What is a true Plate Boat?

[troy]

This has probably been done to death but i have found searching this Forum on what is a plate boat opinions very.
Eg Formosa Boats call there boats plate but have seen where some members differ.
So what brands are without doubt genuine plate boats.
Troy

[FishHunter]

Afaik a plate boat is made with sheets of ally plate welded together. The others are pressed hulls from thinner ally. Quintrex etc. If there is ribbing or fancy curves then its pressed and not a Plate boat

Sent from my X10i using Tapatalk

[Muddy Toes]

So is a Trailcraft is not a real plate boat then?

[krazyfisher]

a true plate boat is made from a grade of aluminium that is call "plate" rather than "sheet", it is about strength and structural properties. at what point you call it plate, well that is another dicussion. you can press "plate" but mostly it does not like it and the idea is the pressing adds strength that is not needed with "plate".

not a perfect answer but hope it helps

[NAGG]

I think you'll find that it has nothing to do with the form that the Aluminium sheet is used - you can press a 3 or 4mm sheet into shape & build it as a plate alloy boat.
It is all based on the stringers , bulkheads , keel & sides etc and how they are welded ....... this creates the strength when welded all into place ( including the floor).

Some boats look like plate ....... but are not true plate build - The Seajay Topender I am buying is a prime example (3mm all round) .... but does not look like a Quinny type of pressed boat. ....... yet it is a pressed boat

Chris

[troy]

I am just using Formosa Boats for an eg during my search members have said they are not a plate boat.
Formosa claims they are so who is right.
I tend to go along with Nagg.
Troy

[hakuna]

Troy,

Look at it this way, if cop a green wave over the top and you need to put a bilge pump on, it is not a true plate boat, a plate boat has a fully welded sealed hull normally full of flotation with scuppers, water goes out the back and gone. If full of water, the good plates will have the floor level should be at or above the water line, which means motor above water and still running.
As for Formosa, they use a plate floor tack welded to the sides and filled with sillastic, and use a bilge at back to pick up all the water as they leak like a sive, not welded or sealed hull, NOT a plate boat. They use an inteleget way of advertising without exactly saying it is a true plate boat. (my brother has one). Not saying they are a bad boat, but you get what you pay for.
Your talking about Goldstar, riptide,seastorm, Origin, Noble ,seajay etc

cheers

[FishHunter]

I think you'll find that it has nothing to do with the form that the Aluminium sheet is used - you can press a 3 or 4mm sheet into shape & build it as a plate alloy boat.
It is all based on the stringers , bulkheads , keel & sides etc and how they are welded ....... this creates the strength when welded all into place ( including the floor).

Some boats look like plate ....... but are not true plate build - The Seajay Topender I am buying is a prime example (3mm all round) .... but does not look like a Quinny type of pressed boat.

Chris

So if I use some secret squirell way to build a boat out of 1mm sheet then its a plate boat?

[FishHunter]

Troy,

Look at it this way, if cop a green wave over the top and you need to put a bilge pump on, it is not a true plate boat, a plate boat has a fully welded sealed hull normally full of flotation with scuppers, water goes out the back and gone. If full of water, the good plates will have the floor level should be at or above the water line, which means motor above water and still running.
As for Formosa, they use a plate floor tack welded to the sides and filled with sillastic, and use a bilge at back to pick up all the water as they leak like a sive, not welded or sealed hull, NOT a plate boat. They use an inteleget way of advertising without exactly saying it is a true plate boat. (my brother has one). Not saying they are a bad boat, but you get what you pay for.
Your talking about Goldstar, riptide,seastorm, Origin, Noble ,seajay etc

cheers

So if I take the bilge pump off my glass boat as it doesnt leak then its a plate boat?

[The Woo]

Troy,

Look at it this way, if cop a green wave over the top and you need to put a bilge pump on, it is not a true plate boat, a plate boat has a fully welded sealed hull normally full of flotation with scuppers, water goes out the back and gone. If full of water, the good plates will have the floor level should be at or above the water line, which means motor above water and still running.


