2001 DAUNTLESS 16 Struggles to Accelerate Onto Plane

[jsmith0072]

I recently bought a 2001 DAUNTLESS 16. Its original engine was a Mercury 90, and in 2019 the boat was re-powered an E-TEC 115-HP. The boat struggles to accelerate to planing speed.

I am new to boats like this.

Q1: what is the first step to be taken to improve the time needed to reach planing speed?

Q2: is an E-TEC 115-HP engine the wrong choice for a 2001 DAUNTLESS 16?

Q3: can the engine mounting height be adjusted by me?

Any help will be appreciated.

[Phil T]

This model has a notch in the keel so getting up on plane is a challenge.

You need to mount the engine as high as it will go.

Install a 4 blade prop with stern lifting properties.

Two options include:

13x15 PowerTech SCD4
13.75x17 Mercury TrophyPlus

If the battery is in the stern, relocate to the console.

Seat a passenger in the bow.

Accelerate from a start hard until you are up on plane then reduce throttle to cruising speed. This takes practice to do smoothly.

[jimh]

Q1: what is the first step to be taken to improve the time needed to reach planing speed?

You need to provide much more information about the boat's performance than just the remark that there is a "struggle" to reach planing speed.

Read this lengthy article:
Propeller Testing: What Data to Collect; How to Evaluate that Data
https://continuouswave.com/forum/viewto ... f=7&t=7196

Then collect all the data required as presented in that article, and post all of the data in a follow-up.

Q2: is an E-TEC 115-HP engine the wrong choice for a 2001 DAUNTLESS 16?

I cannot image a better engine choice. A two-stroke-power-cycle direct-injected four-cylinder modern 115-HP engine like the E-TEC is a perfect match for re-powering an older boat.

Further, the 2001 DAUNTLESS 16 has a maximum engine power rating of 115-HP. The minimum engine power rating for the boat to be able to accelerate to planing speed was just 50-HP. On this basis alone, I cannot imagine that the boat would exhibit any problem is accelerating onto plane with 115-HP, as long as the engine was operating properly, the propeller was suitable, and the throttle settings were appropriate.

Q3: can the engine mounting height be adjusted by me?

Altering the engine mounting height is only necessary if the existing engine mounting height is not favorable. Since you have not provided information on the engine mounting height, it is not yet appropriate to change the engine mounting height.

As for whether you you yourself can accomplish a change in engine mounting height, that depends entirely on your own skill and willingness to work on the boat. The weight involved with a four-cylinder engine is significant, and you probably do not have the proper lifting adaptor. It may be more appropriate for you to have the engine mounting height changed--if a change in engine mounting height turns out to be recommended--by a dealer.

I am new to boats like this.

Your unfamiliarity with 16-foot outboard-powered boats can certainly be a factor in the way the boat is operated and how the boat performs. For this reason, I recommend you provide much more information before you undertake any further steps to effect a remedy for the "struggle" to reach planing speeds.

The "struggle" may be due to many factors that can be simple to fix, such as a more appropriate propeller, better engine trim, better throttle settings.

[Jefecinco]

I owned a 1999 Dauntless 16 powered by a 115 HP FICHT engine. The FICHT was the predecessor to the E-Tech. My experience was similar to yours.

Based on recommendations on this forum I replaced the original 3 blade propeller with a 4 blade propeller and raised the engine mounting height. The improvement in performance was spectacular.

[GoldenDaze]

As Jim said, "I can not imagine a better choice" for the motor, which give you maximum power for that hull at a comparatively light weight. It is, at least, significantly lighter than my Mercury 115 4-stroke.

Assuming your engine is running correctly and producing the normal amount of power, there are a few things to think about to improve acceleration:

1. Lighten the load. I don't generally fill my fuel tank above 3/4. It's a 45-gallon tank, which is a lot of weight, and when cruising at 3-3.5 gal/hr having 30 gallons on board seems like plenty.

