Are there any disadvantages to an aluminium hulled boat?

Question

Seaotters (I think the only people making aluminium narrowboats in England) claim lightness, efficiency, reduced maintenance etc. But I wonder what the disadvantages are. Would they stand up to a bump from a steel narrowboat for example? Or running aground on rocks? Is an aluminium hull really almost maintenance free?

Answer 1

All I can add to this is, because aluminum is softer than steel, it will dent whereas steel might tear when impacted. I have an aluminum canoe, and Friday I got a bit nervous when I could see lightening approaching through the trees. LOL

Answer 2

All else being equal, lighter weight floats higher in the water making it more likely to be influenced by wind, and more movement in waves.

Electrolysis can be controlled with sacrificial zincs -- kinda like high cholesterol, as long as you are diligent, your boat can live a long healthy life.

Answer 3

The only main disadvantage is there are fewer places to get the repair  if needed done. Aluminium is very resilient it will dent easier than steel but all hulls can be holed.I work with hgv bulk bodies and one customer drops old train axles into them so they can take abuse.Most Ali boats are painted and not left in the unpainted state witch oxidises and provides a grey protective coat,the only drawback with painting is the need to etch or key the suface with primer dedicated to ALI .It also pays you to have an extra anode or two if the water is brakish or salt.

Answer 4

An aluminum hull structure, built to the same standards, weighs roughly 35-45% less than the same hull in steel. If high strength is needed, the alloy boat can be built to the same structural weight as the steel vessel, and then be considerably stronger. For smaller vessels, steel is less optiumum as one must resort to a large water plane and a large displacement to carry the weight of the structure.

Aluminium has a far greater structural efficiency (ratio of a material's stiffness to it's density) than steel. This basically means that if an aluminium column and a steel column were designed to the same stiffness, the aluminium column would weigh roughly 57% less. For beams and panels designed to the same stiffness, an aluminum structure will weigh 48% of the equivalent structure in steel. Some people will argue that the strength of a steel structure compared to that of an equivalent aluminium structure is greater. This may be true but the difference is a marginal one, however one must take into account that the aluminium structure will weigh rougly one third less in weight than the steel which is a massive weight difference. If the two boats were built to the same weight then the aluminium structure would have a far greater strength than the steel structure.

Another major benefit of an aluminium boat is that if the correct grade is used it will, to a large degree, resist corrosion. The boats produced here at Sea Otter do not even need painting as the shell is virtually resistant to corrosion. Any paint seen on a Sea Otter boat is purely to make it aesthetically pleasing. On the other hand, steel boats require annual re-blacking and the certainty is that corrosion will diminish the steel rapidly.

One factor that many people wish to know is the price difference between an aluminium shell and a steel shell. An aluminium shell is rougly twice the price of a steel shell, however this is only a portion of the overall boat cost. This may put some people off aluminium, however the saying "you get what you pay for" is very apt when talking about aluminium. You may pay more for an aluminium shell, but the money you will save in maintenance will more than match the original higher price. Sea Otter boats realise economies of scale and a finished boat is only slightly more expensive than an equivalent quality steel boat. A final advantage of an aluminium boat is that it has a far higher re-sale value than that of a steel boat.

Answer 5

Boats that are made of aluminium are really maintenance free

and can take quite a bit of abuse.The only thing that I do not care for with them is if the water is rough,they are very noisy

from water hitting the hull.Hopes this helps answer your question.

Answer 6

not so good in salt water against corrosion also any iron....steel parts cause electrolytic corrosion when in direct contact with aluminium. an aluminium boat will come of worst in collision with steel hulled boat but if it isnt holed its easier to tap out dents.

Answer 7

I have a 30' Sea Otter (8 years old) - bodywork never been re-painted, don't even bother to touch-up the scratches!  And a narrow boat which doesn't have scratches has never been anywhere!!

They are made from a marine-grade aluminium alloy, the same sort of material used for harbour work boats, oil rig support vessels, the Swedish Navy, the Thames water police, some cross-channel ferries and life-boats.

As regards "a bump" from a steel narrowboat, a few years ago when returning to the Midlands from the National Festival at Beale Park, and just outside of Braunston, we were hit so hard by an out-of-control hire boat (being "driven" by a kid whose head barely came above the cabin) that we were pushed through the hawthorn bushes and up onto the bank!