^^^ That's really just a self draining deck ;)

A "Plate Boat" is a "substantially" built boat. ie, an aluminium boat that is made of substantial aluminium plate that is not easy to press into a shape. Rather, to get the shape in the hull, the plate is rolled into shape, and placed over the inner aluminium frame work, then welded to it.
Typical bottom thickness for an up to 8 metre boat would be 5mm, with sides and superstructure 3mm.
The floor and the framing between the floor and hull bottom are integral to the boat's strength, unlike most pressed boats that the floor is completely independant of the hull bottom and not relied on for structural strength.

That's my opinion.

*** I wonder why it took so long for dodgy pressed boat builders to start advertising their boats as "plate". The uninitiated are easily confused. Heck, a mate of mine bought a 4.5m Bluefin I think it is, he's convinced its a platey.

[tunaticer]

You are right Troy, this has been done to death a hundred times over.
If you like the boat, buy it regardless of how many say it is a true plate boat or not.
What real difference does it make how it is designated??

Pressed hulls can be pressed from plate material as well, would that remove its plate categorization??

To be perfectly honest, there are good pressed hulls and good plate hulls on the market that are duly suitable for their intended level of usage. Step outside of those boundaries in both plate and pressed hulls and you will find problems somewhere.

I suspect that sooner or later some nutcase will offer up a 10mm thick "plate hull" to be absolute in its categorization yet will this boat last forever?? Never will it last that long and most likely will suffer from being over built and cracking will occur.

Select the boat that most appeals to you and buy it, use it and enjoy it.

The categorizing it into plate boat is purely wank factor when you use any boat within its design parameters.

[NAGG]

So if I use some secret squirell way to build a boat out of 1mm sheet then its a plate boat?

Seriously ..... 1mm plate ? - maybe foil:D

What you can do is build a boat with 4mm sheet ........ but without building the internal box type bulkheads which is welded to the stringers , bottom , sides & floor ........ it wont be a plate boat

Chris

[FishHunter]

Seriously ..... 1mm plate ? - maybe foil:D

What you can do is build a boat with 4mm sheet ........ but without building the internal box type bulkheads which is welded to the stringers , bottom , sides & floor ........ it wont be a plate boat

Chris

No because its built with sheet

[PinHead]

troy..if you like the boat then buy it..forget what anyone on here says about it..sheet ? plate? it is al lthe same..just some more Al...if the boat suits your needs..good for you.

[NAGG]

No because its built with sheet

It;s all sheet ...... If someone wanted too - they could probably build a plate boat using 1mm sheet ...... though it does defeat the purpose

[NAGG]

troy..if you like the boat then buy it..forget what anyone on here says about it..sheet ? plate? it is al lthe same..just some more Al...if the boat suits your needs..good for you.

yes ..... more aluminium - but not necessarily in the outer skin

Chris

[troy]

troy..if you like the boat then buy it..forget what anyone on here says about it..sheet ? plate? it is al lthe same..just some more Al...if the boat suits your needs..good for you.

Mate this not about me buying any boat as it is confusion about what is a true plate boat.
In hours of going through the Forums even though you pick up great advise i have found that Forums can turn you off a boat that you think is a good option then you see members that will knock that boat.
It is really like Holden v Falcon.
I just wanted to know from someone who is willing to be unbiased on what is a true plate boat and i do not think i will get that.
Troy

[Mr__Bean]

Half way down the second page and we still don't have anything definative.

So, it is a loosely used term without meaning that is at times used to talk up the build status of smaller aluminium boats.

Darren

[NAGG]

Mate this not about me buying any boat as it is confusion about what is a true plate boat.
In hours of going through the Forums even though you pick up great advise i have found that Forums can turn you off a boat that you think is a good option then you see members that will knock that boat.
It is really like Holden v Falcon.
I just wanted to know from someone who is willing to be unbiased on what is a true plate boat and i do not think i will get that.
Troy

troy ..... speak your mind mate !

I went to two boat manufacturers to have a look ...... & asked the question - both were open enough to tell me & show me ......
One built both a pressed design & a plate .......... It's chalk and cheese - now .... when you see the plate design - its made up of fully welded boxes that are welded to the floor , hull & bottom ....... it would not matter one iota if the skin was 5mm bbq plate or 3mm that was pressed to make a certain form = the key is what is between the sides , floor & bottom .

