Aluminium boat Panama

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niko
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Aluminium boat Panama

Post by niko » Fri Apr 20, 2018 7:34 pm

Hello to all of you on the forum!

I am an Austrian living in Panama in the coastal area of Guna Yala, an indigenous area where the Gunas live. My wife (she's Guna) and me have bougth a little island to accommodate tourists and we have a 27ft fibreglass panga which i am currently repairing (picture).
Since the repair process doesn't go too well and I really start to hate the material I was thinking of building an aluminum boat.

We just need something simple; a good efficient planing hull that moves securely in high choppy waves - up to 2 meters on very low period, with space up to 15 passangers where the 90 yamaha should still lift the boat out of the water (as it does with our current boat).

i was thinking about the barracuda 23ft for that purpose or something similar. I would modify it to only using some benches and a bimini

A very good friend is a professional welder and would help me.

Any suggestions on the idea and the boat for my needs?
thanks in advance
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Roberta
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Re: Aluminium boat Panama

Post by Roberta » Sat Apr 21, 2018 7:11 am

Welcome to the forum. There are several AL designs in the Glen L catalog that might meet your needs. We also have several other builders who have, or are, building AL boats and who are really experts in metal and welding on the forum who will be happy to assist you in any way they can. All the best in your project.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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DrBryanJ
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Re: Aluminium boat Panama

Post by DrBryanJ » Sat Apr 21, 2018 9:10 am

Niko:

Maybe on of the power cats might work. Nice large open deck that can be fitted with benchs.
Bryan

Building a malahini "Mona Lisa"

My wife said "If I build a boat, she's getting a divorce."

niko
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Re: Aluminium boat Panama

Post by niko » Sat Apr 21, 2018 2:08 pm

Yes i was also looking on the cats around 22 ft. Would the 90 yam work alone and would it be enough power to move up to 15 pax planing? Also can it securle be handled on such high wind chop?

Kevin Morin
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Re: Aluminium boat Panama

Post by Kevin Morin » Sat Apr 21, 2018 11:34 pm

niko,
I'm not sure there is a panga hull form in the Glen-L catalog? That hull form seems suited to the area (widely used usually means well suited?) but there are other shapes in the Glen-L book that may be useful for your needs.

Just having access to someone who can weld aluminum is not necessarily going to allow you to build a welded aluminum boat!! There are 10 to 15 hours of cut, fit, set up and tacking to one hour of welding!!

Will you be planning to use a "cut package" boat? or are you planning to do the lofting/layout and battening panels outlines- by hand? This decision has several implications.

#1 the hand laid out hull, cut by hand after lofting the panels' outlines- is more labor, requires more skill and implies learning or having access to people with those skills.

#2 CNC or NC cut kits are less available than a Glen-L design- for example: fewer designers of welded aluminum boats take the time to do the CAD outlines (for CAM cutting) and nesting and other CAD related work. So, there are fewer plans available for NC cut welded kit boats- as compared to the plans available for wood and epoxy composite boats.

#3 welding aluminum boats is a narrow niche of welding aluminum. IF your friend has not built welded aluminum boats before (at least half dozen) then my experience says: he'll be more burden than benefit! Welding boats requires more than the ability to run a seam on the bench.

I've built in welded aluminum and tried to help others do so too. I'd be happy to try to help you move ahead here on the forum. I just started another boat this week- I'm building a 32' welded aluminum boat with a friend.

cheers,
Kevin Morin
Kevin Morin

niko
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Re: Aluminium boat Panama

Post by niko » Sun Apr 22, 2018 8:48 pm

They use the panga because its the only econmic design available and they work terrible with tourist an high wind waves. Backpain programmed.

No cnc package because there are no designs suited for our work and no cnc shops around.
We will cut by hand and ot will be quite some work. What would you recomend? Plasma, saw or anything else?

My friend hasnt build boats but has certificates in aluminium welding. I hope i will learn in the process.

We have a 1990 miller airpak 600 and a xmt 350 but need a spoolgun and a set up for tig

What do you think about the la paz 22? Could it be fitting our needs?

