Defiance 34

A conversation among Whalers
GHMariner
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Defiance 34

Postby GHMariner » Fri Oct 05, 2018 2:54 pm

I am returning after perhaps ten years away from forum participation.

After owning many different boats over the years, ranging from a few Boston Whaler boats to larger cruisers and trawlers, I'm zeroing in on a 34-foot DEFIANCE as a possible next boat for our young family. I'd be selling three boats to make room in the fleet, sacrificing some features and flexibility afforded by having all those options, but consolidating into one boat to hopefully reduce maintenance and storage, while providing more of what we want in a single vessel.

Do any readers own a 34 DEFIANCE or have owned one in the past?

I'm curious about:
  • cruising speed and fuel consumption with the different engine options
  • ride comfort in various sea conditions, and
  • nuances of the layout and configuration--what you like and what you don't
  • model history

Information on a 34 DEFIANCE is hard to come by. I don't think very many were built. I don't even know what I don't know, so share what you know and maybe it'll spark more questions. Thanks in advance.

jimh
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Re: Defiance

Postby jimh » Fri Oct 05, 2018 5:37 pm

In c.2001 and 2002 there was a 34-foot Express Cruiser called the DEFIANCE. It had twin inboard Yanmar diesel engines and a Unibond fiberglass hull. Here's one of them I saw in-person and photographed:

Image
DEFIANCE 34, made c.2001 with a base price of $350,000. Sighted cruising the Atlantic Intracoastal Water Way around Ft Lauderdale back in 2001

Also the Commercial and Government Products division made some boats that they called a DEFIANCE that were quite different--they had aluminum hulls:

Image
DEFIANCE 30 aluminum hull boat with twin outboard engine power.

GHMariner
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Re: Defiance 34

Postby GHMariner » Fri Oct 05, 2018 6:36 pm

Oh yes, I'm talking about the express cruiser, not the CGP boat.

[Emended TOPIC and first several posts to reflect the clarification of "DEFIANCE" to DEFIANCE 34".--jimh]

vze2gbs4
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Re: Defiance 34

Postby vze2gbs4 » Sat Oct 06, 2018 1:26 am

Only sixty-three [DEFIANCE 34 boats] were ever build. Boston Whaler halted production due to the high cost of building them and very few sales. The first hulls were built at the Edgewater plant, and the rest were built at the Sea Ray plant at Merrit Island by Boston Whaler personal, from what I understand. Back in the day and at one New York city boat show I was all over [a DEFIANCE 34]. I loved the interior and the helm location in the middle. [When new in 2001 and 2002 a DEFIANCE 34 cost] about $350,000 to $400,000.

I saw two [DEFIANCE 34 boats] that partially went under [water] and were auctioned at bargain prices. [The DEFIANCE 34] is inboard-powered, and, even if the hull shouldn't sink, any excessive water on the deck could flood the diesel engines.

The [used DEFIANCE 34 boats for sale that] I saw still demanded six figures [i.e., $100,000 or more].

jimh
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Re: Defiance 34

Postby jimh » Sat Oct 06, 2018 7:11 am

GHMariner wrote:...I'm curious about...cruising speed and fuel consumption...


From the Boston Whaler specifications, the base engines were Yanmar 6LYA STE diesels rated at 350-HP. The dry hull weight was 18,100-lbs. To get a boat weight underway we add 2,100-lbs of fuel, 400-lbs of gear, and 400-lbs of people. This gives a boat weight of 21,000-lbs.

Assuming the hull characteristics are similar to other Boston Whaler hulls, we use Crouch's method to estimate speed with a hull constant of 180. With this input:

POWER = 700
WEIGHT = 21000
HULL = 180

the Crouch's method estimate for top speed will be 33-MPH.

