255-hp Yanmar-Powered Carver 36 Mariner as Fast as 375-hp Gas Engines - 05/27/2009
Carver has built a “36 Mariner” at two distinct periods during the last 30 years. From 1984 to ’88 it built the model with two staterooms, then in 2004 the 35 Mariner morphed into the 36 Mariner and it is still being built to this day. It has one stateroom. Most of the Mariners no matter from what era they were built left the factory with twin gas engines. But in 2004 one of those Mariner 36s was powered by a 255-hp (continuous) 6LPA-STP Yanmar diesel. Amazingly, its top end was within 3/10ths of a mph of what we recorded in a sistership two years later powered by twin 375 Crusader 6.0 L HO MPI gas engines. This presents some interesting possibilities for someone looking for diesel power in an affordable 36’ boat.

Carver 36 Mariner
This is a 2007 Carver 36 Mariner, but 36 Mariners were also built in the mid-1980s. Almost all had gas engines.

The 36 Mariner is a “max cube” boat designed to cruise and give its occupants as much room as possible both in the cabin and on the flying bridge – and it has a cockpit, too! The boat’s long suit has never been speed because all of that superstructure was simply heavier than a 36’ express. Further, Carvers are priced to give the buyer “value” – not speed. BoatTEST.com tested a new 36 Mariner in 2006 and here is the Performance Table from that test done over 3 years ago—

Carver 36 Mariner Test Results

As you can see, WOT was 31.7 burning 50.9 gph and getting .62 mpg. However “best cruise” can’t really be figured out by looking at the table as there is no obvious “sweet spot.” The best way to find “best cruise” in this boat is probably to be aboard her and see what feels right. Our guess is that it would be at about 4000 rpm, going 25.9 mph, burning 33.7 gph and getting .77 mpg.

A sistership powered by twin Yanmar 6LPA-STP (255-hp @ 3600 rpm continuous; Max. 315-hp at 3800 rpm) produced the following results in 2004 according to the technicians at Mack Boring (Carver installed the engines) who conducted the test—

Carver 36 Mariner
*Range is based on 90% usable in the 250-gal. tank.

When we compare the two performance tables the first thing we see is that the WOT speed of the two boats is nearly the same, proving that under the right circumstances diesel power can be as fast as gas power. Mack Boring tested the boat with full water and fuel and 3 people aboard. BoatTEST tested the gas-powered Carver with a ½ load of fuel, ¼ water and 5 people aboard. We figure that the diesel-powered boat was probably about 875 pounds heavier than the gas powered boat, so the diesel boat might have gone exactly the same speed or even faster than the gas-powered one in a laboratory apples-to-apples situation which is pretty hard to achieve with boats this size.

Carver 36 Mariner Interior
This is the interior of the Carver 36 Mariner that was built from 1984 to 1988.

The second thing that jumps out is that there is a well-defined “sweet spot” for the diesels – with 3200 rpm being the “best cruise” speed. Diesels are usually set up to run most efficiently at 85% of WOT, and these engines were no exceptions. We see that at 3200 rpm the Carver 36 Mariner will go 25.30 mph and get 1.35 miles per gallon, which is good for a 19,500 lb. boat.

Now we compare miles per gallon and range at “best cruise” and it is here that the diesels shine as they almost always do, no matter what the brand. The Yanmar diesels get .58 more mpg, or 75% better mileage when we compare best cruise performance. At 4000 rpm the twin Crusader 375-hp gas engines drive the boat 25.9 mph and it has a range of 173 statute miles. At 3200 rpm the twin Yanmar 255-hp diesel engines drive the boat 25.3 mph and it has a range of 303 miles – 130 more miles or 75% more.

Carver 36 Mariner Interior
This is the interior of the Carver 36 Mariner which started production in 2004 and is still being built today.

The savings in fuel over the course of the life of the boat will be significant, plus diesels are safer, more reliable, and generally less maintenance than gas engines. Depending on your application, the range that diesels provide may mean a cruise destination you could not make with a gas powered boat. For example, good, clean diesel fuel is hard to find in the Bahamas. Having nearly twice the range insures that you will be able to make it to reliable depots in the islands. The same is true when cruising to Mexico or Alaska.

Carver 36
There are many of the 1980s-vintage Carver 36 Mariners on the market.

The basic dimensions of the 1984 Carver 36 Mariner is not much different than the 2004 version, although the look and the interior are significantly different. If you would like two staterooms, then, you may prefer the older boat. Find one that has been well-maintained and you may have a real bargain on your hands. We have seen them advertised for as low as $49,000, and you might be able to do better.

Essentially there is nothing wrong with these boats if they have been well maintained except for the fact that they have gas engines that are 20 years old, which is a long time for a gas engine, particularly one in salt water.

We have seen the 2004 models with the single stateroom advertised for as low as $125,000. New 2009 models are selling for from $220,000 and up.

Carver 36
The flying bridge on the 36 Mariner (both old and new) is huge and is ideal for entertaining. This is an old one.

We’re told by the folks at Yanmar that the cost of buying two new diesel engines as well as the cost of taking out the old gas engines and installing the diesel would be about $75,000.

Say you are able to get a well-maintained 1984 Carver 36 for $50,000. That plus $75,000 for the re-power with twin Yanmars will mean that you have $125,000 in the boat. Figure another $5,000 to replace pumps, hoses, and a few other things, and you’ll have $130 to $140k in a boat with two cabins – which is what the 2004 Carvers are selling for with only one stateroom and no diesels!

Carver 36
Many Carver 36 owners button their boats up with cruising canvas and enjoy them well into the late fall and cruise them far north in the summer.

Maybe the Carver is not your cup of tea. In the past we have done the same repowering exercise with a Hatteras 53 and a Trojan 10 meter. Essentially, the economics work out about the same for any good boat built during the 1980s, when you repower with diesels.

Now, scout out the used boat that you like and which fits into your budget, and then contact the folks at Yanmar to discuss the short strokes of exactly what engine model you should have and what it will cost. Yanmar specializes in repower and they would like to hear from you.

Visit the Yanmar website…

See other repower articles…