Aluminium Hull Finish

[Pete Makra]

Hey guys, don't know so have to ask. Is there a difference between a smooth plate type hull finish (on some Stessco's) as apposed to the "ribbed" type finish (on most Quintrex's). Does one perform better than the other in getting the boat to plane, cutting through chop & rough water, cruising/top end speed, manourverability etc. Or is it just for asthetics and personal choice on the finish you want. Cheers, Pete

[Chimo]

Hi Pete

Given your quest to buy a boat (your first ?) IMHO you would be well served by a hire or even a cheap tinny purchase as your first boat so you can get your head around some of the issues you are seeking advice on such as ride and differences between pressed and plate aluminium not to mention the attributes of fibreglass as a contrast.

A few K spent and some of your own experience would IMHO assist you greatly to make a wiser, more expensive decision that you may have to enjoy or suffer for quite some time.

Cheers
Chimo

[Noelm]

I guess in a very very broad sense of explanation, boats that are "ribbed" are just pressed thin gauge material, the "ripples" give the metal strength and with a frame work of ribs inside gives them rigidity. A smooth finish is a "plate" construction and uses thicker material to form the hull, perhaps the plate will ride slightly better because it is heavier, but a well designed pressed boat is fine for the casual boater, this is not hard and fast rules, but is a general description of the two build methods.

[bennyboy]

There are 2 kinds of boat construction, pressed and plate. Typically this through referes to the grade of aluminium used.
This is not to be confused however with the current fashion of having a smooth side on a tinnie. With your softer grade of aluminium that most steco's quintrexes, Blue Fin, the list goes on the strongest way to have your aluminium is with pressings or clinker press on the side. To achieve the same structual strength with a smooth side manufactures typically go up to a 3mm side instead of 2mm side.
The advantages of the smooth side is it looks better and people think it's a "plate" boat when it's not.
The advantage of the clinker press is you can get the a stronger boat with lighter materials
Have you ever tried to bend a bit or corrigated roof iron against the curves? Same thing for a ckinker press side of a boat

[Pete Makra]

Hi Pete

Given your quest to buy a boat (your first ?) IMHO you would be well served by a hire or even a cheap tinny purchase as your first boat so you can get your head around some of the issues you are seeking advice on such as ride and differences between pressed and plate aluminium not to mention the attributes of fibreglass as a contrast.

A few K spent and some of your own experience would IMHO assist you greatly to make a wiser, more expensive decision that you may have to enjoy or suffer for quite some time.

Cheers
Chimo

Thanks Chimo, for a first time inexperienced boat enthusiast I agree with you that one should start out small through hire, small boat/tinney purchase and then upgrade but I'm not prepared to spend $'s on a 12' tinney & then have to off-load it to afford an opportunity that may (or may not) come along.

I'm not blowin wind up my own "a....." but I've hired tinnies before, towed skiers, chased illegal fishermen/boat people all over the top end of Aus & been an instructor in boat handling and Coxswains qualifications. Yes, I am looking at my first boat purchase because I now have the time to use it, but I'm not having my first driving lesson!!!;D

I have been out of the "game" for some 10 years so I'm just trying to speak to as many experienced boaties as I can so it gives me the best chance of getting something that will suit out needs. Cheers

[Pete Makra]

There are 2 kinds of boat construction, pressed and plate. Typically this through referes to the grade of aluminium used.
This is not to be confused however with the current fashion of having a smooth side on a tinnie. With your softer grade of aluminium that most steco's quintrexes, Blue Fin, the list goes on the strongest way to have your aluminium is with pressings or clinker press on the side. To achieve the same structual strength with a smooth side manufactures typically go up to a 3mm side instead of 2mm side.
The advantages of the smooth side is it looks better and people think it's a "plate" boat when it's not.
The advantage of the clinker press is you can get the a stronger boat with lighter materials
Have you ever tried to bend a bit or corrigated roof iron against the curves? Same thing for a ckinker press side of a boat

Thanks Bennyboy, you explained it so it made sense. I do like the smooth look I must admit but weight is important I suppose. I'm looking at buying something around the 4.5 to 5 mtr range with a 60 to 75 on the back. Undecided about 2 or 4 stroke as don't really know the difference apart from one has better bottom end grunt and the other better economy. I'm hoping a 60-75 hp will be OK for the size I intend to buy, regardless of being a smooth or pressed hull, cheers.