To get the fuel consumption of the engine we look for a Yanmar data sheet. I found one for a similar engine, a 6LYA STP model that makes a bit more power, 370-HP. At full-throttle that engine burns 82-liters-per-hour or 21.7-gallons-per-hour. Twin engines will burn twice that, or 43.4-GPH. Since the engines in the DEFIANCE are rated less, we derate the fuel burn proportionally to 43.4 x 350/370 = 41-GPH

From the estimates of speed and fuel consumption we can estimate fuel economy; we calculate MPG:

(33-Miles / 1-hour) x (1-hour/41-gallons) = 0.8-miles-per-gallon

Cruising Speed and Fuel Economy

If the hull is like most Boston Whaler hulls, it will need to be pushed to about 27-MPH to stay on plane and get best fuel economy. Now we calculate engine power at that speed, again using the Crouch method:

MPH = 27
WEIGHT = 21000
HULL = 180

Crouch's method predicts 470-HP. Going back to the Yanmar specifications, we look for power output per engine to be 235-HP or 175-kW. From the Yanmar fuel consumption graph it looks like each engine will have to turn about 2,000-RPM to make that power. At that engine speed and load the fuel consumption is 23-liter-per-hour or 6.1-gallons-per-hour. For two engines that is 12.2-gallons-per-hour. Now we can estimate fuel economy at

(27-miles/1-hour) x (1-hour/ 12-gallons) = 2.2-gallons-per-mile.

To summarize, my analysis suggests the DEFIANCE 34 with the base engines of twin 350-HP diesel:

TOP SPEED = 33-MPH burning 43.3-GPH for 0.8-MPG
CRUISING SPEED = 27-MPH burning 12.2-GPH for 2.2-MPG

For the optional engines, 420-HP, the top speed should increase in proportion to (840/700)^0.5 = 1.095 or to 36-MPH. The fuel consumption would increase linearly by 1.12 to 48.6-GPH. This would give fuel economy at full-throttle of 0.75-MPG. At cruising speed the fuel consumption and fuel economy should be the same as with the smaller engines.

Can you "go to the bank" with these figures, well, perhaps not. They are estimates. But I expect they will be fairly close to real-world performance. Perhaps the cruising fuel economy is a bit optimistic.

dpa11111
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Re: Defiance

Postby dpa11111 » Thu Jul 25, 2019 3:41 pm

I own a 2001 Boston Whaler 34' Defiance made in Edgewood, Florida. I keep the 34 DEFIANCE in Destin, Florida. I use the 34 DEFIANCE most months at least some. The 34 DEFIANCE is a great boat, but, like all boats, has a few problems.

The layout of the cockpit is ideal for sport fishing. The cockpit has good storage for gear, lures, hardware in the cockpit forward bait-station prep area. It has a large bait well with pump and lights, and one refrigerated and one bait freezer accessible on deck. My 34 DEFIANCE has 21 rod holders, outriggers, downriggers, and numerous rod holders across the transom for trolling.

There are two large lockers, in the cockpit area, one for fish and the other for ropes, bumpers, anchors, etc.—a very good layout.

Beam is 13.5-feet—lots of room.

Draft is just under three feet.


The 34 DEFIANCE boat speed is about 37-MPH at engine speed of 3500 to 3600-RPM on Yanmar 6LY2STE engines.

I typically cruise about 25-MPH at 2600-TPM when the hull is clean and the propellers are true. This gets about1-MPG.

The interior cabin is acceptable for overnights on the Gulf of Mexico, but somewhat small for longer term use. It has a decent air conditioner for the cabin, a two-burner stove, microwave, refrigerator, shower, and vacuu-flush—a great fishing setup.

I had to adjust the rudder toe-in to get the 34 DEFIANCE to track straight and be more stable. The owner’s manual is available on a Boston Whaler web site. It gives the toe-in specs, and it is necessary to toe-in to get good tracking and stability at most speeds.

The 34 DEFIANCE is also VERY sensitive to the trim tabs, and if one is different than the other it will yaw dramatically. I now always reset my trim tabs before putting her on plane, as it can be dangerous not to. If your BW Defiance 34 doesn't track well, check rudders toe in and trim tabs reset (yp) locations are the same.


