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anybody have any experience building boats? i want to build a 16 or 17 foot power boat and was wondering what type of welding would be the best for marine use and make the best seal if there is a difference? also do you think a sheet metal boat with possibly something like a used car engine powering an i/o system work? one lat thing how much do u think an ok welder, plasma cutter and the other tools necessary for building a boat cost?
Reply:If you are going to build a boat the best route for a boat that size is to use aluminum.  Using sheet metal is not gonna provide any longevity.   I have seen a few stainless boats over the years that were nice but I would imagine that would be cost inhibited.  The better welded aluminum boats use .100" - .125" material from what i have seen, and the best way in my opinion to weld it is going to be a tig.  A spoolgun is going to be quicker, but in my opinion the welds will not look as nice, and not equal in quality as a tig.   I have built two small 15' jon boats aver the years, and I will tell you now a boat is quite a project.  There is alot more that goes into one than you think.  My suggestion would be to start searching the web for boat plans, and pick something you like.  Then atleast you know you have a solid design.  as far as price goes, lol  You can probably buy a boat for what all the equipment will cost, but at a minimum you will need a couple grinders, a welder, a plasma to cut the aluminum, and a ton of clamps.  To get started buying new equipment I would say you would be in the $5K range buying entry level machines.as far as "Sealing" any weld will be water tight if it is done correctly.  I also think you would be better finding an older outboard than trying to retrofit an old car engine to run a stern drive.  cheaper too in the long run.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:Guys, I know this is sacrilege, but be easy on me. I'm just trying to give some good advice.If I were to take on a project like that, I would go with wood, blue foam, and glass cloth/epoxy. I would go that route even though I already have the neccesary experience and equipment to build in aluminum.Aluminum is somewhat appealing to me. I own an Alumacraft bass boat, and love it. Wood and composites are MUCH cheaper, easy to work with for a beginner, and only require some basic tooling. I like the way a wood framed boat "feels" too. I've built two small boats, a 12' Mckenzie driftboat for trout fishing tailwaters, and an 8' hydroplane named "MiniMax". Both were built using some wood framing, 1/4" exterior birch plywood (~$10 a sheet compared to a couple hundred for Al), fiberglass cloth and epoxy resin. I built the Minimax in a single day, by myself, and painted it a few days later.You should find some plans. There are plenty available free on the net, but I would strongly suggest buying some full-size plans and following them exactly. I would also suggest reading a book or two on boat construction. It would make your project go ALOT smoother, and be alot more fun.It wouldn't be a bad idea to tackle a small boat like the Minimax first. It can be built for less than $100, and would give some very ueful experience. The plans are free on the net, just google "minimax plans".I wish I had some digital pics of my two boats, I've sold both. I sold the Minimax to a buddy though, I'll try to get by there and take a pic or two.You end up with a nice, very solid boat to be proud of.Miller EconotigCutmaster 38Yes ma'am, that IS a screwdriver in my pocket!
Reply:Joe, I totally agree with you.  I have been playing with boats/race boats for years and think a beginner would have a great deal more success going the wood/fiberglass route as well.   I had my mind programmed for metalwork and that didn't cross my mind, but that is some very good advice I agree with.  Start small and work up.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:I concurr with the above posts.Since I'm a boat mechanic of over 27 years(welding/machining is my hobby/side business) I feel like I'm compelled to voice my silly little opinion.Fact is, there are hundreds of plans available for all types of "homebuilt" boats in wood/fiberglass/epoxy construction. For metal hulls... not so many.One thing I know... A good welder not only knows how to weld, but also "when not to".  I come across this issue frequently in my shop.  I'm an "OK" welder, but I'm a really good machinist. Often... I'm better off to make a new part, than to try to weld and make an inferior component.The point is... It's no sin to choose another construction technique, and any inadequacies you may have for not welding the hull will disipate quickly once the fish get loaded in the boat!  OR... I could be wrong The best things in life all come on a stick!
Reply:If you want to build a boat, especially for a beginner, wood and glass is the way to go.  Now if you must have an aluminum boat but want to do the interior stuff yourself, consider buying one from a smaller manufacturer like F&F in Monticello, AR.  Then again, just lay it out like you want, and have them build it.  they build a very solid jon boat.