[Pete Makra]

I guess in a very very broad sense of explanation, boats that are "ribbed" are just pressed thin gauge material, the "ripples" give the metal strength and with a frame work of ribs inside gives them rigidity. A smooth finish is a "plate" construction and uses thicker material to form the hull, perhaps the plate will ride slightly better because it is heavier, but a well designed pressed boat is fine for the casual boater, this is not hard and fast rules, but is a general description of the two build methods.

Thanks Noelm, so If I'm getting the same strength in a pressed hull, I may as well go for the lighter boat. Would you really notice the difference if we're talking about the same size vessel with the same motor, performance wise, cheers.

[indy]

No not right at all you wont be getting the same strength at all most plate boats will use about a 5mm bottom versus pressed about 2mm to 3mm max. I have had pressed boats that will crack along where it has been pressed from constant banging over the years of the boat and they seem to always crack where it has been pressed. Imagine getting a piece of metal and folding it as soon as you fold it it weakens the metal and over time being a lighter gauge than the plate boat it will crack. It all depends on what your going to do with it, if your going out in the bay all the time and a bit of offshore work i would go plate but if your just going up the rivers and occasionly going out in the bay go pressed.

[Daisy Burnett]

I fully agree with Indy. The plate will be stronger and resist abuse a lot better than the pressed aluminium. If you bend metal you weaken it no two ways about it. The more abrupt the bend the weaker the metal structure. Also when talking about on the water performance you dont want your boat too light as it will bounce around like a cork. A good sensible bit of weight in the structure will give you a better ride and more comfortable experience on the water.

Cheers
Daisy

[boatie_72]

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<P><SPAN style="COLOR: black">Just a quick thing, the original question was regarding hull finishing i.e. stessco 3mm smooth&nbsp;sides verses&nbsp;quintrex pressed sides and other brands etc. Benny boy is right in the pressed market the 3mm smooth sides is just a look nothing more and to achieve that look it is better to use 3mm over 1.6 or 2mm, the weight difference will be minimal like 30kg max on top of the weight of the boat. A proper plate boat is&nbsp;built with 5083 plate and&nbsp;have a&nbsp;completely different under floor construction, the pressed side of the&nbsp;industry uses 5251 or 5052 which is a soft material for pressing without cracking. <o:p></o:p></SPAN></P>
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<P>cheers</SPAN></P>

[White Pointer]

G'day,

I'm like you ... or you are like me. Either way it works out the same.

I was a mad keen fisherman in my late teens and early twenties (I'm talking late 1970's) and enjoyed many wasted weekends fishing out of Palm Beach in Sydney and enjoying game fishing competitions to the north and south in a 38' timber cruiser with two 8 litre diesel engines. It was fun, expensive and I didn't care.

Career, marriage and kids put an end to it. I took up golf and played for years and really enjoyed every bit of it.

At Easter 2008 my wife and I visited relatives in Sydney (we now live in Brisbane) and were fortunate to spend the weekend on a 35' power catarmaran. It was like coming home!

We both decided we needed a boat. We didn't want to live on it but it had to be able to sustain us overnight. It had to be a trailer-boat. I wanted a fiberglass boat but was discouraged from this by the conditions of Moreton Bay. Sydney has deep water ports and estuaries. Obstacles are few unless you're stupid. 'Glass is best for ride and stability and good outside. They are heavy and therefore use fuel.

The sand banks and islands in Queensland are a totally different environment. For our needs we decided we needed a heavy plate aluminium hull of at least 6M with lots of power to handle the changeable conditions in this part of the world. It had to be a very good fishing platform.

What do you want to do with yours?

Regards,

White Pointer

[Moonlighter]

Hi Pete

It really depends on what you intend to use the boat for.

Basically, a heavy duty plate boat will handle the open waters and rough weather better and for longer than a pressed boat, and a pressed boat will be lighter and more suited to inshore work and require less hp to drive at a good speed. Plate boat usually more expensive, though not always.

Often plate boat builders are more than happy to customise a boat to suit your needs, whereas most (but by no means all) of the pressed brigade are production models that you can opotion a bit but not change much overall.

