26' Center Console

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Adam
Posts: 5
Joined: Wed May 18, 2016 2:31 pm
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26' Center Console

#1

Post by Adam »

I've started to build my first aluminum plate boat. Everything is being made from 1/4" plate. I've been in the metal working/ machining industry most of my life but this is the first time I have worked with aluminum like this before. Interesting to say the least. As I go through this process I realize that I would do some things differently if I were to build another boat. The one thing I regret is not cutting the skeleton, hull, and side plates from one solid piece using a laser or cnc plasma. I designed the boat with 2D software (Aspire). What does everyone else use? What software can I use to design the boat and deconstruct it to make the cut paths?
Thanks,
Adam
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kmorin
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Re: 26' Center Console

#2

Post by kmorin »

Adam, boats are about curves; even plate boats - and a pure 1/4" scantlings boat sure does qualify as a PuLLATE boat!!! Wow, think she'd be tough enough?

going into the FreeLance Farm-uh-Sue-Tical business? Working from the Texas shore south? For goodness sakes a pure 1/4" boat this size will sure be one tough tomatuh!

Seriously, the pictures show some faceting, and that is hard to overcome unless you use software that incorporates 3D Bezier curves. If the software of design is not a marine design package- and you know how to make decisions with that particular software? Well you can run into shape problems, and that can result in weight and balance headaches farther along the boat's life.

I notice in the photos, several items that could be my mistake looking at the images, but if not (then) the images show some basic new designer/builder issues you may need to address.

First, overall building sequence usually means you shape the entire boat, frames, longs, plates and all before an serious weld out is performed. The reason is that aluminum's radical heat movement characteristics imply radical shape changes. As the metal is welded it expands and contracts - 7x the rate of steel just as comparison.

That heat of expansion and the -3% to -5% contraction- converts to serious distortion of the boat unless its planned for in the assembly and weld-out sequence. For example, if you have the chine flat tied to both the topsides lower edges (hull's sides on) and the bottom (bottom panels tacked up too) when you weld it to either of the larger plate surfaces, they will act to constrain the chine flats' cooling contraction. On the other hand, if you weld to one side (bottom) or the other) topsides- BEfore... you tack to both sides? it will almost surely wrinkle and distort in into 'waves' along its length.; making adding the eventual topsides chine a real chore. Not only will out of sequence welding cause shape problems, the surfaces are VEry hard to keep fair if the weld sequence is not considered carefully before applying heat.

So the principal most builders use is to 'trap' or secure All surfaces' edges to one another,adjacent plates to each other- and all the framing prior to an 'weld out'. Weld out is a critical phase, but if applied out of sequence? the risk to final hull shape is too much for most builders to take.

Next is the idea of curves, both flat and in 3D, the hull you show may have some curve hoggs? Hoggs are kinks, angle points, facet intersections and are generally not accepted in the lines of most hulls.

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Here the curves of both the inner and outer chine are 'fair' there are no angle points, no facets, no hoggs, nothing to interrupt the smooth flow of the curves. That is because the curves were drawn in a hull modeling software where curves are critically featured software tool. There are so many curve tools in this software that one might generalize and say they were the most important feature(s)?

How do curves apply to your work? I'm not sure of the software that you used, but it seems the bottom's Delta Plate is almost a rectangle and a triangle? I'd have expected the forward 1/2 of the D'plate to be curved in Plan View? I see your hull transition has more or less straight lines along the tapered sides forward?

That translates to reduce or eliminate the bottom's cup/camber/shape in a curve which then makes for further shape compromises. If this (plan view) flat plate at the keel on the bottom were more curved or rounded in its taper forward- then the two adjacent panels' overall shape could be different, and the camber would allow the adjacent bottom panels to weld without wrinkles due to counteracting stress in the curved intersection lines.

The chine's edges (both inner and outer) appear to be a series of lines intersecting, and not a fair curve? This will translate into the adjacent plate's surfaces which cannot be smooth and fair- instead they will have to assume the faceted angle points induced by the shape of the chine flats' intersections.

