Marinette Aluminum Boat Maintenance/Why a Marinette

Why a Marinette - The Forum's boat owners speak out. [1] The bad, the good and the ugly.

I am assuming either you own a Marinette or are looking to buy one.

From Fred

I'm going to go out on a limb (I use to really catch hell on the Catalina 30 forum every time I criticized anything about the boat) and say if I had the money I'd trade my Marinette in for a fiberglass fast trawler in a heartbeat. It's not that I don't like the Marinette, but it has some characteristics that I'm not wild about:

1) Trilux bottom paint (and all others safe for use on aluminum) sucks. I would give anything to be able to use VC17 on the bottom of the Marinette. A quick rinse and wipe with a scotchbrite pad and freshwater, let it dry and you're ready to paint (no sanding ever), dry time between coats less than 5 min instead of 12hrs, can paint in the fall and launch in the spring without losing effectiveness, and can paint 10 minutes before launch to touch up those areas under the boat stand pads, plus you get a little bit more boat speed compared to ablative paints - what's not to like?

2) Compared to my sailboats the Marinette is not nearly as seaworthy. I'd never even consider taking the Marinette out in conditions even half as severe as what I didn't think twice about going out in my sailboat. Heavier (i.e. fiberglass) powerboats with a deep vee hull that I've been in, while still not as good in heavy weather as my sailboats have been, are noticeably better than my Marinette. It's without a doubt the worst handling boat I've been on or operated when it comes to rough water operation. Don't get me wrong - I'm not saying that its not seaworthy at all - just that I'm not impressed with its handling characteristics compared to other boats I've had experience with, and I pick my weather windows with far more care when cruising.

3) Fuel economy on planing boats is awful compared to sailboats and trawlers. While Marinette's are better than fiberglass boats of the same size that's still not saying much.

4) Fiberglass is easier to work with than aluminum (at least for me). Getting paint applied properly on aluminum is even more of an ordeal than on other materials and preparation is critical.

That said, there are a lot of good things about these aluminum boats which is why I bought mine:

1) They tend be priced a bit lower compared to fiberglass boats that I was considering at the time.

2) No worries about core rot, blisters, etc. After having to recore the cockpit floor in one of my sailboats because some moron installed some hardware years earlier without caulking the mounting bolts, this is a feature that I really, really appreciate.

3) A bit cheaper on gas because of the lighter weight and less vee in the hull compared to fiberglass planing hulls.

4) Easy to work on as most things are accessible directly or by removing screwed on panels, which is a real blessing for those that do most maintenance themselves. I really don't get why most boat builders feel the need to install things in such a way that they are nearly impossible to service later.

5) My Marinette is a far more spacious and comfortable boat for dockside living and cruising than any of my sailboats have been, although I don't have nearly as much storage space compared to my last 30' sailboat, but the storage space I do have is more easily accessed, e.g. you don't have to dig into lockers stuffed behind settee seat backs.

6) My cruising speed of 18-20mph is wonderful when cruising. I no longer need a minimum 4 hour weather window to get from one port to another on Lk MI. On our cruise to Frankfort, MI this summer we encountered 6-8 ft very steep waves one morning. By 4 in the afternoon the waves had decreased to about 2 foot and by 5:30 we were two ports further down the lake. In a sailboat or trawler we would have lost the entire day. Plus the extra cruising speed extends my range considerably. Unfortunately with today's fuel prices I think twice (or more) before actually traveling the extra distance.

7) The Marinette is built like a tank - its almost inconceivable that you could damage the hull beyond repair. We hit rocks in Lake Huron at the end of our first day with my Marinette in the thickest fog I've ever seen (first time I've ever seen fog combined with a thunderstorm). Both props and shafts were bent but had no damage to the hull.


Other Comments:

Fred: I agree with virtually every one of your points.

From Fast Jeff

Here's a few comments of my own:

Copper-based AF paints are in the bull's eye of environmentalists, so Trilux type paints may be the only ones available in the future. (That's good for us, for the price will come down.)