There are several grades of marine alloy and the "Plate" boats are usually 5083 grade which is a much harder alloy. This grade is not really suitable for pressing as its too hard. Typical plate boats up to 6m long use 4 or 5mm bottoms and 3 or 4mm sides.

The pressed boats use a more pliable grade of alloy that is suited to having the shape of the strakes pressed into it to give it strength. They are mostly 2.5 or 3mm bottoms and 2 mm sides. The downside is the welding process weakens this softer alloy more than it does to the plate alloy, and pressed boats used in tough conditions are thus prone to "working" the alloy near welds and cracking.

That's why serious open water users tend to go for the plate alloy approach to suit their tougher conditions of use. Stronger plus heavier = better rough water performance (generalised of course).

But lighter duty users in rivers and protected Bays will find pressed boats are fine it treated appropriately.

You'll need to consider what your intended use is and balance costs, - same old equation we all have to do!

Good luck!

ML

[lippa]

shhhhhhhhhhh............

5083 plate sided boats can be clinkered as well!!!!!!!!!!!!!!!!!!!!

[bushbeachboy]

Have a look at the Polycraft too Pete. Very strong, good ride, stable, no corrosion. Have a look on www.polyboatowners.com (http://www.polyboatowners.com) for an idea of what's around.

[Pete Makra]

No not right at all you wont be getting the same strength at all most plate boats will use about a 5mm bottom versus pressed about 2mm to 3mm max. I have had pressed boats that will crack along where it has been pressed from constant banging over the years of the boat and they seem to always crack where it has been pressed. Imagine getting a piece of metal and folding it as soon as you fold it it weakens the metal and over time being a lighter gauge than the plate boat it will crack. It all depends on what your going to do with it, if your going out in the bay all the time and a bit of offshore work i would go plate but if your just going up the rivers and occasionly going out in the bay go pressed.

Thanks indy, I want to go outside occasionally but if my missus likes it the first time I take her out (doubtful) we might go out more often. We will mostly fish in bays and protected waters. I'm slowly warming to the cleaner/smoother hull look that some stessco's have but have plenty of time yet before my purchase, cheers Pete

[Pete Makra]

No not right at all you wont be getting the same strength at all most plate boats will use about a 5mm bottom versus pressed about 2mm to 3mm max. I have had pressed boats that will crack along where it has been pressed from constant banging over the years of the boat and they seem to always crack where it has been pressed. Imagine getting a piece of metal and folding it as soon as you fold it it weakens the metal and over time being a lighter gauge than the plate boat it will crack. It all depends on what your going to do with it, if your going out in the bay all the time and a bit of offshore work i would go plate but if your just going up the rivers and occasionly going out in the bay go pressed.

Thanks indy, I want to go outside occasionally but I'm pretty sure that the first time I take the missus out, will also be her last. She wont like it. We will mostly be bay/protected waters fishin I'd say. We found a great little place down the coast at Sussex Inlet NSW that we like and a mate took us out a few times in the inlet, but I tell you what, we pounded through the chop/swell a few times when the wind got up. I want the boat I buy to last me for some time so need to choose carefully, cheers Pete

[Pete Makra]

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<P><SPAN style="COLOR: black">Just a quick thing, the original question was regarding hull finishing i.e. stessco 3mm smooth&nbsp;sides verses&nbsp;quintrex pressed sides and other brands etc. Benny boy is right in the pressed market the 3mm smooth sides is just a look nothing more and to achieve that look it is better to use 3mm over 1.6 or 2mm, the weight difference will be minimal like 30kg max on top of the weight of the boat. A proper plate boat is&nbsp;built with 5083 plate and&nbsp;have a&nbsp;completely different under floor construction, the pressed side of the&nbsp;industry uses 5251 or 5052 which is a soft material for pressing without cracking. <o:p></o:p></SPAN></P>
<P>&nbsp;</P>
<P>cheers</SPAN></P>

Thanks boatie 72, so does that mean there is no difference between say a stessco with 3mm smooth sides and a quintrex with 3mm pressed sides:-/ , cheers Pete

[Axl]

Thanks Bennyboy, you explained it so it made sense. I do like the smooth look I must admit but weight is important I suppose. I'm looking at buying something around the 4.5 to 5 mtr range with a 60 to 75 on the back. Undecided about 2 or 4 stroke as don't really know the difference apart from one has better bottom end grunt and the other better economy. I'm hoping a 60-75 hp will be OK for the size I intend to buy, regardless of being a smooth or pressed hull, cheers.