A full plate design is more rigid - handles a bigger motor - has a self draining floor (via scuppers) = weighs more giving a better ride (often) ...... Is a stronger boat that carries more weight ,
It's a better choice for a bigger boat , that fish further offshore & carry greater weights. A 5.5M offshore boat would be best using a full plate design ....... while the 5m estuary boat would be better served by the lighter pressed design

Chris

Chris

[The Woo]

I just wanted to know from someone who is willing to be unbiased on what is a true plate boat and i do not think i will get that.
Troy

I was being as unbiased as possible.... I don't like any tin boats :)
(with one exception.... it's the tin boat that picks me up out of the water if my own boat has sunk) :)

[johncar]

Well I just refer to them all as "Tinnies" including mine regardless which saves all the hype. I think that there is in fact an industry cut off point where Sheet finishes and Plate starts which I think may be 1/4" which leaves many so called "Plate boats" perhaps falsely named as only a few have 1/4" material in their full construction although some have 1/4" bottom sheets. But at the end of the day mine is 5mm and 4mm sheets and I don't care either way as it's a great boat by any "name".
There are however two distinct forms of construction between a typical pressed hull and a flat sheet hull and either one seems to perform well. I have owned both and been happy with both and either one has their advantages.
Maybe we need new names to differentiate like "Independan"t hull (Pressed) and "Integrated" Hull (sheet or plate) because it's more about the design than the material used.

[Matt76]

I think the answer is quite subjective and the answer will always differ from person to person. I judge a 'plate' boat by its structure, or lack thereof. The only real structure a true plate boat has is some ribbing under the floor. The rest of the strength is in the sheets (or plates haha), the gunnel extrusions and a fully welded floor. A lot of the pressed plate lookalikes still have hat section running up the sides to give them strength. I also have a 3.1m tinny which is obviously very light sheet and needs a frame structure to give it strength.

[Tangles]

its a boat that will run over a bommy with only a few scratches and still float!

[chris69]

In boat building when a patten is cut out of a sheet of what ever material this is called a plate,side plate, chine plate , bottom plate,even a oil tanker is a plate build lol,pressed aliminium molded and cut from a patten plate thats how i see it.

[Axl]

I just wanted to know from someone who is willing to be unbiased on what is a true plate boat and i do not think i will get that.
Troy

I dont see that anyone has been biased towards anything in this thread and I think the guys have given you some pretty good advice around the question you have asked.

As far as an answer to your quetion goes (IMO) it certainly comes down to peoples opinion but at the end of the day if you can afford a Formosa then go for it, if you can afford a Goldstar, Origin, Noble, Pelagic, Bar Crusher or Bluewater to name a but few then go for one of them. To me they are all "plate alloy" boats and they all have different atributes hence the difference in prices.

I am currently looking at "plate alloy" boats myself and for me it looks like ill be going with the Formosa as they suit my budget. With 4mm 5083 alloy sides and bottom it will be heavier than my current rig, should ride better and be some what stronger which is what I am after. They are painted and the Tomahawk range comes with some nice appointments (IMO). As for the sikaflex around the floor again you get what you pay for.

Its a big decision you are making and I can understand your apprehension as there is a rather large some of money involved and there is so much out there today to choose from. Getting it right rather than ending up with something that doesnt suit is what we all wont when doing some thing like this but I dont think your comments above were very fair on the guys that have replied to your question (IMO).

[troy]

I dont see that anyone has been biased towards anything in this thread and I think the guys have given you some pretty good advice around the question you have asked.

As far as an answer to your quetion goes (IMO) it certainly comes down to peoples opinion but at the end of the day if you can afford a Formosa then go for it, if you can afford a Goldstar, Origin, Noble, Pelagic, Bar Crusher or Bluewater to name a but few then go for one of them. To me they are all "plate alloy" boats and they all have different atributes hence the difference in prices.

I am currently looking at "plate alloy" boats myself and for me it looks like ill be going with the Formosa as they suit my budget. With 4mm 5083 alloy sides and bottom it will be heavier than my current rig, should ride better and be some what stronger which is what I am after. They are painted and the Tomahawk range comes with some nice appointments (IMO). As for the sikaflex around the floor again you get what you pay for.

Its a big decision you are making and I can understand your apprehension as there is a rather large some of money involved and there is so much out there today to choose from. Getting it right rather than ending up with something that doesnt suit is what we all wont when doing some thing like this but I dont think your comments above were very fair on the guys that have replied to your question (IMO).
Mate my comments were not meaning anything towards members.
Maybe i word things wrong.
I just wanted a unbiased opinion and did not think that i would get it because they all have different thoughts on this.
So i was not being unfair to anyone who posted.
Troy

[troy]

troy ..... speak your mind mate !