Those are the first items I notice looking at your posted images. I'm using Rhino and Delftship Pro, and sometimes for some jobs I use Autocad as well.

cheers,
Kevin Morin
Kenai, AK
kmorin
kmorin
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Re: 26' Center Console

#3

Post by kmorin »

Adam, I forgot to include a Welcome Aboard, not many new members have the courage to get out of the comfort zone, spend millions $ to gear up with metal and welding equipment and then design and build their own welded aluminum boat!

Thanks for posting, let me know if I can help?

Cheers,
Kevin Morin
Kenai, AK
kmorin
Adam
Posts: 5
Joined: Wed May 18, 2016 2:31 pm
7

Re: 26' Center Console

#4

Post by Adam »

Thanks for the response Kevin!
I tried to do a few things to help myself with heat distortion. To be honest, going with all 1/4" was my first step to minimizing wrinkles but as I got into the build I realized that weight was becoming a factor for the equipment I have. When the hull and sides were put on I estimated the weight to be around 1500lbs. At that point I was baffled as to how I was going to flip it. I decided to weld out the seams because I didn't want to bend anything during the flip...
I ended up hanging the bow from the rafters of my shed and the transom from my Hi-Lo and giving her a flip. After going through that process I highly discourage it! At one point the boat got away from me and almost took me out. Next time I will build a gear reduced rotisserie.
Thanks for the advise on everything, I will definitely be checking out your recommended software.
Adam
Posts: 5
Joined: Wed May 18, 2016 2:31 pm
7

Re: 26' Center Console

#5

Post by Adam »

I've pretty much finished up my first boat build... Unfortunately Michigan weather rolled in and stomped my plans of a December maiden voyage. I was able to get it in the water this summer and check out the water line so at least I know it floats :) I still need to mount the hard top and wire the motor but that's going to have to wait until the spring as the boat wont fit out my shop door with her top on.
I was able to hold true to my "1/4" material for everything" plan. Its a true plate boat.
What do ya think of her?
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Chaps
Donator '09
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Re: 26' Center Console

#6

Post by Chaps »

Beast Mode! The only thing you'll need fenders for is to protect the docks
1987 24' LaConner pilothouse workboat, 225 Suzuki
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please view and like: https://www.facebook.com/bottompainting/
kmorin
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Re: 26' Center Console

#7

Post by kmorin »

Adam, Chaps brings up a good point! All 1/4" plate is surely building strong- a beast she is.

Here are some observations, I've argued my position against diamond tread decks on the Forum before. I've had experience with embossed plate and most of it negative- I used in on commercial fishing boats and that included a few decks. The sand and grit from boots in and out of the commercial boats sort of smoothed the traction out or the original material - and the alloy we used was 6061- those factors made for problems in the commercial fishing use of the skiffs. So I hope the deck works out for you- I realize you're not intending net fishing off a beach with your boat. Is the deck coated?

Did you use 1/4" plate to line the topsides? Whoa, heavy duty all the way! Are the double wall sides air voids for flotation? I've done a few boats in this size range that were double walled - not even the outer sheet was 1/4" though! If you did make the sides into air chambers- how much air pressure did you test the welds to?

I prefer to weld the rub rail extrusion (1" or 3/4" pipe in the photos?) continuously so they're sealed and water doesn't stand inside the 6061 material - stagnate/de-areated water gets after 6061 pretty quickly - so seal welding usually has been worth the time.

I notice the aft two legs/ladders on the hard top are pretty thin compared to the ht. What lots of top builders do is to put a small 2nd pipe just a few inches off the ladder's main tube/pipe for a hand hold. Then by strutting the smaller hand hold pipe to the main vertical pipe (ladder sides/columns) they make a truss that stiffens the top's legs quit a bit. I see the Y braces at the top but since they don't reach down very far - they'd only be head knockers is they did- the truss/hand rail is a common method if they turn out too flexible running into a head sea? Not sure if the top's supports will be completely free standing or tied to the console? If they're connected to the console that huge welded locker is usually enough to stop and flexure- if free standing of standing on the gunwales- that's when the 'slenderness factor' usually comes into play. They're trussed by the rungs side to side- but not fore and aft- and that's where I'd expect some flex if it were to happen?