Reply:Another idea that has not been mentioned is to find a hull you like. Top can be gone, burned, rotted, etc. Just buy a hull. Get a fiberglass one. Then, make all the nifty parts for it you want, customize it to death. You will spend a fraction of the money you would spend on making your own hull. Buying a factory made hull will likely give you a much better riding hull than whatever you can make, and the construction will be better on the hull itself. If you insist on welding up a hull, 5052 aluminum is the ideal way to go for the skin of the hull. shapeable, and strong, while still a marine grade aluminum. One 3/16" sheet is gonna cost you a few hundred dollars, and you will need quite a few. So get ready for some wallet shock. I have well over 40 in my boat now. Maybe 55K total. And I still want to do more.....And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:A sheet of 3/16 would be 600 to 800 dollars...at least here in NY. Just thin 16 ga. is $300 for a sheet of 4x8. It would be cheaper for him to buy a boat, as you suggest Roj-garden.  John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:A boat is a hole in the water you pour money into. The bigger the boat the bigger the hole in your wallet. I own three boats now, used to be five.Four common building materials for boats; wood, steel, fiberglass (frp), and aluminum.Fire resistance (best to worst)1 Steel2 Wood3 Fiberglass4 AluminumSteel is not really suitable for a boat less than 30 feet long.Wood, good quality boat grade wood, is hard to find and not cheap.Fiberglass is very easy to work with and make repairs.Aluminum will probably give you the lowest weight of any material for a 17 foot boat. Except when you want to use a car engine and i/o unit. A two stroke outboard will give you the lowest weight and fastest boat.Here in Virginia Beach, Virginia you can find 17 foot fiberglass boats with a motor and trailer for less than $1000.I want to build an aluminum boat also! Overall it is just not practical. I have spent 6 months looking for 5086 or 5456 aluminum for my project. I found 80 sheets of 3' x 8' 6061 1/8" for 50 cents per pound. It is just not suitable for salt water because it contains copper. I want 1/4" plate but all I have run across so far is 3/8" or thicker, even some 3" thick plate. I have not priced this new because I know it will be so expensive I am better off to use fiberglass. Still I do want to build a 24' aluminum boat so I am still looking for material.
Reply:What the heck, I got 2 cents! Automotive engines are entirely unsuitable for any boat. While there may be a very few interchangeable parts, you would have to command expert knowledge of both automotive and marine engines to discern the difference. Why not go with a simple used boat that has appeal to you, especially if it will be a first boat? I am on my first (and sometimes hope my last) boat! City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Originally Posted by tanglediverWhat the heck, I got 2 cents! Automotive engines are entirely unsuitable for any boat. While there may be a very few interchangeable parts, you would have to command expert knowledge of both automotive and marine engines to discern the difference.
Reply:The site The sheetmetal shop .com has a good forum on sheet metal boats though not welding them but seaming and riviting there are plans but for dingys rather than 17 footers ,Served my time in a shipyard so if its not made from 1/4" plate it just doesnt do it for me .Marky
Reply:JRFV & tangledriver - you can't post and mention you have boats without listing their power source!  Tangle - that looks like a 225 or bigger V-6 on the back of yours, nice boat! Dewayne - I think they use a totally different intake and exhaust system, meaning the piping, manifolds, etc. Isn't part of the exhaust side routed into the water to act as a muffler?John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:I suggest you look at 5052 and 5086 for a boat.  Most of the manufacturers in Arkansas and Louisiana use 5052.  There are at least 2, maybe 3 or 4, in Louisiana, that build the flat bottom mud boats that use 5086 exclusively.  Gatortrax and Go-Devil I know only use 5086.  GatorTail and Pro-Drive may, but I'm not for sure.  If you are not familiar with these boats, I suggest you check them out.  They are built like sherman tanks to take a beating in the bayou down there.
Reply:Tangle - that looks like a 225 or bigger V-6 on the back of yours, nice boat!
Reply:I own a 20' SeaOx with a 115hp Yamaha 4 stroke outboard, and two 19' SeaOx's with 40hp Yamaha 2 stroke outboards. Outboards are hideously expensive. I paid nearly $9000 for my 115 in February 2004. I think the 40's are at least $4000 each now, and both of mine are worn out. The idea of using a car motor with an out-drive is appealing from a cost perspective, if you can find a good used one cheap. You can get a rebuilt 350 Chevy long block for about $1000. You can even get rebuilt Mercruiser  out-drives in the $2000 range. A 4.3 liter V6 Mercruiser weighs around 900 lbs, and all that weight is right in the stern. My 115 Yamaha weighs about 450 lbs, and if it was a 2 stroke it would weigh about 330. To successfully use a car motor you need to set it up for fresh water cooling, which means 2 cooling circuits. If you use raw water cooling you are going to have problems because you need to limit the engine operating temp to less than 160 degrees, or salt deposits will form inside the cooling passages of the motor causing overheating and seizure. Even fresh water lakes have mineral deposits that will cause problems. Also, cast iron exhaust manifolds don't last long in salt water and are a pain to replace.
Reply:Those Coast Guard approved oars gotta be worth 1 manpower or 1/2 horsepower. John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Originally Posted by MicroZoneJRFV & tangledriver - you can't post and mention you have boats without listing their power source!  Tangle - that looks like a 225 or bigger V-6 on the back of yours, nice boat! Dewayne - I think they use a totally different intake and exhaust system, meaning the piping, manifolds, etc. Isn't part of the exhaust side routed into the water to act as a muffler?