Custom Aluminum Towboats

The concept was simple. We wanted the best towboat available in the US, and weren't willing to make a bunch of compromises. It had to have the following specifications:

- Hull must be made from marine grade Aluminum Alloys, of welded rather than riveted construction.

- It must be capable of mounting at least 2 separate, independently controlled TowMeUp.com Supertow payout winches, with the ability to install a standard winch for testing and verification purposes.

- It needed to have very strong hull bottoms, preferably 1/4" thick.

- It must be able to travel at speeds of 60 MPH or more.

- It must be able to handle rough water at speeds around 40 - 50 M.P.H. and should be capable of decent offshore performance in high seas. Some of the worst sea conditions in the world are found close to us at the mouth of the Columbia river as it crosses the bar, and our vessel must be long and strong enough to traverse the bar in most conditions. It must have a deep V hull configuration to slice through large waves, rather than bounce across them.

- It must be able to hold 6 people and ideally be able to carry 12 or more to get pilots to more favorable launch sites if winds or conditions required it .

- It had to have more power than Enleau O'Conners boat, and be as fast or faster, yet retain better performance and handling (no small feat since Enleau chose to install a very high performance 377 Scorpion drive system in his boat).

- It had to have an inboard outboard drive configuration, V8 power, Bravo 1 outdrive, fuel injection rather than carburation, and power steering, preferably with 2 steering stations.

With these needs in mind our staff set to work to create the best towboat available in the US, and possibly the world. Follow along and see what type of progress we are making. Keep checking back, we hope to have Bi weekly updates on the progress.

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Here's our R&D engineer Stuart Caruk working on the boat drawings with a CAD system, in this case frame 3. You can see a PDF image of the 3D Towboat drawings if you would like (requires Adobe Acrobat viewer to be installed on your system). Having access to CAD drawings makes adapting items to fit your boat much easier. We took the really easy route and were fortunate enough to find a world renowned Marine Architect and boat builder Stephan Pollard who was able to adapt a well proven hull design, and a unique cab to match our needs perfectly. This gentleman has been a wealth of information and assistance and I'd recommend him, his company, and his drawings highly. You can see some of his other products at www.Specmar.com

Stephan has also authored a really good book on aluminum boat building, which has a wealth of information for those like us who like the do it yourself, and get exactly what you want route.

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After all the drawings are completed, they are transferred to a Nest and then automatically cut out on a computerized shape cutting machine. Most aluminum boats are either hacked out by hand with skill saws and sawzalls, or automatically cut on a plasma cutting machine. Even though we have a CNC Plasma cutting table in house, we elected to have the parts cut on a waterjet cutting machine to allow tighter part fit up, with very little pre weld cleanup required. This process uses a 55,000 PSI stream of water mixed with garnet powder to rapidly cut the material and leave an edge that looks like it has been sanded. This is what the parts look like as they come off the cutting table.

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Once the parts are cut out, the building process begins. Here the hull pieces are laid out. At the rear is a flat ski (we added this to the hull to reduce chine walking, and give a higher top speed. A 3/8" thick keel is sandwiched between the 1/4" thick bottoms. You can't see it in the photos, but before we cut the parts out, we etched reference lines onto all the parts to help locate them without needing to take any measurements. Essentially you stick the parts together, line up the marks, then tack weld the pieces together.

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Here we have laid frame 4 in place onto the reference marks, and are using this as a guide to pull the bottoms up into shape. Everything is tacked in place as we work our way forward, no fancy jigs are required. Careful planning keeps weld distortion to a minimum. Using a Lincoln 300 Pulse Arc Mig welder with a CobraMatic gun doesn't hurt.

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The hull bottoms are pulled together and tacked in place, then the interior frame members and stiffeners are added and tacked in place.

The rear stringers and stiffeners are tacked in place along with the pre bent transom. The outer chine strip is tacked in place, which will be used to locate the upper hull sides.

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On the left, you can see that the lower hull is pulled into place, and the right upper side is being tacked in place. The photo on the right shows the hull shape pulled together and tacked. Note the tight fit, and the really nice compound curves formed into the hull. All this, and that hull is 1/4" thick. We were impressed! This is where getting a really good set of CAD drawings is worth every penny.

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Here's our weld inspector verifying that the hull pieces are all tacked together, ready to be welded out. She's also the lady that sews up most of the TowMeUp.com tow bridles, and is currently a P1 paraglider pilot. At this point all interior welds will be completed, and all hull seams will be welded continuously. The boat will then be flipped over and the seams cut back to clean metal with a skill saw, then all seams will be welded completely from the outside with a final cover pass. The boat will then be flipped back upright, placed on a trailer, and the upper hull will be completed.

If you have any ideas on a really simple way to pick the boat straight up, roll it over, and set it back down; be sure to fire us off an Email with your best ideas.... We're all ears.

We are also having our engine professionally built by Mr. Bob Brown. Based on a Chevy 350 powerplant, it will be bored to 383, have a 400 series SKAT crank and flywheel installed, H beam rods, flat top pistons, Trick Flow aluminum heads, roller rockers, solid lifters, and Multi port computerized fuel injection with a programable rev limiter. It should be good for 525 HP at around 6800 R.P.M. We plan to mate this to a Bravo 1 outdrive with a very heavy duty drive coupler.