I went to two boat manufacturers to have a look ...... & asked the question - both were open enough to tell me & show me ......
One built both a pressed design & a plate .......... It's chalk and cheese - now .... when you see the plate design - its made up of fully welded boxes that are welded to the floor , hull & bottom ....... it would not matter one iota if the skin was 5mm bbq plate or 3mm that was pressed to make a certain form = the key is what is between the sides , floor & bottom .

A full plate design is more rigid - handles a bigger motor - has a self draining floor (via scuppers) = weighs more giving a better ride (often) ...... Is a stronger boat that carries more weight ,
It's a better choice for a bigger boat , that fish further offshore & carry greater weights. A 5.5M offshore boat would be best using a full plate design ....... while the 5m estuary boat would be better served by the lighter pressed design

Chris

Chris
Nagg, it not about me speaking my mind as i cannot say what a true plate boat is because if i knew i would not have stared this thread.
I agree with what you have said.
But opinions still vary and probably always will as it is very confusing but i respect members opinions.
Troy

[Smithy]

I reckon it comes down to the underfloor structure. If it has full length stringers and a lattice work of bearers it is a true platey, if they are ribs that are folded and some C type channel or similar they are a tinny. I had a Mclay with clinkered sides but they were 5mm and it had a keel protector on the bottom and I had 10mm of thickness down there. I regarded it a true platey but many thought of it as a tinny, purely because it had clinkered sides. Hakuna is off the mark. Trailcrafts satisfy his criteria which is just a self draining deck. I regard them as WA built Quintrexs pretty much. My Stabi and Mclay both had deck water drain into a bilge to be pumped out. Now you can't say they weren't true plateys.

[Horse]

I had an old 16' Abalone with a full self draining deck. It was a pressed tinny. As others have said it all comes down to the hull support mechanisms in my opinion. pressed hulls use the shape to provide integrity and strength while the plate builder uses manufactured box sections

[gofishin]

From an old post
...The difference between true 'pressed' and 'plate' construction techniques isnot in the look of the sides etc, but how they are built. Pressed boats and hybrids are built hull-shell first, using extrusions for seam joints, then theinternal structure is added last. They are 'normally' a lot more lighter duty than plate boats. True plate boats are built like a traditional timber boat - a rigid frame structure comprising a matrix of welded stringers, bearers,x-members, b/heads etc is built on a jig first, and the hull sheeting is added last.

Just because a boat has flat sides doesn't mean it is a plate boat either. There are many 'hybrids' out there - combining both construction techniques in some way or another. Trailcraft are one of them. There are also many pressed boats with flat sides (with maybe one chine & gunnel pressing to stop rippling) that are sold as plate boats, but they aren't.

cheers

The frame matrix in a plate boat is usually more heavier duty (more members) and is made from heavier material. Whether it is plate or pressed/hybrid is also not determined by the thickness of the aluminium. A true plate can & does have 4mm material, and possibly even 3 in the sides but can still be a plate boat – it depends on it size and intended purpose (the F&B ‘Red Ink’ probably was 4 & 3 for those that remember, as it was quite small, and a proper plate boat from memory).

Some, but probably not all, also use different grades of alloy, and with different hardness. 5083 H32 is probably most common with the plate boys. It is quite hard, meaning you can’t bend/press it too much else it will crack/peel. 5 and 6mm of this can be pressed with typical side clinker dies, but try it with a typical bottom pressing (planing strake shape) and the acute fold will peel apart and crack along the bend/fold. 5052 and 5252 is probably more common with the pressed & pressed-plate/hybrid manufacturers, and for stretch-forming 5052 & 5252 H22 was typical and probably still is.
In the end, it comes down to what best suits the intended purpose and what you can afford - or want. Plate boats take longer/more man-hours to build and hence are more expensive.
cheers

[Moonlighter]

Gofishin has pretty well nailed it.