On rough sea keeping: My 1985 (28 foot) Bayliner (deep vee) handled rough water better, but removal of the flybridge did help. The shallow draft and lightness of a 32 footer makes for a tippy boat in the big ones. The 37 footers (like Louis') and larger handle much better.

On maintenance access: I curse a blue streak anytime I have to work on the outside sides of the engine--God help me when the manifolds need replacing! But at least you can get ot things. On the old Bayliner (again) a Sawzall would be required to change out the fuel tank--it's stuck under the aft cabin! (What were they thinking?)

On spaciousness: A winner hands down when it comes to live-aboard space (and windows! I wouldn't own one of those plastic boat "caves".)

Gas mileage--a real concern to all of us--is definitely better on a big M. Been keeping an eye on what MPG newer boats get, and ours win hands down for an inboard. Plastic boats with I/Os, and with dual props, are a bit better in many cases, though.

From phflaw All are welcome. (Hell, even lawyers)

I, for one would not trade my boat for anything other than a bigger Marinette. We use our 32' sedan bridge as a sort of floating summer cottage. Life seems to slow down when I've got my family with me on the boat. I've owned wooden, fiberglass and now aluminum boats and I'm sold on aluminum. My next boat will be a 37' or 39' aft cabin Marinette.

From Sick Leave

I have a twin 28 footer only regret is wishing I had the 32 footer. I have so much time and energy in this one not sure I want to buy a 32 and start over. Almost bought 32 last fall from some one near here but could not get a commitment for bigger well at marina where I am. Did not want to change Marinas and still do not, the costs are cheaper in current marina.

From Yoobertube

Most of the comments you will get are about the 28' and 32'. These are great lightweight planning hull boats. 37' and 41' are very much larger and better in rougher conditions. All are very tough.

From GB49

To Hunter,

Good move on thinking about Marinette. They are the most affordable, livable and seaworthy boat on the market, IMO. My 3rd summer living aboard my 32 sedan is coming to an end and every year it’s a painful departure. I wish I could keep her in the water year round...but in a warmer climate. If you do get a Marinette I can tell from reading your history you will become attached to her in no time. I don’t know what the heck I'd be doing now if there was no boat in my life. I would never trade my 32' for an equal size plastic boat. Partly because most 32' plastic boats don’t come close to offering the space a Marinette does and partly because of the fuel economy. Yes, you may trade a little comfort in foul weather for less weight and shallow draft but physics is physics and I have yet to hear of any Marinettes rolling over because they are "top heavy". They can take a lickin and keep on tickin.

Welcome to the forum, Karl

More from GB


All valid points, but.. 1) Bottom paint on any boat sucks. Until the day someone designs a boat rotisserie device like they use when rebuilding cars, applying bottom paint will always be a pain in the neck, butt, elbows, and knees.

2) Sailboats to Power Boats are apples to oranges. Completely different hull characteristics and capabilities.

3) Fuel econ, again apples to oranges.

4) Fiberglass (FRP) is easier to work w/ but Aluminum you at least you have something work with if you happen to pile up on reef or ram into a lighted channel buoy at cruising speed and make it back home w/ no assistance. (Yes, someone I know did this w/ a 32’ sedan) Al has much better tensile qualities.

Yes, Marinette has its share of foibles, but the fact that you can find 70s and 80s Marinettes in the classifieds of many boat magazines, most (some, ed) of which I admit are in crap condition, but none the less are still in operational existence says it all. I don’t see many fiberglass boats of similar type from those years advertised anywhere.


From John Althouse

Info on Aluminum alloys used on Marinette's. The hull, deck and superstructure plating is 5086 aluminum (5086 was developed for salt water use, it can be used for both fresh and salt water applications)

The extrusions on the boats are 6061 aluminum. Extrusions are anything other than flat plate, such as angles, flat bars, tubes, the air foil shapes used for the legs on the shaft struts, the keel and sheer extrusions, etc.

