Wood, Aluminum, GRP or Steel ?

[Mambo42]

I am searching for a slightly larger boat and am running into several options. At the moment I have a Defever 49, which is made of GRP. I understand GRP, so there are little to few surprises there.
During my search I found a steel yacht, built in 1990, an aluminum yacht, built in 2001 and a complete wooden yacht, built in 1989.
They all do look well maintained, 1 of them (the wooden one) had a complete refit (stripped to the bone) in 2019, the steel one received an extension and the aluminum one is the youngest one, but I basically have no idea what the pros and cons are of each material.
I have seen videos about the problems with steel yachts, meaning that you basically keep working 24/7 to keep the corrosion out. I know the channel of the 70' aluminum yacht in Alaska, where they removed the paint, since that is apparently better for the hull. The boat I am looking at is completely painted, don't think it will be easy to remove the paint. And the wooden yacht ? I understand that if wood is kept in the water in can last forever, but putting it on the dry for, let's say, the winter, may already lead to problems such as the wood drying out and causing leakages.

So am curious to everyones opinion, are steel, aluminum and wood an option or will I be better off by sticking with GRP and searching in that area ? What are the most common issues I would encounter with any one of these options ?
One last option I am thinking about (although would be a last resort option) is to extend my current boat with about 10'.

 

[psneeld]

Each and every material has strengths and weaknesses. The worst weakness is a myth about the material.

Depending on the construction and overall maintenance, wooden boats can be taken out of the water for the winter and properly maintained/refloated, suffer no great deterioration. True some might do better water stored, but that can depend also. Most all the wooden boats I started on back in the 60's were hauled for the winter and were decades old and lasted well beyond my years on them.

Steel boats often corrode from the inside out because of inaccessible areas or just plain neglect. To do the proper maintenance, the ability to inspect and maintain needs to be relatively easy. It is super easy to repair, even in the far corners of the world I have been told.

Aluminum can resist plain old salt water corrosion fairly well, but stray electrical can be devastating in a short amount of time.

Any material needs a lot of study to make sure you know what you are getting into, and then the boat and use will fall better into place.

I think most fiberglass boats win the race as many are not world cruisers and glass seems to be the most forgiving for lack of maintenance and ignorance if it's pitfalls.

 

[Mambo42]

Is there any way to tackle the corrosion from within in a steel boat or is it hoping that the yard that built the boat has done a decent job in giving the steel an anti corrosion treatment ?

The wooden boat did have some wood rot prior to the refit (see picture), but the refit was so extensive (they did sent me all the pictures) that I think it was taking care off at that time. However, that was in 2019 and now we are in 2026, so what has happened in the mean time and how will I find it ?

As for the aluminum one, if I would be a port and a boat closeby (or the port or anchorage itself) would have stray currents, would that affect the boat ?

 

[Mac2]

How do you plan to use the boat? I wouldn’t even consider wood. Aluminum is great maintenance wise, but they are usually built for speed and they have huge engines. Maybe that’s what you want. The aluminum one in Alaska has the stern extension. Like most extensions, the props and rudders are in the same location, which will affect the steering performance. Steel HAS to be well insulated, or like the above pst stated, they will rust from the inside out (due to condensation). I have owned my steel boat for 7 years. Without a doubt, my steel boat is exponentially easier to care for than my previous 1985 fiberglass boat (blister job, stern delamination, window leaks etc). I still like fiberglass because you can repair everything, but I would pay attention to what was used for the core material (preferably waterproof). Painted aluminum-ugh! I just painted/repaired my aluminum flybridge (an add on). Paint doesn’t like to stick to aluminum, so it tends to bubble up when it starts to fail. The prep/etch is key. I understand why that aluminum boat got rid of the paint when it started to fail. Unless you’re rich, you’re going to have many more options in fiberglass-unless you live in the Netherlands.

 

[DDW]

It's easy to remove the paint from aluminum. Just give it some time and it will remove itself.

The problem with leaving it unpainted is that it forms an oxide layer which rubs off on you and your clothes.