My simplified version is this:

Pressed boats, built from more pliable grades of marine alloy, gain a significant proportion of their strength and rigidity from the pressings in the alloy. The more pliable grade alloy that has to be used in their construction to allow the pressings is more likely to suffer from "working" - ie the flexing of the hull, which eventually weakens the alloy, especially around welds. To a fair extent, the internal structure is there to keep the sides of the boat apart, and this internal structure is typically lighter weight in its design.

The upside of pressed boats is that they are lighter, the downside is that they dont have the strength/rigidity and therefore cant take the work that a plate hull can over an extended time frame.

Plate boats, built from the harder grades of alloy such as 5083, do not rely much on pressing the alloy sheets for their strength, rather, it comes from a combination of the stronger structural alloy used plus the structure both under the floor and above the floorand in the transoms, coamings and cabin. Upside = strength and durability, downside = heavier weight because of the more extensive structureal elements in the boat.

The other issues such as wether the deck is self-draining or not are really phurphys in the context of the argument about whether a boat is a "plate boat or not.

The only one of these "side" issues that I think would be of some relevance is the presence or otherwise of a welded-in alloy floor, because that can be an indicator of the structural design of the boat, but a wooden floor wouldnt necessarily rule out the boat being a "Plate" boat. Lots of the earlier Sportfish plate boats had ply floors in them.

So, how do you tell a "plate boat" apart? Id ask the builder who was saying that his is a plate boat the following 2 questions, and you need to get the right answers to both of these questions. not just one, to be satisfied you are looking at a plate boat, IMO:

1. What grade of alloy is used in the construction of the hull, transom and other structural components? The correct answer should be 5083, if it's not then ask more questions and find out the actual grade they use.

2. Can I see the "under floor" design please. It better have solid (ie at least 4mm in smaller versions and 6mm or more in larger ones) full width welded in frames and /or substatial longitudinal stringers, both of which are welded to the hull and have the floor welded (preferably) to them.

Cheers

ML

[wirlybird]

You have it all wrong guys here are two versions that are the best way to show a plate boat.;D

I like the paper plate boat

[Black_Rat]

This is a true one ;D

[wirlybird]

This is a true one ;D

Damn strait what are you guys on about ;)

[NAGG]

It does pay to understand the difference .......... & to say it's not that important is wrong!!!! -
Before I was actually shown there were plenty of boats that I thought were plate but were actually a good pressed design using thicker side sheets.
I now understand why 2 fairly similar looking boats can be so different in price ..... ie Seajay topender vs Seajay plate extreme side console ....... Thousands of dollars more for a boat that is just 100mm longer than the one I ordered.

yes it's all about what suits your needs best & what you can afford ......... just dont let someone tell you a boat is plate when it may not be.

Chris

[troy]

Gofishin has pretty well nailed it.

My simplified version is this:

Pressed boats, built from more pliable grades of marine alloy, gain a significant proportion of their strength and rigidity from the pressings in the alloy. The more pliable grade alloy that has to be used in their construction to allow the pressings is more likely to suffer from "working" - ie the flexing of the hull, which eventually weakens the alloy, especially around welds. To a fair extent, the internal structure is there to keep the sides of the boat apart, and this internal structure is typically lighter weight in its design.

The upside of pressed boats is that they are lighter, the downside is that they dont have the strength/rigidity and therefore cant take the work that a plate hull can over an extended time frame.

Plate boats, built from the harder grades of alloy such as 5083, do not rely much on pressing the alloy sheets for their strength, rather, it comes from a combination of the stronger structural alloy used plus the structure both under the floor and above the floorand in the transoms, coamings and cabin. Upside = strength and durability, downside = heavier weight because of the more extensive structureal elements in the boat.

The other issues such as wether the deck is self-draining or not are really phurphys in the context of the argument about whether a boat is a "plate boat or not.

The only one of these "side" issues that I think would be of some relevance is the presence or otherwise of a welded-in alloy floor, because that can be an indicator of the structural design of the boat, but a wooden floor wouldnt necessarily rule out the boat being a "Plate" boat. Lots of the earlier Sportfish plate boats had ply floors in them.

So, how do you tell a "plate boat" apart? Id ask the builder who was saying that his is a plate boat the following 2 questions, and you need to get the right answers to both of these questions. not just one, to be satisfied you are looking at a plate boat, IMO:

1. What grade of alloy is used in the construction of the hull, transom and other structural components? The correct answer should be 5083, if it's not then ask more questions and find out the actual grade they use.