5086 is difficult alloy to extrude, which is why 6061 is used.

These two alloys were used together on all of the boats from the beginning in the early 50's.

The filler metal to join the two alloys is 5356 alloy wire.

All 5000 series alloys are not created equal, unlike 5086, 5052 alloy should only be used in fresh water, in salt water it will rapidly deteriorate. Many small aluminum boats and aluminum houseboats are made with 5052 and generally do not last long when left in salt water environments.

A quick note on the history of the original company. In 1990 the airport in Louisville (where the boats were built from 1953 to 1990) was expanding and terminated the lease on the buildings that Aluminum Cruisers was using. The company had to move. Instead of moving, the company was sold to a frp (fiberglass) houseboat manufacturer in TN. While the new owners built a few Marinette (4-6), they never got a production line going again. Shortly after the purchase they became extremely busy with there houseboats as a result of the luxury tax killing the cruiser market and boosting the houseboat market.

In 1996 the assets and manufacturing rights were sold at auction and a few months later I purchased everything.

John Althouse President Marinette Yachts

From Joe JOE3656 (Marinette Forum Author)

I love the Marinette, but unlike some I upsized early (selling my 28 ft for a 37ft). A Marinette tends to be someone's second or third boat. The 37ft is far more stable. I numbered the biggies on the negatives.

See our aluminum page on this site.

Aluminum and Metals

Negatives - #1 - The moronic use of the damn Goo that was used in the bilge. Bilges should be "painted" grey or white with epoxy or zinc chromate paint to see oil leaks and to protect the hull. You must keep the bilge clean of dropped metal parts. (Water is fine). #2 A seahorse in tutu logo. #3 You have to keep the wiring and corrosion system in shape. Keep power from going into the hull - bilge, keep the galvanic isolator in shape, and pay attention to the CAPAC meter. Dropped a penny or bolt into the bilge - go find it. #4 This boat's life span works against it in resale. It exceeds the NADA age curve, so there are a lot of them on ebay to compete with when you sell. Lot's of very good 60's 70's and 80's boats to buy lowers the resale value. (Good to buy, bad to sell).

Trivial Negatives: Shallow draft - It's a river and lake boat, that needs modification for deep water (windows and cockpit mostly). Generally undervalued - The long life of Marinettes make them lower in resale value due to the comparison with similarly aged FRP boats. The quality is not well known. Some owners won't understand about what to put against aluminum (Stainless screws into the hull are a no-no), so you may have to fix some one else's fix. Antifouling paint is more expensive. You have to put anodes on the hull. Sedans and expresses - the plywood - Nautolex cockpit deck was OK for it's time, but damn, it could be better. Noise - Aluminum is noisier with wave slap and engines. You may have to insulate some of it. Smaller Marinettes are light enough to bob. The original stainless railing attachment is just a corrosion pain. You have to pull these off and rebed them on most Marinettes with 3M 4200 and proper gaskets. Painting requires the right self-etching primer.

Some parts of the appointment of a Marinette (the exterior plywood-Nautolex deck, carpet and some fiberboard interior panels) are of less quality than I'd like. These are generally upgraded by smart owners. When possible - use teak or solid panels (King Starboard), or aluminum plate panels to replace parts and see our pages on deck replacement alternatives (plasteak, aluminum plating, et al). Think white or plate aluminum outside as nice looking brown or grey colors are burn your foot "hot" underfoot. The deck railing fittings should have been welded aluminum.

Myths and half truths about Aluminum : There are myths about seawater corrosion which is not a problem with this boat, if basic common sense rules are used. You'll replace steel parts, the stainless steel rudders and the engines, but not likely the hull. (BTW Marinette Marine did not make the Marinettes, Aluminum Cruisers did.) You will have heard that aluminum fuel tanks made of Al (especially 60XX or 5052 series) do fail if improperly installed, but it's not the same issue. In FRP boats with Al tanks. the foamed in aluminum tanks form a battery effect as the foam breaks down over time, acidifies and entraps moisture. This is not the case of this boat. Al tanks should be 5083 or 5086, not 5052.