Thanks for all Input

Kevin Morin
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Re: Aluminium boat Panama

Post by Kevin Morin » Tue Apr 24, 2018 9:47 pm

Niko,
I'd love to be able to help you make choices but unfortunately I have too little info! Why does the panga hull cause problems? Not sure of the shapes' exact lines - mind you- but what does it do that is problematic? What exactly are you doing? Landing people in the surf on a beach in a following sea? Running in some (give an example) seastate - bows to the weather? Load size, (# of people?) speed? there are one large bunch of questions that factor in-

I'm not sure anyone here has lots of tropic island beach landing experience? I've designed and built quite a few boats that harvest 2-4 tonnes of salmon and land them on gravel beaches in following seas, but I've spent quite a bit of time working with the local (to me in Alaska) fishermen and their needs and have a pretty good idea of what these net fishing boats needed.

From your brief description- I'm hard pressed to offer any answers or point to one suggestion from the Glen-L catalog because I'm not familiar enough with the conditions and requirements? If you'd like informed advice, I'm willing to offer opinions, but they'd all be ill-informed without knowing more of your local conditions- pictures of the actual conditions are worth a great deal of text!!

Not being difficult- just cautious about discussing beach landing hulls or that type of service in latitudes that far South.

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

niko
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Re: Aluminium boat Panama

Post by niko » Wed Apr 25, 2018 5:20 am

Ok lets get more specific:

The panga hulls work fine when its glat but bump the hell out of your back when ther is eind and you go higher speeds and I thibk it has to do with the flat part of the bottom. Picture below

We carry up to 15 passenger and we where running up to 30 mph with the 90hp 4stroke ore the double 40 2strokes

We take people from the jetties about an hour of choppy waters (up to 6ft chop when winds are strong) and land them on the beach of out island protecte by its reef but in between some currents.we go against the waves and with the waves and with waves from the sides and we use bimini tops to protect passengers and my nose from the sun

If you need mor info just feel free to ask, because I know its quite an uncommon set up.
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Kevin Morin
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Re: Aluminium boat Panama

Post by Kevin Morin » Wed Apr 25, 2018 11:45 am

niko, the panga's flat spot (approaching what is called a Delta-Plate in some hulls?) or planing surface is apparently allowing you to get 15 people on step and running 30mph with a 90! that is not bad performance!

On the other hand, I can see what you're saying about impact in a chop or even if you were heading into a 4' sea- there could be some slam impact. But the flat spot allows you to beach the boat 'flat' or to beach without tipping on to one side of a V or the other. So this hull requirement does seem to be a combination of running into a head sea, but reducing impact but... needs to land while remaining upright ! That is a bit of a uncommon requirements.

I'll look at the Glen-L catalog with an eye to designs you might consider.

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

Kevin Morin
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Re: Aluminium boat Panama

Post by Kevin Morin » Wed Apr 25, 2018 12:03 pm

niko, I looked at the Glen-L La Paz 22' design and will give my opinion.

the stretched version of the boat will hold the 15 people and run well, with LESS impact than the panga hull you show- WHEN loaded- but in the light state- empty or only a few people- the very light hull will not ride nearly as smoothly as it will with a load. Further, the V of the LaPaz is 18deg (approx) at the transom so the hull will not have the same slapping as the panga's flat strip down the centerline- BUT.. the LaPaz would be expected to lay to her chine on a beach landing?

I'd expect the panga to be twice to four times the overall hull wt of the La Paz in metal- 1200 lb La Paz will likely be nearly 2-2.5 tonnes in the glass fiber version? So, where the shape is sharper below the chines (based on a guesstimate from the photos) the wt or increased mass of the glass hull does contribute to 'ride' or smooth operations in heavier seas.

Therefore, while I'd say the La Paz was a possible choice for your application (have not seen her plans or sections) - there will be beach handling differences and low loading performance issues due to how light this design will be compared to the plastic molded boat.