The hull shape is not exactly what I call a true deep V, so the 34 DEFIANCE tracks best in lower sea-states
and tends to wander in waves and chop more than a Carolina hull or sharper-V.

The 34 DEFIANCE hull is a design compromise—I assume—since Boston Whaler put the propellers in tunnels to reduce draft. The hull designer added a novel exhaust system that uses a hydrodynamic venturi to reduce engine backpressure at planing speeds to increase engine power and reduce exhaust noise, fumes, and residue.

My autopilot handles all these effects well, so no big complaint.

The 34 DEFIANCE is a wide and relatively short boat length, so yaw stability is less than some other boats in this range, but it is manageable, and offset by other advantages.

That underwater exhaust manifold (exhaust gas venturri in keel centerline at transom exit point) down under works pretty well, but [the diesel engines] run rich accelerating from a standing start to get on plane, and they produce black smoke during that transition. The Yanmar 6LY2STE engines have 420-HP peak power, and they are solid and light.

My boat was hit by lightning once, blowing all the Garmin electronics, but the engines were 100%.

The only drive train problem was blowing out three starboard engine exhaust manifold gaskets on the starboard engines. This was traced to a water leak above the engine (cup holders with drain holes not plumbed) that kept the gaskets wet after rain, and weakened the gasket accelerating failure. Gasket replacement was a four-hour fix, and back running again.

Also one great feature on this boat is the entire deck over the mid section of the boat is on a motorized slide, and moves back about one meter to allow engine access. That is a big relief when engine maintenance or other engine room work is needed. That was one of the reasons I bought the 34 DEFIANCE.

I previously had a Hatteras 53' and knew how important engine access is for good maintenance.

As a fishing machine, a 34 DEFIANCE is a great boat. My boat has a special low-speed-trolling capability that retards the transmission gearing to go extra slow, but I never use it, as one engine trolling at idle gets down to 4-MPH—that is slow enough.

I also don't use the Glendenning syncronizer, a nice feature I have had before, but with NMEA2000 gauges I added, and autopilot, it is an unnecessary complexity I don't use.

I love that the Captains chair is almost on centerline, making driving with good visibility easy. The other seating is also symmetric so boat loading and ride are good when passengers sit symmetrically around the boat cockpit and seating areas.

My 34 DEFIANCE weighs 20,000-lbs wet, so it is heavy enough yet light enough for Gulf of Mexico action in moderate sea states.

I love this 34 DEFIANCE and prefer it to all others in this category and size range. I love the diesel engines, that diesel doesn't burn, and the Boston Whaler build that makes a boat that wont sink, both good qualities for when your 100 miles off the coast.

Enjoy your boating, and I recommend this boat as a great option.

Boston Whaler Defiance 34.jpg
Boston Whaler Defiance 34.jpg (97.29 KiB) Viewed 15009 times

dpa11111
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Re: Defiance 34

Postby dpa11111 » Thu Jul 25, 2019 4:02 pm

Here is a picture of my DEFIANCE 34 underway and a picture of test data from Boston Whaler:

BW Defiance Cockpit.JPG
Fig. 1. Typical high speed trolling for Wahoo not using the outriggers
BW Defiance Cockpit.JPG (95.9 KiB) Viewed 15006 times


Boston Whaler 34 Defiance Performance Test.jpg
Fig. 2. A picture of text that has data about performance of the 34 DEFIANCE.
Boston Whaler 34 Defiance Performance Test.jpg (176.15 KiB) Viewed 15006 times

Tacky79
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Re: Defiance

Postby Tacky79 » Fri Jul 26, 2019 6:02 pm

This is an amazing site with a wealth of information. I continue to be impressed by the knowledge here!
2017 Boston Whaler Montauk 190 w/ 150 Merc/Fish Pkg/Bowrail delete/aft seating
1979 Boston Whaler Harpoon 5.2 sailboat with sails and a tiller :D

jimh
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Re: Defiance 34

Postby jimh » Sat Jul 27, 2019 12:11 pm

dpa11111 wrote:The owner’s manual is available on a Boston Whaler web site.