Myth: What you heard about on the Foaming of AL tanks.

Foaming in any metal substance is a bad idea. All plastics permit some water to permeate them and foam allows water to pass through. The tank must be separated and have vented aeration. Even worse is stainless in Foam which suffers from in low oxygen dampness. See The correct way is to paint the tank with zinc chromate or epoxy and use 3M 4200 or 5200 adhesive on the mount points as bedding compound. If you found that hard?... read at David Pascoe's site about permanently fixing a blistered FRP hull.

Myth : DC current (electrolysis) and Hulls

In all cases, fiberglass, steel, plastic or aluminum, a bilge with DC power is in trouble. Yes, Aluminum is more susceptible, but bronze through hulls, out drives, rudders and shafts are also susceptible with the same problem. It takes a couple of days to weeks to destroy a through hull (See the 3 days it took for DC to eat a fitting at, and also check the Quicksilver article at BoatUS article. It does not matter what type of boat it is, ensure live power does not get into the bilge. Pull any recreational boat periodically to check anodes, or install an impressed current system. Isolated bronze through hulls are not a problem, (but don't connect them together or to the hull). If the bronze is pinkish tinged, replace the fitting.

Try Googling for Marinette Aluminum Hull failure and then google fiberglass FRP hull failure. A bit anecdotal evidence, but insightful. All Marinettes are generally protected by Zinc Chromate or Epoxy-based hull paint. Most Owners use 3M brand 4200 as a bedding compound.

Forum Poll : What metal failed last on your Marinette boat? Steel - Rust/crack 9 votes (45%) Stainless Steel 6 votes (30%) Aluminum 3 votes (15%) Bronze 1 votes (5%) Brass 1 votes (5%)

By the way: For me, stainless failed at the rudder post. (Oxygen starvation corroded it). I am also going to have to replace steering cables (Steel). Chances are the bronze through hulls need to be checked or replaced.

We asked - 2 of the members with aluminum used a $10-20 fix to patch a spot.

Positives - Cost - I've been able to spend less and get more. Oh my yes, A Marinette is the safest old boat to buy and fix up. (But get a survey.) You can get Chrysler engine parts and rebuilding a Chrysler or Crusader is cheap. Nothing that can't be replaced, rots out. No balsa or plywood strings. Keep the Chrylser engine, they are cheap to repower and rebuild.

Lifespan - these are 30+ year boats. They last. No bad years - though the Buick engines are a negative on early 60's boats.

Owner and forum support - lots of people own these and the forum and Marinette company can support you on advice, parts and projects. It's a big positive not to be in an orphaned boat. Plus a lot of company sill make aluminum boats and their support is available.

Price - Marinettes are deeply underrated on value by NADA, which makes them a bargain to buy. Really a bargain.

Space - Huge interior space compared to most boats, well appointed. The beam of the boat gives lot's of space.

Cool deck - The deck stays cool in summer due to heat loss from the aluminum.

Quality - The boat hull will not get old, blister or fail. General quality of construction is high, mostly solid teak or teak plywood interior and tank-like welded plate aluminum construction. It's a very good choice as a used boat and very fixable. You can fix almost any Marinette.

Good in salt water - many are on the Chesapeake Bay.

Safe - Very log and rock resistant for rivers and lakes with lots of floating logs. You will hit a log sooner or later in many rivers.

Shallow draft - key to navigating some areas of water. Rivers, canals, bays (Cheasapeake and Florida are big areas for the Marinettes), and lakes with logs and shallows are a great spot for the boat. (And this is more a positive than a negative in the silting in of US lakes and rivers.

Customizable - Owners add, lengthen, and remove parts.

