2003 DAUNTLESS 160 Sea Trial

Optimizing the performance of Boston Whaler boats
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2003 DAUNTLESS 160 Sea Trial

Postby Miataman1963 » Mon Jul 08, 2019 8:44 pm

Hi everyone. I [may buy] a 160 DAUNTLESS. I went on a trial today. The 160 DAUNTLESS has a Mercury 90 two-stroke-power-cycle engine with low hours. It is a very clean boat. Here are my observations and what I need help with

There was a lot of vibration at trolling speed. I felt the vibration when holding onto the center console grab rail.

Q1: Is this normal?

With two 200-lbs guys behind the center console, half a tank of fuel, and a medium/sized woman in the jump seat, the 160 DAUNTLESS was slow to get on plane.

The engine has the standard aluminum propeller. I am unsure of the engine mounting height.

I know the 160 DAUNTLESS is slow to plane. The bow really went high, and to get the bow down took a while.

Q2: Any thoughts?

Q3: Hydrofoil? People sitting in bow will help?

At about 4800-RPM a GPS showed 26-MPH SOG.

Q4: Is this normal for this set up?

[The seller] said he had just a slight amount more [throttle opening] to go before wide-open.

Q5: Is this normal?

Q6: [What engine speed should be necessary to reach] 25-MPH?

I really like this boat but have nothing to compare it to.

My previous boat was a 2004 Montauk 170 wIth a 90 FOURSTROKE that was smooth as silk.

Q7: Any feed back?

Thanks. Alan

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Phil T
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Re: Sea trial on 2003 dauntless 160

Postby Phil T » Mon Jul 08, 2019 9:05 pm

Reads like:

Engine running on 2 cylinders or very bad prop selection/mounting height.

No such thing as "standard" aluminum prop.

This hull tends to have significant bow rise. Adding hydraulic tabs will solve it as will a 4 bladed prop.

Read these threads:

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1992 Outrage 17, 1992 Evinrude 115

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Re: Sea trial on 2003 dauntless 160

Postby Jefecinco » Tue Jul 09, 2019 10:47 am

Since you are shopping for a used boat you can't get much better than a 160 Dauntless or a Dauntless 16. We owned one for 10 years and it was a terrific boat in ever way.

Due to several factors the boats are stern heavy. For this reason I recommend you look at the used market for a 160 Dauntless with a 115 HP engine which was the maximum power for the 160s. Performance will be far superior.

On our boat we adjusted the engine mounting and installed a four blade stainless steel propeller and the performance was exceptional. We lost about two or three MPH from our top speed but were happy to do so as we very seldom operated at top speed. Trim tabs were not needed.

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Re: Sea trial on 2003 dauntless 160

Postby MillieTheBoat » Tue Jul 09, 2019 1:29 pm

I have a used 2003 Dauntless 160 with 115 HP I bought in 2015. I use it primarily for cruising, and fishing between Dana Point and Newport Beach Harbor, CA with the family. I take her out only when the wave is between 2-5 foot. I am still new with boating and this is my first boat and it is a solid one. It barely fits in my garage with only 2 inches left on the side walls parked diagonally . It seems like a big boat for a 16 footer. Butch, Bob, and others have more experiences with this boat and there are articles on here to do some additional modifications.

Last week, I replaced the original Teleflex steering system with a Baystar Hydraulic steering system. Bob (GoldenDaze) has a wonderful write up on this subject. Back in 2015, I added an additional battery and an On/Off switch. Next year, I am planning to add trim tabs since the boat is heavy at the back. For my immediate quick fix before installing the trim tabs, I added a second set up mushroom anchor on the front storage area. Also, I replaced the original propeller with the Trophy Plus and it makes a big difference.

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Re: 2003 DAUNTLESS 160 Sea Trial

Postby B.E.Coyote » Tue Jul 09, 2019 4:26 pm

Here is what I just went through to get my new to me 2000 Dauntless 160 set up well.


In short the answer was Bennett Bolt electric trim tabs. I love the boat now.

What you describe with 3 aboard and an aluminum prop of unknown size and pitch sounds about right.
2001 Dauntless 160
Virginia Beach

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Re: 2003 DAUNTLESS 160 Sea Trial

Postby jimh » Wed Jul 10, 2019 7:43 am

A7: Don’t buy a boat if you are not thrilled with the performance.

The seller’s reluctance to demonstrate the boat at wide-open-throttle speed was odd. Did the sea state prevent going to full speed?

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Re: 2003 DAUNTLESS 160 Sea Trial

Postby Lupi » Thu Jul 11, 2019 5:24 am

I currently own a Dauntless 16 with the old 90 mercury 2 stroke carb. The stock prop for this engine was the Aluminium Black Max 13*19. Top speed for this set up was 39,3 mph @ WOT (5500 rpm) (numbers from BW). I attach here the perf data sheet I could grab from BW. You'll get then all speed data from idle to WOT for all configurations of engines (90 and 115, 4S, 2S and optimax). Your motor in the list is the 90 classic.

Overall performances with stock prop are not very good. The boat is very low to get on plane and sometimes very very very low (when pulling skier). Idle speed hard to maintain,....

I changed the stock ptop by a SS prop (Stiletto 131/4*17) and raised the motor 2 holes more to be at 3 holes up. In addition, to add weight on the bow, I put a heavy anchor. With this set up, overall performances were significantly improved. Idle speed, hole shot,..) Top speed remained unchanged compared to stock prop, but you cannot do miracle with 90 hp on this boat. This engine is good, nervous with plenty of power and, it is light, lighter than most of the current range of 90 hp (2 and 4 strokes) that is important here for this boat. However, I consider that this boat is underpowered with 90. Most of the people here who own / have owned this boat report much better performances with 115 hp. Many threads are covering the dauntless 16/160. You will certainly find many answers about various settings that can be made to optimize performances.

160Dauntless perf sheet data 2.pdf
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Re: 2003 DAUNTLESS 160 Sea Trial

Postby GoldenDaze » Thu Jul 11, 2019 10:50 pm

The 160 Dauntless is a great little boat, I've had mine for 16 years. I think that 90 HP is marginal, but at least the classic 90 2-stroke has more torque than the 90 4-stroke which I really wouldn't recommend. As Phil and others mentioned, trim tabs make a huge difference on this boat. It is a bit stern-heavy, perhaps somewhat less so with the lighter 90 2-stroke. I recommend not running with a full tank of fuel unless you're planning to need it.

There have been many reports of the boat running 38-39 MPH with 90 HP, as compared to 42-44 with 115 HP. To me the difference in power is less about top speed as conditions need to be ideal to run that speed in a small boat, and more about having a little more oomph to get on plane. Running 26 MPH at 4800 RPM seems way off, I'd think you'd be more like 3600-3800 RPM. Either the prop is really trashed, or it's very under-pitched (in fact what you're seeing is pretty close to what I get running a 13" Black Max aluminum prop instead of my 17" Trophy Plus stainless prop), or the engine isn't delivering full power.

I think you have some more investigation to do before signing on the dotted line for this boat, unless you were planning to replace the motor anyway.

2003 160 Dauntless Golden Daze