaces slant inward. They help guide the sub into the center of the trailer deck and hold it there. There is also a forward stop, placed so that when the mechanical grabber on the sub rests against it, the sub is balanced properly fore and aft. So the trailer deck is "closed" on three sides.

With this arrangement, I get into the sub on land and someone backs the trailer down the ramp. When the sub floats, I motor off with the thrusters. For recovering the sub, I motor over the trailer deck until the mechanical claw touches the forward stop. The K250 front viewport is perfectly located to see when that happens. The truck pulls the trailer up the ramp very slowly, with me following by using thrusters until the trailer takes the sub's weight. This technique I'm using now is a slight improvement over what I did at the convention, which was to attach a strap to the bow before moving the trailer up the ramp. Now I launch and retrieve without either pilot nor crew getting wet. My next enhancement is going to be painting a line on the deck to help guide me to the front stop in low visibility.

Both Mark Ragan and Dan H use trailer tongues, but the difference is that theirs are lightweight, while mine is very heavily built. I'm not sure which approach is better, all three seem to work just fine.

I do have this on video, so if anyone wants to see it I can just take a still frame from that.

cheers,

Alec