I see an access hatchway down the deck fore and aft? Not sure how this is sealed? or if you're planning a wet bilge? Almost all the builders of this size skiff have had to face this question- leave access to the bilge and the control conduits OR seal weld the entire deck and use a saw to get access? I've gone both ways over the years and will report that I've yet to find a really bullet proof screw-fastener-sealed deck plate. I'm not saying I haven't tried gluing, screwing, and other forms of (long time between opening) sealing hatches of this access panel type.

I'm separating this type of long term sealed hatch from one that is hinged with latches and sealing strip that is planned to be opened anytime and loaded or unloaded. I'm referring to the deck panels that get put down and left year to year- but are removable for inspection and maintenance; these latter types have yet to find the 'best practice' in welded boats - that's why so many quality builders have decided to weld 'em shut- cut 'em out.

Speaking of welding in and cutting out: using angles for transverse frames has some built in headaches for welding. At the deck line- where the deck plate meets the sides- angles, even pretty large angles leave a difficult place to weld. Between the inner surface of the topsides and the 'outside' of the angle extrusion is a space the has to be sealed if the deck is sealed- and getting any aluminum welding torch into that space is hard to do! I was involved in a skiff many years ago where a similar design was used. The owner finally cut the side ribs off at the deck line and finished the deck - then put the pieces back on top of the sealed deck to weld them back in the boat. I'd been arguing with him that he didn't need side to side ribs - maybe under the deck ? but not for the topsides- so we ended up putting a few back in and leaving out the rest. They were unneeded.

In your case I'd say that the 'boxed' sides or double sides make the angles used as side ribs - unnecessary? A side rib is there to resist force of water pushing in toward the keel- So the idea of ribs is a 'stiff place' along the side sheet to resist the side 'folding' in so to speak. Now, in your boat's case any movement of the sides to fold in would "hinge" at the deck. That means potential movement (almost purely imaginary in your case due to thickness) would move the top of the sides (sheer line) inward- but there is a 6" or wider plate at this point. So, with that guard deck/sheer clamp/gunwale plate welded at the top of the sheet, there's almost not force great enough to push the side in. What would happen is that any force great enough to push the side in- would simply move the entire skiff away from that force.

If the push was from both sides- the boat would simply lift up before the sides would fold in- just because they're 1/4" & they have a top plate/sheer clamp to resist that force. But in what you show... there's a whole lot more.

Still need to picture the forces and movements of the boat's parts to make this point clear. The boat is loaded, its afloat, and the water or wave action against the side is providing a force (somewhat related to the overall displacement vs buoyancy forces) inward at the top of the sides. I've tried to say that in a cross section of the boat- we could call that a hinged rotation at the deck line- resisted by the sheer plate as a horizontal bar bending 'the hard way' on edge!

Now, that same rotational 'movement' (theoretical only) would also result in pushing DOWN on the inner side plate! That is trying to compress, on edge, a 3' tall sheet of aluminum. That inner sheet results in a triangular box beam that is so stiff -by itself- that the angle side ribs seem to be unnecessary. Long winded attempt to explain my remark and point of view about the side angles.

I'm not sure how dry she'll be without a side or spray rail, the chine flat is relatively narrow forward. As a result, while it will deflect spray from running up the topsides, how much will get by remains to be seen? In a low chop, or flat water none of that matters. The only time this may become an issue is when you're in waves deep enough to immerse above the chine. Lots of builders don't like the looks of spray rails but even some leading builder's skiffs are wet ("snot nosed" in the old down-east fisherman's terminology) depending on the sea state and heading in relation to the wind- just due to the lack of spray rails.

