If you would like to own a new, large,
seaworthy convertible that is selling anywhere from $1.8 million to $4 million,
and you know you’ll never be able to afford it, recent events may have put that
dream – or something close to it – within realistic reach. An interesting thing
has happened in the last nine months. First, most convertibles built in the 1980s
were powered by (now-obsolete) Detroit Diesel 2-stroke engines which were selling
at a discount far greater than their age would indicate on the used boat market.
Then, last summer, high fuel prices caused large boats to be discounted farther.
Finally, the economic decline the last six months has caused many used boats to
fall another 30%. The cumulative effect of this has been to make some classic 1980s
convertibles so inexpensive, that they can be repowered with Yanmar diesels and
still only cost from 15% to 30% of similar brand new models – and go faster and
burn less fuel than they did the day they were new some 20 to 30 years ago. Join
us as we show you the dollars and sense of repowering of a 1984 Hatteras 52.
There are over 50 Hatteras
53 convertibles from 1980 to 1990 currently on the market from $195k to $400k.
Many large convertibles and motoryachts built in the 1970s and 1980s were powered
by Detroit Diesel 2-stroke turboed and intercooled V-71s. Detroit Diesel WWII-vintage,
low-horsepower 2-stroke diesels were hopped-up with Rube Goldberg bolt-ons to produce
the energy that the new generation of semi-displacement boats needed. Their blocks
were never intended for the tremendous horsepower that they were later required
to produce. For example, the DDA 12V71TI rated at 850-hp new in 1986 started life
decades before as a 350-hp naturally aspirated engine.
These engines were/are notorious for leaking oil, blowing injector tips, smoking
and generally being problematical. General Motors, which owned Detroit Diesel back
in the 1970s and ‘80s, refused to spend the money to design and build new engines
made for the higher speeds builders wanted to attain in the go-go years of the 1980s.
Roger Penske bought the engine maker just as their 4-stroke Series 60 was being
introduced, an engine that went on to be very successful.
Repowering With Yanmar
For the last 15 years one of the most popular and successful re-power engine brands
in the U.S. has been Yanmar. There are several reasons for that:
First, Yanmar has specialized in repower. It devotes tremendous resources to consumer
service which makes repowering happen and be successful. The engineering and sales
time that goes into one repowering installation is almost the same that does into
selling a builder on using an engine in production for dozens of boats. That is
why most engine makers and distributors are simply not willing, or interested, in
devoting the time that it takes to this kind of customer service for individual
Second, generally, Yanmar engines are lighter and often smaller packages. This makes
installation easier. Being lighter is always good. Some of its engines have the
best horsepower to weight ratios in their class. Generally they are higher speed
diesels, which the market and the industry embraced as their reliability was proven
over the years and when other companies also came out with higher-speed engines.
Thirdly, Yanmar engines simply cost less in most cases than the engines that they
Picking the Right Boat To Repower
If you would like to own a large, seaworthy convertible that has been tested over
30 years or more, you can not go wrong with the Hatteras 52. It was built of solid
fiberglass which is nearly indestructible. Their topside styling is classic. Its
bottom was a classic Jack Hargrave design.
There is nothing like owning a new boat, but they are very expensive, and if you
can not afford it, the next best thing is repowering a classic old boat, such as
the Hatteras 52. In fact, from our perspective, the Hatteras designs from the 1980s
have held up very well from a styling point of view. Obviously the condition of
their interiors will vary from boat to boat. Some have been recently rehabbed and
are on the market, others can be put in nice condition for as little as $20k and
there are yards which will rehab the whole inside of your boat for something on
the order of $100k or less.
This week we will look at repowering a Hatteras 52 with data based on actual repowering
projects by Mastry Engine Center in Florida. (In two weeks we will look at repowering
a Bertram 46, a job done by Mack Boring, in New Jersey, the Northeast distributor
for Yanmar.) We’ll give you the total cost for repowering as well as the performance
numbers after the project was completed.
Refurbishing a Hatteras 52
The Hatteras 52 was one of the most popular models that Hatteras ever built. We
have picked the period of 1980 to ’88 as our sweet spot, but you can go back even
farther and find units still cheaper.
Hatteras boats have always been painted rather than have gel coat. Obviously, you
will want to find a boat that has been painted fairly recently. A good AWLgrip or
Emron paint job should last 10 years and still look good. Hatteras, Bertram and
Viking during this eight year period were unquestionably the best boat builders
in America and maybe the world. Nevertheless, when buying even one of these brands
that old you must have a good surveyor go through the boat and make a close inspection.
After the engines, electrical and plumbing are your top concerns.
The New Yanmar Power Package
The 1984 Hatteras 52 in our case study was powered by DDA 12V71TIs of 850-hp and
were replaced by Yanmar 8SY-900-hp diesels driving through Twin Disc MGX 5114A 1.92.1
marine gears, turning ZF 32x37x4 props.
Taking the Engines Out
While to the layman it might seem nearly impossible to get the old engines out and
new ones in, in fact it is a fairly easy process for those boat yards which are
used to doing it. First, the aft bulkhead of the house is removed. Then the galley
appliances are taken out along with the settee and furniture. The sole of the salon
is then pulled off, or hatches above the engines are removed.
Different yards use different techniques to remove the old iron. Sometimes an “A”
frame is constructed in the salon to raise the engines, and sometimes a forklift
or some other equipment is used to pull the engines out. New engines beds are installed
and then the new engines are “dropped” in. Perhaps the most time consuming work
is hooking up all of the plumbing, controls and wiring once the new engines are
in. Obviously, this is where the expertise of the yard is of critical importance.
To a large degree, the engine room undergoes a major overhaul.
This is another reason why it is important to have an engine distributor that has
the personnel, expertise and the enthusiasm to work with individual boat owners.
New Life in the Old Girl
Below is a performance chart of the Hatteras 52 after the new 900-hp Yanmars were
installed. While we don’t have performance numbers for the boat with the old engines,
we can tell you from our own personal experience with a Hatteras in this size range
with 12V71TI Detroits, that the boat runs with the Yanmar 8SY-STP engines about
six to eight knots faster top end and burns at least 20 gallons an hour less at
Mastry personnel supplied BoatTEST.com with the numbers above. The test was conducted
with 700 gallons of fuel aboard, six people, in calm seas and ambient temperature
was 69-degrees F.
The complete cost of the repower for the Hatteras 52 with the engines installed,
including all installation work would be about $212,000. Assuming a boat in good
condition could be purchased for $250,000, then the cost of the boat and the repower
would total about $462,000. New convertibles in this caliber of boat generally cost
between $1.8 and $2.4 million. That means that the repower project would cost from
about 19% to 26% of a new boat.
That price certainly put the fun, seaworthiness, and a lifetime’s dream within reach
of many more people.
If you have a specific repower installation in mind we suggest that you call a Yanmar
distributor and find out their recommendations as to the specific engines should
be installed and their cost. We have worked with both Mack Boring and Mastry Engine
Centers and can attest to their expertise and knowledge. They can also recommend
a yard near you who can do the work in a professional manner.
Central and Northeast U.S.-- Mack
Boring & Parts Co. website…
Southeast U.S. -- Mastry Engine Center
Next: Repowering a Bertram 46
In the next issue of Offshore Motoryacht we will bring you an actual re-powering
story on the Bertram 46. Like the Hatteras 46, there are 50 of them on the market.
Check them out and we’ll give you the cost of repowering in two weeks.