[nerdblaster]

i'm looking to replace the old gas mercruiser 230's in my bertram 28. They're carburated so some new injected gas engines would obviously be more efficient.I'm just wondering, is it worth the extra cost to drop in diesels. I know they'll last a lot longer and be better on fuel, but theyre quite a bit more expensive. Would fuel savings be enough to offset greater up front costs of diesels? I'm a seasonal boater, may to october, averaging about 250hrs a season. Any input would be great!

[Loren Schweizer]

The easy answer is a resounding "NO".
With your current usage, you'll spend, what, $10-12K per season on gasoline?

Now, add up the cost of your replacement Yanmars or Volvos. Then, double that figure, which may be too high or too low (not likely) depending on whether you have a yard do this work, or are you doing the swap and paying yourself $.05/hour?
Then...
Propeller shafts may be the wrong diameter or length.
Propellers will have to be changed to the correct pitch & diameter. Which you'll figure out after the fourth or fifth try.
New engines are coming with a new wiring harness, right? And gauges.
Is the exhaust piping & muffler size compatible with the back pressure restrictions as spec'ed by the new engine mfg'er.?
Will the old wooden engine foundations allow the new motors to properly target the shaftlines and will the engine hatches close all the way?
Diesels have a return fuel line; gonna have to replumb the fuel tank.
Are the raw water intakes/strainers/hoses properly sized?

And then... there may be other issues that appear: bigger starting batteries & wiring required? And, and...

You'll be buying a lot of Racor fuel filter elements and changing oil at shorter intervals to protect your new babies.

Gonna take the better part of a season to fix leaks, adjust here & there, and generally maintain the new installation as things settle in.

[brianwill]

Why don't you consider replacing the gas engines with a single diesel? Most of the commercial fishermen (and most long range trawlers) use a single diesel.

[CYS]

Mr. Schweizer gives sound advice. One caveat that remains is the fact your boat is 28 Bertram. These particular boats enjoy a resale value far beyond their (legendary) sea keeping abilities. The boat is worth whatever it costs to restore or improve. A very unusual circumstance when speaking of boats. That said the machinery space provided on your boat is not large, nor is the exhaust or engine bearers. I would suggest, highly suggest, installing a fresh set of 6.2 Mercruiser packages with gears and full Smart craft instrumentation. The added torque and HP will make her a new boat to drive. Prop work will of course be needed. I feel that diesel would be a huge mistake. The new generation gas engines and extra ponies will increase your efficiency and range dramatically. Not to mention the pride and value of you boat.
Regards,

[Portline1]

Better fuel economy, safety, higher resale value, the list goes on. However the cost of doing it will not be cheap and it has to be done right. A single diesel would be OK, but then you will have a one off jury rigged set up and it won't be worth as much. Modern diesels can fit in smaller engine rooms, and if you do your homework it is possible. Check out the new Volvo IPS drive system, Sweet!

[mariog]

IMO, If your going to keep the boat, diesels are the way to go (Cummins factory remans are great) if you only plan on keeping her for a few more years then afterwards sell, stick with gas and drop in new crate engines for a few thousand dollars. and enjoy!

[Capt J]

I would say yes, as with a 28' Bertram you will get a much greater resale with diesels. Gas engines in a few years will just be used gas engines and resale will not be much more then what you have.

I did a delivery on a 28' Bertram SF a few years back that had Yanmar 175hp diesels installed and the boat ran great and had great fuel economy. Although another friend installed the 240hp yanmars (I feel they are a much better choice). The 175hp's cruised the boat at 19knots getting 1.5 mpg this was with a very large hardtop. Which greatly increased the range since if I remember correctly it only has a 120 gallon fuel tank. The 240hp's in my friends 28' express cruise it at 28 knots and it gets better fuel economy and rides much better at that speed. With the 175's you had to use almost full trim tabs to keep it at 19 knots, without using the trim tabs it would only cruise at around 16.5 knots. Engine access is very good on all sides with both motors.

[viking 40]

Some where, I heard a figure of 500hrs per year and diesals will be worth it. At 250hrs per year, you're probably better off swapping them out with anouther set of gas engines.
i would bet though, you've never owned a boat with diesals. I've never met anyone, who has gone back to gas, from diesal.
If you are serious about disals, repower your boat with gas, keep 1 year, sell and by a boat with diesals in it. just my 2c