The only damage to our boat was about a yard of the rubber fender was lifted.

We returned to our mooring - contacted Sea Otter who said to leave it with them.  Next week when we went to the Marina, she was sitting back in the water looking as though butter wouldn't melt in her mouth!  Sea Otter had collected her, trailed her back to Chesterfield, replaced the fender and returned her within that week.

Have you looked at the Sea Otter web site for more info.

Of course, the big disadvantage of owning a Sea Otter is that you feel compelled to join the Sea Otter Owners' Club (Countrywide membership) who run their own "Rescue Service" for members (if you are in my area - just phone if you need a new fan belt, address of a dentist, Vet or just a good pub) and to join groups at National Festivals or small group cruises (you can get 4 x 31' Sea Otters in the locks on the Caen Hill flight - that's a lot of wheelers!)

How can you get from the Trent & Mersey to Bristol to Walton on Thames and back in ten days?

Easy - Sea Otter trail you to Bristol Marina where you join a happy gang, you cruise to Walton, along the Avon, Kennet & Avon and the Thames, then phone Sea Otter to say "come and get us"

No probs with electrolysis.  Husband is a graduate metallurgist and wouldn't have anything but a Sea Otter.

A report from Sheffield University Metallurgical lab gave a report of "a life's expectancy in excess of 100 years".  I reckon that will see us out!!

Disadvantages:  They are lighter so a strong gust could be more of a problem than with a similar-sized steel boat; but have you ever tried to push off a steel boat which is wedged firmly against a bank?  You can do it single handed with a pole when you have a captive Sea Otter.

Answer 8

Aluminum is a great material. If it wasn't why are some of the best cars made of mostly aluminum? Carbon fiber is the only thing used widely in the automotive world that is lighter than aluminum and stronger. The first car to use an all aluminum body was the Acura NSX, which was a remarkable car in its time and still holds quite a bit of its value and anyone who tells you the body of one is trash is probably an arrogant closed minded and nostalgic domestic fanboy.

I too would be sceptical of aluminum if I hadn't dealt with it in school. I'm studying to become a machinist and if you go home from school and come back the next day there will be rust on any of the (non-stainless) steel you machined where aluminum you can come back the next day and it will look good as new. I avoid steel like the plague for this reason.

I don't claim to know anything about narrowboats, my family only owns fiberglass boats for fishing and an occasional big boat to take to the bahamas and other interesting places by their definitions. I don't know how fiberglass compares to aluminum but we've never had any problems with our fiberglass except right where it hits the dock, which while covered by a rubbery trim piece has managed to crack in some spots. I don't know if fiberglass is an option but I'd think an aluminum boat would be better in light of that evidence. You can't just put fibers back together - you can patch them but it still can't be "good as new" unless you know someone with some serious skills. Aluminum...if you got in a similar situation you'd just have to beat it with a hammer with a rag covering the affected area.

Answer 9

Yes Aluminium is maintenance free, and to the rocks all sailors avoid rocks and running into other vessels

Answer 10

yes, someone could attack you with a can opener in the dead of the night

(if electrolysis is a problem, try waxing)

Answer 11

i got a aluminuim hulled boat.nothing wrong with them least maintance of all types of hulls.easy to clean after a fishing trip.i can run mine up on the beach without any worries to damage to hull.dont spill battery acid on it though it leaves awhite mark ffs.i would reccomend a alloy hull over anything

Answer 12

The main downside to Alluminum boats is they are noisy. As long as sacrificial annodes  are maintained electrolosis shouldn't be a problem.

Answer 13

Aluminum is a very strong and lightweight  material. I have run and maintained many aluminum patrol boats. Yes they are noisier then fiberglass and many are insulated to help that. They can be repaired by a skilled welder if serious damage occurred. But be careful if operated in saltwater. Try to take out a stainless steel bolt after 10 years or so, when they have corrosion all around them. And if you are in an area with any stray electricity in the water (from other boats orthe marinas poor electrical system) watch out. Aluminum is very close to zinc on the periodic table and will quickly be eaten away by electrolysis if not taken care of. I love aluminum boats, but they are far from maintenance free. Coreten steel is a great choice, it just gets surface rust on it if scratched, or fiberglass is the closest to maintenance free you can get.