What is the URL for the 34 DEFIANCE owner’s manual said to be posted for download by Boston Whaler?

If an internet web resource is mentioned or alluded to, the URL to the resource should be provided.

Pat Burdette
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Re: Defiance 34

Postby Pat Burdette » Tue Aug 17, 2021 8:49 am

[GHMariner, the initiator of this thread, has] made a great choice buying a used DEFIANCE 34.

I have a 2000 Defiance 34 with 370-HP diesel YANMAR engines. The DEFIANCE 34 is the biggest little boat you will find.

I purchased mine in 2004 with about 400 hours on it. I paid about half of the new-boat price.

Due to some bad decisions on my part, the DEFIANCE 34 boat sat in my barn from 2010 to 2020 with both engines setting beside it. Finally, i found a small shop in Daytona Beach willing to take on a boat-in-a-box-type [reassembly] job.

I built a trailer specific to the DEFIANCE 34 boat; the trailer fits it and it alone.

I took the DEFIANCE 34 boat [on its trailer] to the Daytona Beach mechanic. For about one year he worked at putting it back together, and doing some upgrades, as well. He had it during the [2019 - 2020] pandemic. While there was a shutdown at the Boston Whaler and SeaRay shops, the guys that were out of work for a while were happy to be able to earn some money by working on my boat.

One of the guys had been with Whaler for 25 years, and said he did the startup on every Defiance. He tells me they only made about 25 of them.

This boat has always been a bit slow getting out of the water and throws a lot of black smoke while doing it. I added propane induction hoping to help the acceleration. The propane induction needs to tweaked a bit, but I believe it does help.

Since the boat hadn't been insured for ten years, my insurance company required a survey. It was a very detailed survey for about $700.

They [the insurance company or the surveyor] listed the current value at around $120,000—in line with what you see a DEFIANCE 34 used boat advertised for sale, if you can find one for sale. They [the insurance company or the surveyor] listed the "replacement value" at $730,000. I was a bit shocked at that, but realized that there is no other boat like this.

jimh
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Re: Defiance 34

Postby jimh » Tue Aug 17, 2021 5:14 pm

vze2gbs4 wrote:Only sixty-three [DEFIANCE 34 boats] were ever build. Boston Whaler halted production due to the high cost of building them and very few sales. The first hulls were built at the Edgewater plant, and the rest were built at the Sea Ray plant at Merrit Island by Boston Whaler personal, from what I understand.



Pat Burdette wrote:One of the guys had been with Whaler for 25 years, and said he did the startup on every Defiance. He tells me they only made about 25 of them..


There is a substantial conflict between the recent second-hand comment that only 25 DEFIANCE 34 boats were built and the earlier comment that 63 DEFIANCE 34 boats were built.

Since the DEFIANCE 34 boats were apparently built in two different locations, the more recent comment that only 25 were built might be in reference to the volume of production in that particular plant.

jimh
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Re: Defiance 34

Postby jimh » Wed Aug 18, 2021 8:10 am

The DEFIANCE 34 has been the topic of several prior discussions. Here are some links to those threads:

DEFIANCE 34 Steering
https://continuouswave.com/ubb/Forum8/HTML/004162.html

Sunk Boston Whaler 34 Defiance for sale in Miami
https://continuouswave.com/ubb/Forum1/HTML/022441.html
This discussion also mentions that the total number of hulls built was 63. This casts further doubt that the total number of hulls built was 25 as cited above.

CETACEA Page 39
Intracoastal Water Way Whalers

https://continuouswave.com/whaler/cetac ... age39.html

DEFIANCE 34 and 350 Defiance
https://continuouswave.com/ubb/Forum8/HTML/000563.html

I believe the DEFIANCE 34 was only marketed in the 2001 to 2002 era.