 

[Mac2]

“Is there any way to tackle the corrosion from within in a steel boat or is it hoping that the yard that built the boat has done a decent job in giving the steel an anti corrosion treatment ?”

It’s all about the yard that built the steel boat. Properly sprayed foam insulation is the only way to go with steel IMO. Watch the latest YouTube channel m/v Delos. They just spray foam insulated their aluminum cat. Notice how it gets into the nooks and crannies. The expanding foam will be at least four inches thick.

 

[Mambo42]

How do you plan to use the boat? I wouldn’t even consider wood. Aluminum is great maintenance wise, but they are usually built for speed and they have huge engines. Maybe that’s what you want. The aluminum one in Alaska has the stern extension. Like most extensions, the props and rudders are in the same location, which will affect the steering performance. Steel HAS to be well insulated, or like the above pst stated, they will rust from the inside out (due to condensation). I have owned my steel boat for 7 years. Without a doubt, my steel boat is exponentially easier to care for than my previous 1985 fiberglass boat (blister job, stern delamination, window leaks etc). I still like fiberglass because you can repair everything, but I would pay attention to what was used for the core material (preferably waterproof). Painted aluminum-ugh! I just painted/repaired my aluminum flybridge (an add on). Paint doesn’t like to stick to aluminum, so it tends to bubble up when it starts to fail. The prep/etch is key. I understand why that aluminum boat got rid of the paint when it started to fail. Unless you’re rich, you’re going to have many more options in fiberglass-unless you live in the Netherlands.

We will use the boat basically the same as we use it now, sailing the Med, but during the busiest summer months (July + August) we will simply find a protected bay outside the charter areas and stay there for a longer period. We can do that with our current boat, but we basically lack living and storage space.
On top of that I want to be able to outrun the bad weather, so every one of these boats can do 15 kts (at least), compared to 6.5 kts now.

I have not been in the steel boat yet, did call with the yard that built it, but they have no more files on how it was built. From what I have seen on pictures the bilge has no foam insulation, I think it looks more like paint.

Am not sure I would want to have a boat in the Med without paint on it, think it will become boiling hot in summertime.

 

[psneeld]

Yes on hot aluminum in strong sun areas.

I wonder if vinyl wrap would be a better solution for aluminum than paint though it may not stick like paint either.

I am no stray current expert, but yes, your boat can be affected by someone else's stray current from what I have read. There are electronic detection and protection devices that can/should be installed to help.

Steel foamed on the inside...hmmmm.... not sure about that as a lot of commercial boats I have been on had plenty of rust under the foam and not what a mess getting all the foam off. Not that I have a good answer to the insulation problem... the biggest issue is cabinets, closets and other interior things that are difficult to see/work behind if not well thought out.

I haven't been on enough steel rec boats to toss around a lot of experience and my experience on ships and commercial vessels may not be directly relatable.

 

[SteveK]

Each geographical area will have the preference for boat hulls.
In the 70's around here wood was still common and many 50's and 60's built boats were around. So I had no hesitation, after inspection to buy a 71 woodie GB36 last decade, in fact the hull was in better condition than the house. In the 80 % 90's I noticed daylight through the hulls of GRP as they were built with as thin as possible after prior ones were overbuilt, so pre 80's boats are still popular today.
Aluminum and steel are around here but GRP appears to have taken the lead of popularity, I suspect because the retirement of tradesmen has left GRP the easiest to build and repair.
Your choice has to be based on local boat yards expertise and not be a unicorn.

 

[Mambo42]

Each geographical area will have the preference for boat hulls.
In the 70's around here wood was still common and many 50's and 60's built boats were around. So I had no hesitation, after inspection to buy a 71 woodie GB36 last decade, in fact the hull was in better condition than the house. In the 80 % 90's I noticed daylight through the hulls of GRP as they were built with as thin as possible after prior ones were overbuilt, so pre 80's boats are still popular today.
Aluminum and steel are around here but GRP appears to have taken the lead of popularity, I suspect because the retirement of tradesmen has left GRP the easiest to build and repair.
Your choice has to be based on local boat yards expertise and not be a unicorn.

