Hi, I've been doing a bit of research on the option of building a aluminium kit boat, specifically one from CNC marine 6.1 hard to half cabin. Have access to a professional welder to weld it up for me but I'm just more interested in other people's experience with building their own aluminium kit boat eg quality, ride, resale values of a boat not built by a professional boat builder. Thanks!

Doesn't even matter if you have a pro welder resale will be ****e.
Designs aren't always that good. You pay full price for everything you put in it ( new instead of the very soft prices of secondhand at the moment) . Ride will be ****e as most plate boats are awefull shallow deadrise heaps of shxt. Far better off buying well secondhand. Homemade and kit boats you will loose a lot of money

Thanks for your reply. I was actually more interested in doing it as a hobby project if anything was just wondering whether it was worth it or not. When you say "most boats...", I kinda compare it against the likes of BarCrusher, Tabs, etc. So you saying even these commercially built boats don't handle well? I'm a boat novice and don't know a whole lot as I've just started researching.

Look up specmar Australia.
Rodney dredge there knows his stuff! Also look at pjm industries in hervey bay Paul Jacobson builts proper plate boats not **** ones like the ones above!

I understand the hobby thing. But you'll pay an absolute premium for what will ultimately become a chore. If a good boat is your aim, consider an old classic fibreglass hull in need of work. New floor transom paint and a modernised fitout. All still in a recognisable classic hull that will perform great and sell well. And yes even pro built aluminium (with the exception of a few) ride like ****e. Shallow deadrise, beamy, high volume, broad shouldered spine compressors.

Brother did it be he a coded welder. If you havent got the fab/rigging skills be better of repowering a old fiberglass etc.

Unless you have an advantage...really cheap materials (need to be almost free!) or you just like to build boats.

Don't do it!

I built a GRP 1/2 cabin boat years ago....hull and deck all done in two weekends, nice and easy !!! . Joining and fit out year plus later, and lots of $$$$. As it is retail marine stuff which is never cheap.

Remember in a boat nothing is square...mark,cut adjust, cut adjust....then maybe fit {or maybe toss!}

A few points, i should point out (Incase your not aware) I'm a boat yard, so i have a little experience. IM not saying i have all the answers but i can only tell it as I see it..

The CNC boats actually IMHO look okay, their is a guy in Two rocks who build them and sells bare hull and i've fitted a few hin numbers for him and i was rather impressed at the design, use of space and general lay out. I have climbed all over the 6.1 and that was maybe my fav. I recently sold a 7.5 that was completed and it was a huge hit. Sold very fast and water tested went very well also. I thought the actual welding on the boat sold to be first class and that will make a big difference when coming to sell on later. People were sceptical of it being a "Not so well known" brand but once they all viewed the finished product, were disappointed to have missed out.

So having said that, you would need to do a good job at welding. The welds must be clean and flowing. If not your throwing good money away. As the video above of Busters Bro, id suggest if you enjoy that sort of thing, it would be very enjoyable. Kind of like surfing a board you built for yourself.

You will be able to make individual changes specific to your like and dislikes.

The cost involved won't be as cheap if you make a few mistakes. Once you've got it nailed i think you'll find it cheaper, even though much of the fit out needs to be purchased at higher rates. The labour content in building a hull from scratch is high, so you should have some reasonable savings IMHO.

You do need to have the time and energy though also. Remember the time must come from somewhere, plus the space that will be required. A project like this really would be hard in a confined space.

With a CNC they come with all the specs and builders plate which is good, but you as the welder (Builder) will be responsible for that boat for its life time. Same as if you import a boat directly from overseas, your also responsible, as the importer.

You may have a little fun with insurance, but not too hard if you ask the right people. Finance didn't seem to be an issue for a CNC boat.

Hopefully that helps some.

TIP ! ....Get a long chorded push- pull handpeice

Thanks all for the good feedback :) the idea originally started out as my dad is a retired first class welder with 40+Yrs experience in all kinds of welding. It was more about giving him a new challenge to work on as he never refuses a good welding project. Totally understand about making sure weld quality is high to ensure a good build and better for selling in future. Space wise for build is the other issue which would obviously need to be considered. As for me it's easy to go out and buy a ready made boat but it is more about doing a project of my own own and getting to see the finished product (and catch done nice fish with it!)

The CNC kits look fairly professionally done and the YouTube video of the completed boat looks very nice. I'm sure the design process would have ensured that it rides and handles well like most other boats in comparison. I'm not too picky about finding the perfect boat just want something which would become a nice family cruising/fishing boat.

Doing the self build also let's me control how much I want to spend initially on fitout/motor/electrics without blowing the budget and add/remove features or accessories as required.

Well why didn't you say so. Don't fxck around. Build an 18m world cruising cat

I cant wait to Build my next Cncmarine Boat.Yes theres alot involved but totally worth every bit heaps stronger having onei of these

Way to go.

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Milsnippers said..
Thanks all for the good feedback :) the idea originally started out as my dad is a retired first class welder with 40+Yrs experience in all kinds of welding. It was more about giving him a new challenge to work on as he never refuses a good welding project. Totally understand about making sure weld quality is high to ensure a good build and better for selling in future. Space wise for build is the other issue which would obviously need to be considered. As for me it's easy to go out and buy a ready made boat but it is more about doing a project of my own own and getting to see the finished product (and catch done nice fish with it!)

The CNC kits look fairly professionally done and the YouTube video of the completed boat looks very nice. I'm sure the design process would have ensured that it rides and handles well like most other boats in comparison. I'm not too picky about finding the perfect boat just want something which would become a nice family cruising/fishing boat.

