Glen-L.com

COULD? I put a fan tail on lets say a True Grit ? Also taking the money out of it ,why Alum over Steel ? The plan part is not a problem,what I don't know is what would it upset ? Planing,balance at the stearn,what do you think? Maybe the fan could be just above the water line so it would just have the look ? Like the stepped bottoms on the gofast boats.Thanks Randy.

Tugmyway,
yes you can put a fan tail on almost any shape of hull but it may be a good idea to work out some design lines so it ends up looking like it was in the original lines.

aluminum is lighter and therefore the boat will be lighter wt, and steel thin enough to be proportional to the boats overall displacement would be fairly hard to work for the cabin but without that proportionality the boat will be top heavy.

This has happened to more than a few smaller boats; heavier metal was used above the waterline to make fabrication easier and the resulting boats rolled over. If you decide to try steel in a vessel this small I'd suggest you do a thorough stability calc set before.... you buy the metal.


here's a rounded stern on a welded aluminum boat that planes, and the stepped bottom you mentioned in your post.


and a fan tail on another planing skiff after its remodel from a square stern.



both boats side by side from the stern, one showing the single piece approach to the curved/fantail/rounded stern the other showing a pair of conic developments to end up with the more traditional fan tail.

my 2 cents

Cheers,

_________________
Kevin Morin

Pardon my ignorance: What exactly is a fantail?

I always thought that is was the part of the boat that extended beyond the main "hull" which was build kind of like a "deck" over the props? Kind of like a swim platform but permanently installed.

Steve

Steve, not ignorance at all, you may not recognize the term is all?


this skiff has a slightly rounded 'transom stern' which is about squared off to the hull.


here is the Titan model with a fantail.

Its my understanding, but not necessarily fact, that if you take a fan (Japanese air conditioning from the Middle Ages) and hold it open, then curve the two sides so they form a part of a cone, you'd get the rough shape of the 'fan tail'. That's not necessarily the last word, just my understanding.

I think fan tails are rounded in plan view, connect to the topsides smoothly on both sides of the hull, and may or may not have a 'break' or a 'knuckle' in the rise. If you search for 'fantail launch' on the 'net I think the images will confirm these hull forms.

I don't think a swim deck or platform is a fan tail, they're usually more square or boxed and don't round the stern of the hull. One other item, the fan tail is extremely safe in a following sea, the skiffs you see above fish offshore 20-25 miles in the southern Cook Inlet in all kinds of weather and they are very 'lady like' in their hulls' ability to handle weather from the stern.

besides, who doesn't like a nicely rounded stern?

Cheers,

_________________
Kevin Morin

Thanks Kevin!
I have been working on taking the True Grit and giving it the Titan look.
Love the photos,the resessed tabs are something I was also thinking about adding.
The upper house will be alum,wood,plastic?? I will build it to keep the C/G as low as i can.
Looks like you do some work with Alum?
Plans for the True Grit should be here Wed?
Let's see i now have the Sweet 16,Titan,Fred Murphy and soon the TG. I think i will cut them all up and i should be able to come up with something?? I just like the TUG look!
Thanks again for the input fromm all!
Randy.

Thanks for the lesson Kevin, now it makes more sense! Of course, now it makes me wonder if I can put a fantail on the Coastal Cruiser...HOw come every question answered leads to more questions?

Thanks
STeve

Kevin,what gas do you use ? I have been using argon for just about everything.Thanks Randy.

Also what do you think of this weld. D = dirty C = clean
I tryed your rod hand hold. Now I can't remember what I use to do??

Randy, I use Argon most of the time except when things are heavier than 1/4" then I switch to mix of 75 Helium 25 Argon for deeper penetration with same amperage.

both welds look good, I don't see any dirt in the first weld, they both have the 'gas track' or clean zone, even bead, nice toe fusion and good uniformity- what's not to like??

Many welders don't realize that uniformity is more in the off hand than the torch hand.


I used a pulsed power supply to do this weld, and the uniformity there was almost all in the power supply's controls.

Cheers,
Kevin Morin

_________________
Kevin Morin

Power supply is a Linde 250 from 1988. She is a good machine.
If in starting a job like the True Grit should i look into a better/newer machine? With me being 60 what will be the learning curve? Old dog. I don't have a MIG but looked at a Miller 140? Thanks again for the help!
Randy

Kevin will probably agree that pulsed MIG is the up and comming thing in Aluminum boat building.

_________________
Steve Schefer
Santa Rosa, Ca.

New Years Resoluiton - Never leave something for someone else to do when I should be doing it myself.