The biggest problem with any cat hull is the depth of keel with a given load? they are not well suited to carrying large loads onto or off of a beach. A monohull will draw less water for any given design than a cat or other multi-hull so- while the open ocean running may be advantageous in some applications for cats over a monohull- that is not the case on a beach landing. The cat will be aground many boat lengths outside the dry beach compared to a monohull- AND.... depending on the incline of the beach - gently sloping or very steep? the cat may be aground in an active surf line! Compare that to most monohulls- where they'd surf in, or power in much farther due to the hulls' cross sections- it takes more wt to immerse one inch of monohull compared to one inch of cat hull(s). So for a given load the keel is deeper in a cat and it will ground sooner -farther out- when beaching.

Just a quick look at metal boats from the posts above- will look more closely.

As to a welder with no hull experience: you will need to be very controlling of where and when beads are added! Otherwise you're project will suffer contortions and distortions not in the design!

cheers,
Kevin Morin
Kenai, AK
Kevin Morin

niko
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Re: Aluminium boat Panama

Post by niko » Wed Apr 25, 2018 8:20 pm

I really appreciate your efforts to help me!

So yes i was also thinking about that flat section giving us extra planing speed and yes our boat is pretty excepcional compared to the other pangas in the area and beaching was going pretty well, but as stated above the downsides are of greater importance for me because of the long ride our passangers have to pass on the boat. Also I really want to get rid of my plastic-bomber which I learnt to hate during my current restoration.
I thoght that I would have the advantage of lightweight , which would compensate for the absence of the flat section.
Also I would adjust speed to the loading condition so if I run with little weight I would turn down a bit the motor.
Also I would use 1/4 for the lower hull to add a bit more weight in the water. I Actually dont know our pangas weight but I know the al boat would be much lighter.
Could ther be added some extra weight with e.g. sand bags? I know that sounds stupid but.... :)

Also your indications on cats are interesting and i will drop the cat ideas for now. Maybe in the future it could be tried out.

So I am really inclined to buy the la paz hull and give it a try.
I alread ordered the al-building book to have more theoretical knowledge befor going into practice and to be able to supervise the process better.

One more thing; ther is only 5052 available for plate in Panama. Could this be a problem for the marine environment?

Best whishes from Guna Yala!

Kevin Morin
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Re: Aluminium boat Panama

Post by Kevin Morin » Wed Apr 25, 2018 11:00 pm

niko,
you are very welcome for any help I can be in helping you decide which Glen-L design is suited (in my view!) to your work.

I'm not sure of the costs/value/expense of your resort guests' trip or stay? So, my remarks may not be applicable? If, for example your guests are paying several hundred dollars per day to stay on your island- then you can afford to build in some cushioned seating to help the trip be more comfortable. Regardless of hull form- high seas by the bow, and high speed over the bottom (fast travel in rough weather) can also be softened by installed seating that has a pneumatic pedestal that cushions the ride.

Regardless of sea state and speed, seats with built in impact reduction http://www.airwavepedestal.com/ http://shockwaveseats.com/?v=7516fd43adaa https://www.smoothmovesseats.com/ may be an added feature to help your guests to enjoy the ride with less impact? Even strong young backs can be injured and even damaged by riding in high impact boats! Some active seat mechanisms may be in order regardless of the boat used to ferry guests out to your island?

Next to the boat- you could consider the La Pas 22' actually the 24' would be more applicable in my view- and cut a 'delta-pad' into the stern of the V . Instead of putting the flat plate at the bottom full length as in the image posted- just cut the bottom of the V off so there is a 10" wide tapering plate in the after 5-8' of the hull?

I know that is altering the plans but, even at high speeds I doubt the running waterline will move aft of amidships on this 24' design? So, the running impact will be on a V bottom of at least 18deg or greater- that means the impact will be less jarring- not as sudden - the V will enter somewhere forward of the aft most 8' of hull. MY point is; you could add a beach landing flat but not impact that flat when running. By locating all the flat surfaces aft, behind the leading edge (viewed from the top, looking down) of the running waterline's forward most edge.

The flat plane or 'delta-plane' as it is sometimes called would not hurt the design's performance drastically and would help her sit upright on the beach.