The bow of your skiff has more rake (lean forward) that most skiffs her size so that combined with the generous flam (some call side-lean flare) should help to shed water running up her bow in a head sea. The combination of bow rake and flam do make for more 'spoon' (looking at the bow's changes in waterline as the bow is immersed img#1491) so that shape may be enough to shed all water? The protruding pipe at the sheer will also help shed water outward, but once its that high on the hull usually a breeze will pick some amount of spray up over the bow?

Did you say what engine you're using? What tankage you've decided to install and where you're putting that weight? I see two control conduits in the bilge and wondered why not just one? Always end up fighting with cable end plug sizes, cables bend/turn radius vs pipe bends/sweeps and sealing the ends of open conduits- so any remarks on your methods would be welcome and informative.

Merry Christmas, congratulations on getting this far in your build. More pics, especially details, are always welcomed and thanks for posting your progress pics so far.

Cheers,
Kevin Morin
Kenai, AK
kmorin
Adam
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Joined: Wed May 18, 2016 2:31 pm
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Re: 26' Center Console

#8

Post by Adam »

Kevin,
Thanks for your observations. Learning from this forum has been one of my best resources so far in this build.
I'll do my best to address some of your concerns.

Diamond tread floor was my last choice... What I really wanted was Slip-Not. Ended up being about 1000$ per sheet and my bank account wasn't having any of that. My second choice was a "Metric" or "3 bar" plate. Couldn't find it near me. So I went with diamond plate. I coated it with truck bed liner. So far it seems to hold up ok but time will tell.

I used 1/4" plate for the insides. I actually used 3/8" for the back 8' part of the top rail. The double walls are not flotation but could be. I seam welded the floor to the inside of the hull before I put the inside walls up.... The boat currently has no flotation. My thoughts on that were that I didn't want poured foam to suck up and retain water. I have heard too many horror stories of boats sucking up water and becoming twice as heavy as they were when they were built. I still have the option of adding foam under the deck or pouring it in the walls if I find it necessary.

The rub rails inside (1") and outside (2 1/2") are seam welded with an opening aft to let water drain out if any would happen to get in. (didn't post an updated pic)

The ladders/ hard top are still a little work in progress... I will be attaching the front legs to the center console. The 2x4 in the picture is equal to the height of the top of the center console when mounted. It is definitely a little wobbly right now. I still need to add one more set of vertical poles. These poles will be just behind the leaning post seat. I'm going to wait till I can get it outside and get the top on the boat before I weld the last set of poles in. I appreciate your concerns and still have some problem solving do address in this area. Did I mention that I built the hard top from 1/4" plate also??? We should actually call it a second story;)

The access hatch is not sealed. It is not currently a true wash down deck. I left that open for two reasons. #1 Possibly add foam later. #2 all my wiring and hydraulics are below deck and might need to be accessed again. I could probably seal it if I wanted as all the screws are drilled and tapped in 1/4" wall square tube.

The water spray impact remains to be seen. I am hoping that the "spoon" shape will deflect most of it. I will be disappointed is it doesn't. It was almost impossible to get the 1/4" aluminum to form a compound bend in that shape.

I am running a 250hp Verado. I put a 50gal tank in front of the center console. (I know I probably went too small) The black barrel in the floating picture is full of water to represent a full tank of gas.

The two conduits are there because thats what I had laying around at the end of the build. The larger one will be used for the larger cable ends like you mentioned. The smaller one is for electrical wires but I mainly wanted to install it because I didn't want to run out of room in the future. I didnt seal the conduit ends. I cut them at 45 degree angles on the end. One end leads to the rigging tube and the other end goes up into the center console.

Thanks for your comments. Everything I have done on this build has come from my knowledge of reading books, forums, and watching you tube. I wish we lived closer so that I could sponge some of your knowledge in person. It would be nice to work with someone who has gone through a boat build before.


Happy Holidays!
Adam Nowak
Caseville MI
kmorin
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Re: 26' Center Console

#9

Post by kmorin »

Adam, thanks for the reference to Slip Not products! Wow that's some nice material and shows that tread plate- embossed with the raised patterns is not as effective as the metal on metal coating. Nice product, not something that will be used widely until its better known but sure does look like it would do the job on a slick deck.