2. Can I see the "under floor" design please. It better have solid (ie at least 4mm in smaller versions and 6mm or more in larger ones) full width welded in frames and /or substatial longitudinal stringers, both of which are welded to the hull and have the floor welded (preferably) to them.

Cheers

ML
Good reponce so would are your thoughts on a not fully welded floor but just tacked as mentioned in other posts.
Troy

[pipifin]

it's all a crock of sheet

[troy]

it's all a crock of sheet

Care to explain

[Stuart]

Those sort of questiones should be directed at a naval architect and not on forums where every known myth will be told as fact. It happens way to often mate where a simple question is asked and then all of a sudden you have everyone saying this and that and all based on what they think or what they have been told by a mate that knows a welder that use to build boats. I built my own plate alloy using 5083 H116 DNV. To say I learnt heaps would be an understatement. Plenty of myths I had heard where blown out of the water so to speak. Do some research but at the end of the day buy what suites your needs and tast.

Stu

[Moonlighter]

Good reponce so would are your thoughts on a not fully welded floor but just tacked as mentioned in other posts.
Troy

I would think we are now entering the issue of quality into the equation when you see a tacked in floor. Boat might still be a plate boat, but maybe not as good as it could be, possibly cutting corners.

ML

[Axl]

This subject certainly brings up some good discusion. After reading what Smithy and Moonlighter have said about under floor construction I had a look around the net and found a couple of pics.

Sea jay 77484 you can see the longitudinal stringers in the way of plate that has been cut to suit the bulkheads also plate that has been cut to suit both welded to the bottom plates and I am assuming that the webbing will be next.

Origin 77486 Obvious to see here very strong under floor stucture with box type sections welded to the bottom plates also much more expensive.

Formosa 77483 again you can see the longitudinal stringers (Formosa use alloy RHS instead of plate ive seen this first hand) and the bulkheads again both welded to the bottom plates and in this pic you can see some of the webbing going in.

I have another question though the pic of the Formosa build shows what I think are called ribs going from the bottom plates up the side plates.

Looking around the net at finised/unfinished boats from other brands I have only seen this (the ribs) used in there boats and I am wondering why Formosa do this but the other brands dont. Does anyone know?

[Axl]

Mate my comments were not meaning anything towards members.
Maybe i word things wrong.
I just wanted a unbiased opinion and did not think that i would get it because they all have different thoughts on this.
So i was not being unfair to anyone who posted.
Troy

Fair enough Troy maybe it was the way it was worded, or the way I read it, all is good;).

[Fed]

I'm pretty sure the manufacturers & suppliers of alloy call anything above 4.0mm plate and anything 4.0mm and below is called sheet.

I saw a thread rage for weeks about this a couple of years ago, I think Trailcraft was the target then.

[troy]

There is a Dealership that says they are the plate boat Specialist yet this brand of boat a few have said they are not a plate boat.
Troy

[Moonlighter]

Axl

If you look at the Formosa more. Carefully and compare to the others IMO you can see it's more like a beefed up version of a pressed boats underfloor structure. Which is consistent with their approach of using ribs up the sides as well.

Compare to the following shot of the underfloor structure on my Surtees and you'll see the differences. Stringers and cross frames are solid and go from hull to deck, and it's all fully welded. And this on a 5.5m hull.

http://i729.photobucket.com/albums/ww298/Moonlighters_album/Surtees/DSCN0069.jpg

Cheers

ML

[johncar]

There is a Dealership that says they are the plate boat Specialist yet this brand of boat a few have said they are not a plate boat.
Troy

I think it is clear that the term is used fairly loosely and it is just better to do you research on what style of construction best suits your budget and needs and go with it.
Every thing built by man on the planet has extremes in design and blurred with everything in between.

Would it be fair to say that recreational Alluminium boats started their life as a lightweight and cheaper alternative to much heavier and more expensive GRP and timber or steel.
Their upside was economy and adaptability, customisation etc. Downside is rougher and often wetter ride. So came the Platey with it's heavier sheets and hull designs to rival the best GRP boats so gone is the economy factor but retained is the customisation and ability to personalise your boat. As a natural course there are many hybrids out there that try to retain some of that economy but add some better sea handling and ride characteristics so we also have everything in between a fully welded heavy plate/sheet boat to the lightweight pressed sheet tinnie.
With this in mind it can be a bit blurred and possibly pointless to try and catagorise all the hybrids one way or the other as they have some features of either design in them. Just look at the boats in your budget of purchasing and running costs and consider what they are offering in regards to your needs and don't get to worried about popularist views and the knockers of either design.

