First tin boat, and project to follow!

Been a boater all my life, and finally bought my first aluminum. She is a MonArk 1644 with 97 25hp Mercury. The motor runs really strong, and pushes her 29 mph. She has three ribs that are cracked in the middle of the boat. I'm not sure they are anything to worry about. Should I pay to have them welded, or will it just encourage more cracks elsewhere?

She will be used for all my non-kayak hunting/fishing/camping. I love to bass fish fresh water, and chase saltwater species in the tidal creeks of GA. I need a larger casting deck on the front. I plan to floor the boat with plywood that can be taken out occasionally for cleaning. I plan the front deck to be all the way back to the first cross rib, and will make an angle aluminum frame and top with plywood. She will have a transom mount trolling motor on the bow. Can hardly wait to finish her out! What do you folks think?

Hi Apex. Congrats on the new toy. That 25 hp Merc will make that thing fly. Depending on how bad the cracks are in the ribs, I would get them welded. Most shops will do them for $20, or so. However, if they're not too bad and don't seem to effect the structure, you can either drill a small hole at the end of each crack to keep it from spreading and/or fill them with JB weld. I like the idea of the casting deck too. It will get up above the water a bit and add some weight to the bow.

There are really only a few rules with tin boats:

1.) NEVER use Pressure Treated wood on a tin boat. The preservatives within it will cause galvanic pitting in your aluminum hull. Instead, use non-PT, exterior grade plywood. Aruaco is a popular available brand from Lowes/HD. You could probably use 1/2", but I like 3/4".
2.) To seal the wood you can use either 2-part epoxy, fiberglass mat & resin, or several coats of Spar Urethane. The epoxy and fiberglass are great and will make the wood last forever, but it is pricey and you often have to order the supplies, whereas the Spar Urethane is available at any home store. Some folks also just use good quality exterior grade paint. I like Rustoleum oil based enamel.
3.) Use Stainless Steel hardware throughout (preferably dipped in 3M 5200). You can also use aluminum pop-rivets to attach the deck to the ribs.
4.) As far as painting the boat, sand with 220 paper, wipe down with acetone, let dry, apply a light dusting of Zinc Chromate Self-etching primer, then paint.

As far as the removable deck is concerned, I would probably build an aluminum frame out of angle and simply attach the the decking on top with wing nuts, or other detachable hardware. I've even seen folks use pins like on the hood of a muscle car. You can even make it out of two pieces so it's easier for one person to lift out.

Good luck. Keep us posted.