What I was noting, about the deck, was that if you'd used flat plate/sheet and coated it? the traction would be the same- maybe better? We'd gone around the embossed plate with raised patterns for traction on the Forum before. My experience was that tread plate was actually dangerous in hard durometer boots or cold conditions where softer boots- that might 'grip' the raised patterns- were stiffened and therefore "skated" on the raised areas.

Anyway- if the deck is coated - then the traction comes, like Slip Not, from a coating - regardless if the coating is paint with some sand added- or bed liner or 'wing walk' troweled on? So I guess I was noting that a smooth plate with coating would have been less overall effort? At least that's my take.

We've already heard me rant about air voids and foam so I'll try to rehash my old rant as shortly as possible not to take up that much space to argue the same thing again.

If there are no voids the boat will sink once the boat is filled to the gunwale.
IF a boat has voids that displace water from getting into that volume; the wt of the water displaced will remain as lift- resisting sinking somewhat.
If there are enough voids or water displacing volumes that weigh less than water- added together they may have enough buoyancy to float the swamped boat?
If a void has foam in it- then that void will displace water if the hull is filled to the gunwales.
However the wt of the foam is much greater than the wt of air- so... a foam void will not float near as much as an equally shaped air filled void.
If the hull has voids that are filled with foam so there is some catastrophic flooding state 'protection' then the foam can produce conditions of corrosion if any water, even moist air gets into the voids/tanks.
In order to protect voids that will contain foam from allowing water in- 1000% of all welds involved in sealing the void must be air tested to insure no pressure OR Vacuum leaks exist to allow water in.
Once you have air tested a void- repaired all the weld flaws and produced and air tight chamber the foam is now totally superfluous.
The walls or hull elements that form the void are the same wt. regardless if foam is installed or not.
So adding foam to a void to displace water in a catastrophic flooding condition in a welded metal boat (>20'LOA) is totally misunderstanding the use and purpose of the flotation exercise and it's unneeded once the boat is properly prepared to hold the foam in a welded void.

Foam is required in boats under 20'LOA by regulation as near as I know? However, part of my rant is that the entire idea is just plain non-nonsensical due to the steps needed to keep the foam from being an active contributor to a leaky void's corrosion cell creation!

Foam in aluminum tanks or voids would do more damage in creating a crevice cell than taking on wt!! Your boat already weighs about 2x what is needed too in order to be totally strong and durable!! Foam is would not be nearly as wise course of building as weld pressure testing the voids you have.

Air testing the sheer welds to 3psi and TIG floating or gouging and reworking any pressure leaks is a valid way to confirm the extrusion to hull welds when they are continuously welded and expected in larger boats.

The weather top attachment to the console will go along way to adding stability but the plate top will likely increase your roll a bit. That much wt. that high will slow the rate of roll somewhat; but will reduce the roll-over point. The roll-over point is the angle of heel (chine down/sheer down) from which the boat won't 'come back' or right herself. I'd say if you find that a day fishing your boat in a swell is extremely tiring that the top is a big contribution due to excessive roll angle?

The deck hatch strip being left unsealed leaves some serious corrosion sites for you to consider? The lap between the plate and the underlying supports not being water tight means there will be an automatic crevice site formed- which is why I mentioned that many builders weld these closed and leave them to be sawn out to reopen.

Since the two conduits hold all the wires and hoses (??? I infer this is the case ???) you can't get inside the pipes from the bilge anyway so covering the access with welded plate isn't out of the context for getting to the pipes? You can only get to the bilge conduits from their ends anyway so leaving them exposed is not clear to me?

My remarks about sealing the conduit ends were to seal that portion of pipe rise that stick above the deck, either end, with their wires cables and hoses in them. That is; to keep water out of the conduits once you've gotten the entire skiff rigged. Not meant to address sealing the pipes except as they act as conduits- with full load of control runs in them.

Glad some of the Forums' many discussions were helpful, please keep us 'posted' on your build.

Cheers,
Kevin Morin
Kenai, AK
kmorin
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