But to answer your question if it is important to you, a true plate boat in IMHO is one that is fully welded and constructed out of appropriate grade Ally sheet of at least 4mm bottom sides and 3mm top sides being needed to provide a final build weight and design that rival similar sized GRP boats.

[PB]

it is true the term plate boat is used very loosely these day, but a few of you have it correct the term comes from boat builders using a 5083 grade aluminium witch is classed as plate the minimum thickness in this series is 3mm and can go right up to 100mm in thickness. 5083 is a high strength alloy that is widely used in the transport and marine industry where strength and rigidity is required and it also has a very high resistance to corrosion. it also has its down side it can be very hard to bend if you don't have the right equipment and know how. 5251/5052 is classed as sheet alloy and is only available is thickness from 1mm up to 3mm. it does not have the tensile strength of 5083 making it much easier to bend and form into shape, this grade of sheet is widely used on pressed hull boats for this reason.

So the term plate boat simply comes from the grade of aluminum being used, 5083 is PLATE & 5251/5052 are classed as SHEET its as simple as that.

There are a few cases where some plate boats use 4mm bottoms & 3mm sides and are some times not called a true plate boat, 9 time out of 10 these will be a production built boat and they could use a combination of both 5083 for the bottom (4mm) and 5052 for the sides as the majority of them have some sort of fold line in the side.

The major difference is the price tag, the production built boats will always be cheaper even if they use 5083 plate due to the way they are cut and assembled. where as the likes of our selves and all the other custom boat builders we normally build 1-2 boats at a time cutting, folding and welding each part individually.

[Axl]

Axl

If you look at the Formosa more. Carefully and compare to the others IMO you can see it's more like a beefed up version of a pressed boats underfloor structure. Which is consistent with their approach of using ribs up the sides as well.

Compare to the following shot of the underfloor structure on my Surtees and you'll see the differences. Stringers and cross frames are solid and go from hull to deck, and it's all fully welded. And this on a 5.5m hull.

http://i729.photobucket.com/albums/ww298/Moonlighters_album/Surtees/DSCN0069.jpg

Cheers

ML

Thanks ML I think the pic I posted of the Formosa build is an old one posibly there MK2 hull (they are making a MK3 hull now) I was at there workshop last year and they had a 5.2 in construction and it looked very similar to the pic you have posted of your rig.


it is true the term plate boat is used very loosely these day, but a few of you have it correct the term comes from boat builders using a 5083 grade aluminium witch is classed as plate the minimum thickness in this series is 3mm and can go right up to 100mm in thickness. 5083 is a high strength alloy that is widely used in the transport and marine industry where strength and rigidity is required and it also has a very high resistance to corrosion. it also has its down side it can be very hard to bend if you don't have the right equipment and know how. 5251/5052 is classed as sheet alloy and is only available is thickness from 1mm up to 3mm. it does not have the tensile strength of 5083 making it much easier to bend and form into shape, this grade of sheet is widely used on pressed hull boats for this reason.

So the term plate boat simply comes from the grade of aluminum being used, 5083 is PLATE & 5251/5052 are classed as SHEET its as simple as that.

There are a few cases where some plate boats use 4mm bottoms & 3mm sides and are some times not called a true plate boat, 9 time out of 10 these will be a production built boat and they could use a combination of both 5083 for the bottom (4mm) and 5052 for the sides as the majority of them have some sort of fold line in the side.

The major difference is the price tag, the production built boats will always be cheaper even if they use 5083 plate due to the way they are cut and assembled. where as the likes of our selves and all the other custom boat builders we normally build 1-2 boats at a time cutting, folding and welding each part individually.

Intersting to here your thoughts PB thanks for your comments, obviously from some one who is in the know.

Any way hopefully all of this has helped you out with your descision Troy, it certainly has helped me out with mine. Thanks to all how have supplied info/comments and thanks to you Troy for starting a thread that has given me more info than I ever thought I would get on this subject;).