I don't think a lot of yards here are familiar with aluminum. Steel will be a bit easier since we do have large yards for commercial shipping, some of them also do steel yacht maintenance.
Wood should be possible here as well since a lot of smaller boats and fishing vessels are still made of wood.
GRP of course is the majority here in the Med, but we don't have a lot of GRP trawlers here, in fact in all the years I may have seen maybe 10 in total.

Another factor that limits the search is stabilization. Either the boat has to have it already or the price needs to be low enough that it is still feasible to add them. Now that I have zero speed stabilization I don't want to go back to a non stabilized boat. All of these three boats are in the 70 ton range, have hydraulic stabilizers while underway (not zero speed), but their heavy weight should keep them more stable at anchor than my Defever without stabilization. At least that is what I hope. Since all three already have stabilizers it means space is available and perhaps increasing the strength of the hull even more won't be necessary.

 

[SteveK]

GRP of course is the majority here in the Med, but we don't have a lot of GRP trawlers here, in fact in all the years I may have seen maybe 10 in total.

There you go, GRP most popular will be easiest to work on. But then I am curious what is and is not a trawler in the Med. This is a trawler forum and many boats here I would not look at as a trawler, mine included.

 

[Mambo42]

There you go, GRP most popular will be easiest to work on. But then I am curious what is and is not a trawler in the Med. This is a trawler forum and many boats here I would not look at as a trawler, mine included.

The majority of the motor boats in the Med, at least my part of the Med, are the Princess, Fairline etc type boats. Boats like my Defever are extremely rare, in fact, I have not seen a single Defever in all the years here. But we also don't have sport fishing boats, that is typical a US style boat.

Then of course we have the super yachts and there are a lot of them during the summer. Next to that we have the charter boats, but the majority of them are sailing vessels. Power cats are rare. In Greece we have about 7000 charter boats, Croatia has around 5000.
The three boats I found are in between trawler and fast boats.

 

[Comodave]

I would absolutely go with fiberglass since it is so easy to work on. I add things and it is easy to glass them in. It is easy to repair. It doesn’t rust or corrode. It can blister but if you do am epoxy barrier coat you will ne good.

 

[Mac2]

Steel boats will not have insulation in the bilge where water is expected to flow. Mine starts at about a foot on each side of the center line. I have had to remove the insulating foam in a few places to add attachment points to the ribs. I had to use a vibrating scraper to remove it, but it was stuck so well it left a “fuzz” behind. As I stated before, the builder makes all the difference.

 

[Mambo42]

Steel boats will not have insulation in the bilge where water is expected to flow. Mine starts at about a foot on each side of the center line. I have had to remove the insulating foam in a few places to add attachment points to the ribs. I had to use a vibrating scraper to remove it, but it was stuck so well it left a “fuzz” behind. As I stated before, the builder makes all the difference.

The builder of the steel boat has a very good reputation............nowadays. I just don't know if they had a good reputation back in the days, this boat is almost 36 years old.

In any case, I think the aluminum one is not going to be the one.
This is the Benetti, built in 2001. Looks like a great boat, lots of space, good quality engines, good fuel consumption, but with no expertise in this part of the Med in aluminum, it is a huge gamble.

Vendita Barca BENETTI SAIL DIVISION - BENETTI 20 - Media Ship

Vendita BENETTI SAIL DIVISION - BENETTI 20 usato. Descrizione, foto e tutte le informazioni su BENETTI SAIL DIVISION - BENETTI 20 . Annuncio vendita barca BENETTI SAIL DIVISION - BENETTI 20.

www.mediaship.it

 

[Greg QS]

Wood no way. Period
Best is glass. For most
Steel and aluminum a tie. Old boat go glass lasts forever.

 

[Mac2]

The builder of the steel boat has a very good reputation............nowadays. I just don't know if they had a good reputation back in the days, this boat is almost 36 years old.

In any case, I think the aluminum one is not going to be the one.
This is the Benetti, built in 2001. Looks like a great boat, lots of space, good quality engines, good fuel consumption, but with no expertise in this part of the Med in aluminum, it is a huge gamble.