Surveyors like them - generally they can pass a survey. A surveyor can yea or nay a Marinette easy. (No weird moisture in the hull. Boating insurance companies like them.

Welded not riveted - Long lasting monocoque hull instead of sectioned rivets.

Seawater is OK- when properly painted and zinced, the boat will not fail in salt water (Coast guard boats are unpainted aluminum).

Speed - It's fast for a cruiser. It's light and fast.

No "monkey arms" required - most things can be reached to be fixed. The "monkey arms" issue is an important safety issue in a boat, as what I can't see or reach can sink me.

No wood in the hull not even glassed in plywood - won't rot.

My family likes it - which means I can own this boat.

Looks - Good classic boat-y look.

Mounting - I can attach things anywhere, not just at mount points.

Poll : What length is your Marinette? 28 22 votes (29%) 32 28 votes (37%) 37 12 votes (16%) 41 4 votes (5%) something else 10 votes (13%)

Poll What year was your Marinette built? pre-1965 4 votes (6%) 1966-1970 6 votes (10%) 1971-1976 17 votes (27%) 1977-1982 10 votes (16%) post-1982( -1994) 26 votes (41%)

Our poll has an average age of a Marinette of more than 20 years, with none less than 10 years old.

Poll: I have fixed the aluminum hull on my boat due to corrosion - Never 15 votes (75%), 1 small patch 0 votes (0%), Couple of pits 5 votes (25%), Had to weld something 0 votes (0%)

Every Marinette owner I know, paints their boat. Top and bottom. Most prefer epoxy as a barrier coat while some use zinc chromate paint for barrier and patches. I last used Interlux 2000E with 5+ years and no problems.

Must Read: Truths about all boats

The most important question in owning a Marinette applies to all boats - Are you and your family ready to own a boat? Is the boat right for you and the waters in which you will boat? A boat is like a car, you have to take care of it, and pay the costs on maintenance. Boats need repair and maintenance. Leave a car in the driveway for 1/2 a year and watch it deteriorate.

Quality is important in boats and cars. There are cars that age faster than others and cars that last a long time. A older used good car is better than a newer used poor quality car (Compare a 1980 Volvo with a 1990 Yugo). This is even more true in boats. Today we see the warranty (5-10 years) on the hull of some large fiberglass (FRP) boats is less than any possible payoff time. Why pay 200K+ for a 32+ ft boat whose hull and interior won't last 20 years? Whether aluminum or FRP, there are good and poor quality boats. If you decide on fiberglass, please read David Pascoe's articles on fiberglass boats and hull defects (go to the forum's links page). Moreover, consider carefully buying any FRP boat that will or did stay long term in the water with a foam or balsa cored bottom (non-trailerable) or foam core. If you decide on a metal boat, see this site, our forum , Marinette, Inc , the Metal Boat Society and Michael Kasten's web page.

Expect to pay thousands of dollars in maintenance and parts on any boat of any size. It's the way it is. Do not buy any boat you can't afford costs and time for. If you are afraid of the expense, you cannot really own a boat.

Truth is, the most likely reason for a boat to sink is the through hulls, cooling, bellows failure, and the hoses. Maintain them, replace plastic with Marelon (Forespar), and check them often. Plastic through hulls are a hazard. Close the ones you don't need. Replace or repair your bilge pumps every 2 years, as a Rule, most of them are of poor quality. Pull the boat out at least every three years, as four years in the water is too long a time for my comfort. Mine comes out every winter, as my marina has no one to watch it over the winter here. Visit the boat. Boats in the water need power for the bilge (a reliable self bailing boat is a myth).

Decide how much of a project boat you are prepared for and always get a survey. Divide the time you expect to work on a boat by two. Buy a boat for the way you will be boating. Make sure you have a place for any boat and a place that will haul it out for maintenance. A boat's beam may be wider than your marina has a slip for. Hint: Most wives insist on a head.