Hi mate I am not sure where you are based but have a look at this link I brought myself one of these for xmas last year and so far I have 10 hours on the motor 60hp 2stroke Mercury for the price i tnink that they are a very nice rig. http://www.cunninghamsmarine.com.au/brooker_500discovery_cc.shtml

[White Pointer]

Thanks indy, I want to go outside occasionally but I'm pretty sure that the first time I take the missus out, will also be her last. She wont like it. We will mostly be bay/protected waters fishin I'd say. We found a great little place down the coast at Sussex Inlet NSW that we like and a mate took us out a few times in the inlet, but I tell you what, we pounded through the chop/swell a few times when the wind got up. I want the boat I buy to last me for some time so need to choose carefully, cheers Pete

G'day,

I've read through all the posts and thought there was some pretty good advice until you made this post.

If you are planning to go outside from Sussex Inlet you need a very sea-worthy boat. This area can produce surf at sea where currents meet and weather changes can turn the sea into a washing machine. Weather forecasts are well and good but this area seems to manifest sudden changes in the intensity of southerlys and is renowned for producing storms at sea that lash the south coast area of Sydney's suburbs.

There is no way that I would go outside from Sussex Inlet in anything less that 6M with 175HP to 200HP on the back. While it may just be the occasional trip outside it only takes one of these when it all turns to shit to kill you in a little boat.

I would broaden your search for late model fiberglass boats. The Sydney area has deep water ports and they don't encounter the conditions that make aluminium plate the boat of choice for many up here in Queensland.

Regards,

White Pointer

[Pete Makra]

G'day,

I've read through all the posts and thought there was some pretty good advice until you made this post.

If you are planning to go outside from Sussex Inlet you need a very sea-worthy boat. This area can produce surf at sea where currents meet and weather changes can turn the sea into a washing machine. Weather forecasts are well and good but this area seems to manifest sudden changes in the intensity of southerlys and is renowned for producing storms at sea that lash the south coast area of Sydney's suburbs.

There is no way that I would go outside from Sussex Inlet in anything less that 6M with 175HP to 200HP on the back. While it may just be the occasional trip outside it only takes one of these when it all turns to shit to kill you in a little boat.

I would broaden your search for late model fiberglass boats. The Sydney area has deep water ports and they don't encounter the conditions that make aluminium plate the boat of choice for many up here in Queensland.

Regards,

White Pointer

Thanks White Pointer, sorry haven't replied but been away. We go to Sussex quite often and haven't come across anything as bad as you're describing yet but I agree things can change very quickly, and not just in this area. By outside I mean a couple of kls offshore. You wont catch me much further out than this in any small tinny and I would never be out of sight of land. Safety first and I don't take risks, cheers Pete

[BOMBIE]

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<P><SPAN style="COLOR: black">Just a quick thing, the original question was regarding hull finishing i.e. stessco 3mm smooth&nbsp;sides verses&nbsp;quintrex pressed sides and other brands etc. Benny boy is right in the pressed market the 3mm smooth sides is just a look nothing more and to achieve that look it is better to use 3mm over 1.6 or 2mm, the weight difference will be minimal like 30kg max on top of the weight of the boat. A proper plate boat is&nbsp;built with 5083 plate and&nbsp;have a&nbsp;completely different under floor construction, the pressed side of the&nbsp;industry uses 5251 or 5052 which is a soft material for pressing without cracking. <o:p></o:p></SPAN></P>
<P>&nbsp;</P>
<P>cheers</SPAN></P>
Pete ,don't be confused 5021/52 is pressed/sheet alloy with is about 96 mpa (impact resistance) where as 5083 PLATE is 285 mpa (ir) weather it's 1.6,2,3,or whatever mm ribbed or not;) , which is like comparing sheet metal to hi-tensile and stressco IS NOT plate up to 5.3 mtrs unless they state it is 5083?. They state pressed in there ads ??? I would ask an reliable authorityon the quality of it before I'd purchased one just to be sure ..this I know :( ..PS still hate my boat ?:'( >:(