Vendita Barca BENETTI SAIL DIVISION - BENETTI 20 - Media Ship

Vendita BENETTI SAIL DIVISION - BENETTI 20 usato. Descrizione, foto e tutte le informazioni su BENETTI SAIL DIVISION - BENETTI 20 . Annuncio vendita barca BENETTI SAIL DIVISION - BENETTI 20.

www.mediaship.it

Good looking boat. Good engines and hp. Aluminum, so no corrosion. I would think you could get a good surveyor that specializes in aluminum to figure that part out.

 

[Pascall]

I have been told that you should not apply good (copper-based) antifouling to an aluminum boat, which seems like a major disadvantage to me.

Kind regards,

Pascal.

 

[Mambo42]

Good looking boat. Good engines and hp. Aluminum, so no corrosion. I would think you could get a good surveyor that specializes in aluminum to figure that part out.

She does look great and could be a good boat, but I don't think I have enough knowledge about aluminum to take this boat on. Am now going over the older videos of Gus (in too deep), after all, he also has an aluminum boat. He is talking about some sort of instrument which will tell him if the boat has too many anodes. Have tried to google it, but get no results.

 

[Mac2]

She does look great and could be a good boat, but I don't think I have enough knowledge about aluminum to take this boat on. Am now going over the older videos of Gus (in too deep), after all, he also has an aluminum boat. He is talking about some sort of instrument which will tell him if the boat has too many anodes. Have tried to google it, but get no results.

Steel rusts, fiberglass can blister or delaminate, aluminum-none of these. I know copper in water touching aluminum is an issue. Poor welding is the other issue I know about but they are easy to evaluate. A silver/silver chloride electrode is used to verify anode protection. I bought a thru hull with the electrode, but ended up not using it (long story) and instead bought the electrode that I could put in the water myself. Im thinking I would only use the test kit at a marina I didn’t trust, otherwise any problems would have shown up on a veteran boat. An isolation transformer on the aluminum boat would resolve any shore power issues.

 

[Jeff F]

My thoughts:
Aluminum is lighter than steel, so is used often for higher performance boats.

Glass is less common in bigger boats because of tooling costs. The builder needs to produce a number of boats to justify building the molds.

I've seen some beautiful newer wood boats. With modern resins and coatings I see that material as being entirely practical and viable.

I have a painted aluminum sailboat that's 25 years old and in good shape. But it's always been in fresh water. I wouldn't want an unpainted AL boat. I guess that's a personal taste, but I just don't like the look and feel.

I've dreamed of having a steel boat, but can't see any real advantage over the heavy FG build I now have. For displacement boats I think it could be great, with all the usual caveats.

 

[Mambo42]

The steel boat that I found belongs actually to a member (or former member) of this forum. He is selling it, I tried to contact him, to no avail, got in contact with the broker, but he wants me to make a blind offer and make a 10 % deposit on that boat. I understand that this is normal in the US, but not in Europe, it is a legal nightmare that I am not willing to enter. Besides that, why do we have surveys ? We do a survey to figure out the state of the boat and determine the value (at least here in Europe we get a value in the survey report).
The boat itself looks to be in good condition, but then again, I don't know when the pictures were taken. She is heavy, she has heavy engines, is stabilized (not zero speed) and she ticks all the boxes for us.
However, she is old and I don't know what the condition of the hull is on the inside. The broker was not really willing to give a lot of information about technical parts. I only got pictures of the interior, but had to drag all the answers out of him with regard to the technical items and then still did not get them all.
I was not so happy learning that the zincs in the engines get changed only once a year (regardless of the hours) and the zincs on the hull get changed once every 2 to 3 years. Since I have to change the zincs in my engines every 5 to 6 months I think a year is a bit too much.
Since we are talking about a member of this forum (although he does not react anymore) I don't want to post a link to the boat, I think that should be up to him. You can find the boat online, it is not so difficult. It is a Moonen and they have a good reputation. However, this Moonen was built only 10 years after the yard was founded, so were they really up to their current standard already ?
Negative part is that the boat is so heavy that there are not a lot of lifts available in the Med. I checked and found only 3 in the whole area where we are cruising. An emergency haul out is not an option with this boat.