Doing the self build also let's me control how much I want to spend initially on fitout/motor/electrics without blowing the budget and add/remove features or accessories as required.

ally welding is a skill in itself, I helped a mate build one a few years back, one the hardest things was flipping the hull, you start with it upside down - have you got a solid workshop beam to sling off? Once hull is flipped you can finish the rest on a trailer

also as mentioned above push pull AC mig is a must!!! you will need a draft free shed to weld or it will cost you a couple grand in argon, practice backstepping welds with no distortion then practice practice and practice

If you have all the gear already you will save $k's

^ I think you missed the part about welding expertise lol

Dad with 40 years experience? yeah, he's probably had enough practice !

Go for it, love to see the build on SeaBreeze

I've been an Aluminium boat builder for 17 years. I've wanted to build my own for so long but have been held back by a lot of the things that have been mentioned in these posts.
- First point. The sea cant tell if a boat is made out of fiberglass or aluminium. The weight and shape of the hull are what decide how it handles. A light boat with a 2.5m beam will need to have a very shallow draft and will buck and roll with every wave (like a cork), while a heavy boat can have a deep draught and will smooth out a lot of the wave action but requires more horsepower to push it.
-Second point. I have looked at 20 year old aluminium boats that look brand new and 4 year old aluminium boats that are not seaworthy due to corrosion but every 20 year old glass boat looks like a 20 year old glass boat. Be sure to make mouse holes for your wiring during the build and always deburr the edges so the wires aren't stripped and have an "Above Ground Earth". The best thing to make aluminium last is fresh water after use.
-Third. Welding musts. No wind or draught. Push pull hand piece. Clean, clean all areas to be welded, wipe the plate with Meths prior to welding. Back step, always. Weld hot but move fast to reduce distortion. Argon gas, about 12 to 15 litres per minute.

I've just started building my own and have no regrets.

These look like fun

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mrjody said..
- First point. The sea cant tell if a boat is made out of fiberglass or aluminium. The weight and shape of the hull are what decide how it handles. A light boat with a 2.5m beam will need to have a very shallow draft and will buck and roll with every wave (like a cork), while a heavy boat can have a deep draught and will smooth out a lot of the wave action but requires more horsepower to push it.

Why not build in ballast tanks? Like Bar Crusher www.barcrusher.com.au/technology/quickflow-water-ballast-technology/
and www.barcrusher.com.au/technology/bar-flap/

(I have no idea if its good in real life, but the theory seems sound)

FYI I'm in a 20yo fibreglass...

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rod_bunny said..

mrjody said..
- First point. The sea cant tell if a boat is made out of fiberglass or aluminium. The weight and shape of the hull are what decide how it handles. A light boat with a 2.5m beam will need to have a very shallow draft and will buck and roll with every wave (like a cork), while a heavy boat can have a deep draught and will smooth out a lot of the wave action but requires more horsepower to push it.

Why not build in ballast tanks? Like Bar Crusher www.barcrusher.com.au/technology/quickflow-water-ballast-technology/
and www.barcrusher.com.au/technology/bar-flap/

(I have no idea if its good in real life, but the theory seems sound)

FYI I'm in a 20yo fibreglass...

Its very expensive to make. Also the ballast system works along with the hull shape. SO a deep V hull will ride soft but have terrible stability at rest. SO the ballast allows for the boat to sink, allowing the chines to sink and activate and add the stability back. Then you need to consider the deck level its a big bag to open up..Hence part of the reason boats like Bar Crusher and Surtees are that much more expensive..

My 2c. I got a 6.7m hardtop built. Hotwork only.Bare hull with the extras i wanted. Fitted it out myself. Painted, wired, made eskys ,bunks the lot. Builder wanted 102k for his turnkey package. I completed it with better quality gear throughout for 82k. If you are into boats go for it.

Hey im upside down Woah.
Great project to be able to make a boat the way you want. Plus you can save a bit of coin if parts are sourced wisely.

I can send you this book if you pm your postal address . Regards southace

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mrjody said..
I've been an Aluminium boat builder for 17 years. I've wanted to build my own for so long but have been held back by a lot of the things that have been mentioned in these posts.
- First point. The sea cant tell if a boat is made out of fiberglass or aluminium. The weight and shape of the hull are what decide how it handles. A light boat with a 2.5m beam will need to have a very shallow draft and will buck and roll with every wave (like a cork), while a heavy boat can have a deep draught and will smooth out a lot of the wave action but requires more horsepower to push it.
-Second point. I have looked at 20 year old aluminium boats that look brand new and 4 year old aluminium boats that are not seaworthy due to corrosion but every 20 year old glass boat looks like a 20 year old glass boat. Be sure to make mouse holes for your wiring during the build and always deburr the edges so the wires aren't stripped and have an "Above Ground Earth". The best thing to make aluminium last is fresh water after use.
-Third. Welding musts. No wind or draught. Push pull hand piece. Clean, clean all areas to be welded, wipe the plate with Meths prior to welding. Back step, always. Weld hot but move fast to reduce distortion. Argon gas, about 12 to 15 litres per minute.

I've just started building my own and have no regrets.

Why wouldn't you use a foot peddle + Tig weld it?

Hi,

I am doing research as well. This is what I have in mind: www.ctmd.com.au/assets/pdf/cat/7disp.pdf

I would like to hear from someone who already went this way with similar size boat.

My questions:

1) End price for your kit.
2) Painting: mat cost + labor.
3) Fitting: I understand that new is better, but what about used parts in good condition?
4) Trailer, specifically for the cat.
5) My Isuzu MUX has 3t towing. Would it be sufficient?
6) Do I need to register constructed boat? How difficult is it (Say NSW)?
7) Slightly off the topic, but related to the end product: Diesel outboards. Recognized brands are way out of my price range, what about other AliExpress sourced. There are plenty, but did anyone try them?

Ideas?

Thank you.

Kind regards,TY