At the transom of the La Pas 24' (or 26'?) you could add some fixed or dynamic trim tabs and they would compensate for the 'missing' V in terms of trim by the bow. In other words: by cutting away part of the V bottom in a long narrow triangle at the stern- there would be a missing section of V bottom running surface. AND... the V missing at this location will allow the bow to raise up some- but... you could compensate by adding trim tabs - either fixed (welded bars bent to trim the bow down when running) OR use a commercial aftermarket dynamic trim tab set that could be adjusted for different running states of speed and seas, combined with differing loads.

Another change to a La Pas 24' might be considered. Short fins or 4' or so could be added to the after bottom- just inside or underneath the chines- toward the keel. These would only be deep as the keel and they would allow a full V bottom to sit on the beach level. The boat would not go aground sooner than the regular La Pas hull- they would not add draft or depth to the boat- just allow her to sit level. This keels of this type would help an outboard powered skiff shape to keep her helm more stable but will add some drag and reduce top speed a knot or two? But, she'd sit on the sand almost as well as a panga's bottom flat.

Hope this is making sense?

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

Kevin Morin
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Re: Aluminium boat Panama

Post by Kevin Morin » Wed Apr 25, 2018 11:06 pm

niko,
the three most often used marine alloy plates are 5052, 5086 and 5083 with the last two being stronger and stiffer and MORE expensive than 5052. But for your use 5052 will work fine.

One caution is to learn if the welder can use 5356 filler alloy? If he is only used to the 4043 or other 'junk' fillers then you will end up with problems.

Also, ballast is not 'stupid' if your hull needs it? BUT.... usually there are much more valuable and important cargoes that can help trim a boat other than just ballast? Water tanks, larger fuel tanks, supplies, building materials, SOMething that is worth more than just sand?

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

niko
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Re: Aluminium boat Panama

Post by niko » Thu Apr 26, 2018 11:55 am

I will talk to my friend about de 5356
Is it good enough to use 6063 for any thing else than plat like tubes and angles?

About ballast; sometimes we have higher value cargo but not always but this i think would show experience to add some or not.

I would add trim tabs and fins If I really see a problem to land and to get into good planing position. Thats the nice thing about thinking about aluminium for me; i can alway add or delete something if I need to

About cussions; i want to install some cushioned benches but our turistic offers wont be high end in the next years so these systems will stay in my mind fore future development.

I will consider the delta pad, which sounds like an intersting hybrid idea.

Something on our equipment;
We have an miller airpak 600 ac/dc cc/cv from 1990 with 14pin remote connector
A simple xmt 350 without pulse function that would use auxiliary from the airpak
A Wc 115 and a spoolmatic 30A
Also I am thinking to get a high frequency unit to be able to tig with the ac from the airpak
Would that be enough to get the boat welded or do we miss something?

With all the thanks from panama and I ordered already the la paz plans

Kevin Morin
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Re: Aluminium boat Panama

Post by Kevin Morin » Thu Apr 26, 2018 1:56 pm

niko,
you cannot NOT use any 6063 at all!!! if the alloy will be wetted- beyond above deck rails or awning framing (it's OK there but softer than 6061). 6063 has a large alloy percentage of copper to increase malleability but... in salt water that will eat the metal up! So no 6063 in anyplace in the hull or framing of the hull- but OK for handrails and awning framing if you can't work with 6061 - much preferred for all extrusions- pipe included.

Agreed, being metal you can add and subtract over time and the boat will not suffer. Something like the delta-plate should probably be built in- so the structural implications are adjusted and compensated from the boat's original framing. But it too, can be modified at a later date.

sounds like you have a variety of welding equipment- but the AC TIG side does sound kind of questionable to me? I'd say it was worth considering an entirely dedicated AC TIG power supply- built in High Freq, pre purge, post purge but no need for pulse really. I'd want to have a 300A power supply for this size boat personally but then.... I'm spending your money pretty freely!

good luck, once you get the plans please feel free to ask any questions about the metal working aspects. I have some fairly extensive posts on the Forum with explanations of some of the details used in building welded aluminum boats that may be worth your time to review?

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

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