The wooden boat comes from an Italian yard that basically still builds wooden yachts, even today. They have delivered over 500 yachts, so I think they know what they are doing. However, also here the broker was unable to provide any information on how this yacht was built. I called with the yard, but they have not replied to me yet.
The good part about this boat is that it had a complete refit and has not been used a lot since that refit. The absolute best part is that it is lying in Monaco (means it has been taken extremely well care of) and the owner is highly motivated to sell. However, it is not a trawler, but I checked with the engine manufacturer (MAN) and these engines can run at lower rpm without a problem. Since the engines are as old as the boat they literally guzzle fuel at speeds above 10 kts. At full power you could empty the tanks in about 10 hours time and there is 2000 gallons of fuel in the tanks. In Europe that would be a 15.000 euro fuel bill every 10 hours, which is basically absurd. At 9 kts the fuel consumption is acceptable (12 gallons per hour) and that will give me a range of roughly 1300 nm, which means I can go from one tax free country to another (like I am doing now as well). That would bring a refuel down to about 5000 euro, which is much more acceptable. You can compare this boat a bit with the Broward that Gus (in too deep) bought. If you run it slow you can get somewhere, otherwise you will be going from fuel station to fuel station.

The aluminum boat would have my preference when it was made out of GRP. It ticks all the boxes, although the living space is substantially smaller than the other 2. The other 2 are over 3' wider and 10' longer, that is a lot of space. Since we are more or less living on board, extra space is very welcome. But the aluminum boat also ticks all the boxes, I would only need to add solar and LiFePO4.

In the GRP category I have not been able to find anything in the Med that ticks all the boxes. Absolutely none of them is stabilized (in the price range I am searching in) and they are lacking a lot of equipment (water maker, solar, large battery bank, washing machine, dishwasher, modern navigation etc) which means an additional 150.000 at least to bring it up to speed.
The Flemings I found in the Med also need a lot of work and then I am still talking about a boat which is not much bigger than what we have now.

 

[Mac2]

Stay away from the wood boat. Can’t emphasize that enough. Resale aspect alone should be a deterrent. Moonen has a good reputation. I wouldn’t shy away from a boat built 10 years after founding. My boat was one of the first five built. It was way overbuilt. I don’t think the company lasted 10 years! I’m 90 tons and I worry about finding lifts as well. All my running gear is protected and all my tanks are built into the hull, creating double walls nearly all around the hull. Something to look into. If you anchor out a lot you will learn to love the weight as it really slows down the motion. Also ask the broker if the steel boat has been audio gauged lately. I change my anodes when they need replaced. If the boat hasn’t been traveling, it’s not going to have the same wear as yours (assuming you’re cruising). Good luck.

 

[Pascall]

A polyester boat under the Mediterranean sun has a tough time of it. The cell coat wears out within a few years and needs to be repainted, or you can polish it several times a year.
Blue hulls are particularly prone to this and are therefore referred to as jeans boats.
Now you're getting the answer from a true steel enthusiast, but when I see how many hours are spent polishing the polyester yachts in our marina with a polishing machine, it's not comparable to the maintenance of our steel boat.
My wife and I paint our boat ourselves in one week, approximately every 6 to 7 years.
If we find a spot of rust in the meantime, we repair it immediately. This takes us about 4 hours a year. Otherwise, we do nothing to the paintwork, except for the occasional wash.
The boat is always in salt water, summer and winter, and is always in mint condition.
It is essential to tackle rust as soon as it appears. Of course, the basis of the paint system plays a major role; it must be good.

Kind regards,

Pascal.

Translated with DeepL.com (free version)

 

[Pascall]

mistake

 

[Shrew]

For a recreational boat, I would be primarily focused on GRP.

Steel is for commercial or if you're venturing into a region with ICE, or possibly a huge amount of logs.

Aluminum can also corrode. IMHO it looks horrible and leaves oxidation behind.