Randy, the transformer power supply if fine, you're not planning on production or high volume work (?) so that power supply will be a good workhorse. The newer inverter types (for TIG) have digital controls not available before the early 90's and not perfected until the last decade, but they are nice.

As to building without MIG? I suggest that there are many welds where TIG isn't a wise choice for the one off builder. Tacking up makes a MIG system worth its weight in platinum, doing long double sided hull seams and other 'high volume' welds is not going to happen fast enough with a TIG torch.

You'll need 225 to 250 amps minimum to weld aluminum effectively, it can be MIG welded with less but the number of issues with smaller powers supplies is legion and I'm not going into those details in this post.

I only buy Lincoln or Miller power supplies but there are imports, and perhaps some US made brands that offer competitive equipment? I really don't know as I need to be sure I can weld what I want when I want, and I don't think I'm saving buying anything that 'ain't Red or Blue'. I use Red for MIG and Blue for TIG but I have more than a few friends who use all Red or Blue?

Both companies offer all sorts of MIG power supplies and as long as they have the power rating to weld the sheet in your boat, then I'd say that was the minimum size power supply you need. Right now, I'd be looking at eBay,Craigslist and other sales sites for a 250 or 300 amp PS that was used and CV or MIG power supply. There is the best value for the dollar as many shops are moving up to the newer pulsed and 'programmed' wave form welders.

These welders are fine, I own one and I like it, but ...... they are expensive relative to the bead laid down.

As sschefer notes, pulsed MIG is big now, and Lincoln even has pulse WITH pulse, and that has a place too. But, if we're discussing building a 25' boat- one time- then conserving the building budget is important too, so buying a new power supply may not be as cost effective as looking for a good runner that is used and offered at lower cost but would still build the boat.

I'd look for a 1 lb. or pistol type, push welding torch instead of the push pull. Yes, I do own the push pull models, along with a Lincoln Power MIG 350MP, and no you can not get in to as tight a corner with a push only 'spool gun' but..... they cost 1/5 the newer push pull guns. Once again, I'm not using my work as a guide I'm focusing on the idea of building one boat, one time, and the tools needed to do that job.

If you're only building the True Grit and then going cruising until it 'wears out' then the Linde 250 with a hand torch and a 250-300 A used CV power supply with a spool gun will build a fine boat, and not break the bank.

Hope this helps? but if there are confusing phrases or assumptions that make things inconstant the please post what we can answer directly?

cheers,
Kevin Morin

_________________
Kevin Morin

Thanks! I will start looking of the other power supply. And a spool gun ,Ideas?
Also,lets say I have some tine to build. Could it be done with my Linde 250HF ?
Also what about using the Linde for the spool gun? amps to low? She is a AC/DC/DC revers.
Thanks again!
This will be a one boat build.

I see you went on to another boat. Wish it would have ended with a full build,but! It is cool you are on the water now. Other than the time,what stopped it? Number of welds,weld time,WIFE? Just kidding about the wife thing. It is just some of the things I will be looking at. Thanks for the input! Randy

Tugmyway,

http://cgi.ebay.com/MILLER-DELTA-WELDER ... 19c62c8f83

here is a very nice power supply with a gun for what is (relatively) a very low price, it is a 3phase unit- but the cost is about 1/8th new and when the boat is done you'd likely get 75%-85% of this price when you sold the unit again?

Weld time in a welded aluminum boat is about 1/10th to 1/15th the manhours. Layout, fitting and prep is the 9 of 10 or 14 of 15 hours spent depending on the level of the hull shape's details. Most metal boats are not held up by welding, but it helpful to be able to weld, they are held up by the fitting and preparation needed to get decent weld joints in materials that are less easily worked compared to wood or plastics.

http://cgi.ebay.com/Miller-Dimension-65 ... 3f0ac4b015
other items where the value is extremely high compared to pricing

http://cgi.ebay.com/MIG-Welder-Linde-Un ... 336888fd6a

http://cgi.ebay.com/Hobart-RC-301-Compl ... 27b7bc357d

any of these larger capacity power supplies will work to build, if you add a spool gun for aluminum to these power supplies then you'd have a very reliable MIG system based on the over sized power outputs of these various welders.

I'd always make sure I was able to check out a machine before buying, and crating and handling can be hard to get done remotely.

Most critically important is the wide difference in the many welder versus the power and controls of the many different spool guns. that means you can't buy any set of A a power supply and B any spool gun and expect them to 'plug and play'.

But by studying the different details of each used product you can match or make a match something that can be cost effective.

cheers,
Kevin Morin

_________________
Kevin Morin