 

[Mac2]

Aluminum can also corrode. IMHO it looks horrible and leaves oxidation behind

How does aluminum corrode?

 

[Mambo42]

For a recreational boat, I would be primarily focused on GRP.

Steel is for commercial or if you're venturing into a region with ICE, or possibly a huge amount of logs.

Aluminum can also corrode. IMHO it looks horrible and leaves oxidation behind.

I agree with you on GRP, however nothing is for sale that fits price, specifications and in the area where I am. All I can find needs a lot of work and that would put it at least 50 % above the prices of the other boats. And I probably would not see that money back when I would sell the boat. I am not a big fan of any of the options, mostly because I have no knowledge about them.
It is one of the reasons why I am now actually thinking about lengthening my current boat.

 

[Shrew]

How does aluminum corrode?

Disintegrate might be a better word.

However, I did find this:

cor·rode
/kəˈrōd/
verb
1.
destroy or damage (metal, stone, or other materials) slowly by chemical action.

Aluminum corrosion is the gradual breakdown of its protective oxide layer, often through pitting, caused by factors like chlorides (salt), extreme pH (acids/alkalis), moisture, high temps, or contact with other metals (galvanic corrosion), leading to material weakening, though it doesn't "rust" like iron. This process exposes fresh aluminum, forming more oxide or hydroxide, creating white powdery deposits and deep pits that compromise strength, especially in marine or concrete environments.

Causes of Aluminum Corrosion
-> Chloride Attack: Salt (from seawater, de-icing salts) breaks down the passive layer, causing localized pitting.

-> pH Extremes: The natural oxide layer (pH 4-9) dissolves in strong acids or highly alkaline conditions (like concrete/mortar).

-> Galvanic Corrosion: Contact with more noble metals (copper, steel) in a wet environment creates a battery, sacrificing the aluminum.

-> Moisture & Crevices: Trapped moisture in gaps (crevices) accelerates corrosion.

-> Erosion-Corrosion: High-velocity water (e.g., on roofs) can damage the film.

-> Wood Contact: Acids from certain damp woods (cedar, oak) corrode aluminum.

Aluminum Corrosion: Why it Happens and What to Do When It Does - Wiley Metal

Choosing aluminum over steel for metal fabrication doesn’t solve corrosion concerns. Learn what causes corrosion and how to prevent it.

www.wileymetal.com

 

[Mac2]

Disintegrate might be a better word.

However, I did find this:

cor·rode
/kəˈrōd/
verb
1.
destroy or damage (metal, stone, or other materials) slowly by chemical action.

Aluminum corrosion is the gradual breakdown of its protective oxide layer, often through pitting, caused by factors like chlorides (salt), extreme pH (acids/alkalis), moisture, high temps, or contact with other metals (galvanic corrosion), leading to material weakening, though it doesn't "rust" like iron. This process exposes fresh aluminum, forming more oxide or hydroxide, creating white powdery deposits and deep pits that compromise strength, especially in marine or concrete environments.

Causes of Aluminum Corrosion
-> Chloride Attack: Salt (from seawater, de-icing salts) breaks down the passive layer, causing localized pitting.

-> pH Extremes: The natural oxide layer (pH 4-9) dissolves in strong acids or highly alkaline conditions (like concrete/mortar).

-> Galvanic Corrosion: Contact with more noble metals (copper, steel) in a wet environment creates a battery, sacrificing the aluminum.

-> Moisture & Crevices: Trapped moisture in gaps (crevices) accelerates corrosion.

-> Erosion-Corrosion: High-velocity water (e.g., on roofs) can damage the film.

-> Wood Contact: Acids from certain damp woods (cedar, oak) corrode aluminum.

Aluminum Corrosion: Why it Happens and What to Do When It Does - Wiley Metal

Choosing aluminum over steel for metal fabrication doesn’t solve corrosion concerns. Learn what causes corrosion and how to prevent it.

www.wileymetal.com

Galvanic corrosion is the only one I see that relates to boats, but that applies to all boats. A aluminum boat sitting in salt water can’t corrode on its own unless there is an external chemical reaction of some sort, correct?