2. Install a lower-pitch prop, ideally with 4 blades. On my 160 Dauntless I went from a 16" pitch Vengeance (3-blade) to a 17" Trophy Plus (4-blade) to a 15" Spitfire X7 (also 4-blade). With each change, I gave up a little top speed for better acceleration and planing, and each change made me happier. The original top speed with the Vengeance was about 45 mph, and the Spitfire does 40-41. Since I rarely run the boat over 30 mph I really don't care. While the Vengeance would struggle to get the boat up on plane with 4 people and a full tank, the Spitfire pushes the boat up with ease. See

https://continuouswave.com/forum/viewtopic.php?t=7176

and

https://continuouswave.com/ubb/Forum4/HTML/004868.html

for more details. I don't know if these would be good propellers for you because I don't know your engine's lower unit gear ratio; mine is 2.07:1 with a maximum engine speed of 6,200 RPM.

3. Install a lower-unit hydrofoil. I used one for quite a few years and it was a help, but the next suggestion is better.

4. Install trim tabs. They are pure magic on this boat and well worth the cost and effort. For details see

https://continuouswave.com/forum/viewtopic.php?t=3860 for details.

-Bob

[ThePetrel]

Congrats on buying a great boat. I also have a 2001 Dauntless 16.

I've ordered trim tabs this winter and will try them out for the first time this spring.

Trim tabs are not cheap, as parts can easily cost $1,500 to $1,800 before labor, but from what I understand they will work very well on [a DAUNTLESS 16].

I bought the DAUNTLESS 16 in 2023 from a friend who upgraded to a larger OUTRAGE. He put trim tabs on the OUTRAGE and loves them. He told me, "I can't believe I never thought to put tabs on the DAUNTLESS 16. They would be admirable on that boat."

That was enough for me. I'll have my DAUNTLESS 16 back in the water (fingers crossed) this May. Contact me then if you want a first-hand account.

Lots of luck with your Boston Whaler DAUNTLESS 16, and enjoy the camaraderie of this helpful Boston Whaler community.

-Mike

[jimh]

I am going to comment on some of the comments and recommendations made so far with regard to how to improve the performance of the 2001 DAUNTLESS 16 with an Evinrude E-TEC 115-HP engine. The most influential comment in this discussion so far is from the owner of the boat, who has stated:

I am new to boats like this.

On that basis, I must suggest that actually taking all the steps suggested should be done with this in mind. Some of the "struggle" may just be due to unfamiliarity with "boats like this." At this point, we have heard nothing concrete about the boat's performance other that the new-owner feels the boat "struggles" to reach planing speed. That is all that is known.

Bob (GoldenDaze) has presented a list of actions to take, and given them in an order that makes a lot of sense. Start with something easy and not very expensive. Work through the options in the order presented.

For someone who is new to a 16-foot outboard boat with a 115-HP engine, adding the further complication in boat operation of trim tabs may not be a great idea. Badly adjusted trim tabs can induce their own problems. Trim tabs are just one more element that needs careful adjustment to get the best outcome. For a guy who seems to be new to outboard engine boats that can reach planing speeds, adding more complexity to the engine operation may not the best idea for his first step at a remedy.

This DAUNTLESS 16 is powered at the maximum rated power, 115-HP, far more than the 50-HP minimum power needed to reach plane. That the boat “struggles” to accelerate onto plane seems very unusual, and more information from the boat’s owner should be provided and considered before diagnosis of the problem will be possible. We are at day ten in this discussion and there has been no reply from the boat owner.

[Jefecinco]

We owned a Dauntless 16 for about ten years. It was powered by a 115 HP FICHT 2 stroke engine turning a four blade propeller. The engine was raised to the next to the highest mounting position [two-holes-up]. We found the Dauntless to be a very stable platform once on plane although it was sensitive to weight movement.

We never seriously considered adding trim tabs to the boat because they seemed unnecessary and because the installation process would have been extremely difficult due to the very limited working space under the aft deck.

[fno]

I too owned a Dauntless 160 for several years of Gulf fishing, waterskiing, etc. I had the Mercury 90 HP four stroke installed. It too labored to get on plane in most circumstances. Bob is spot on with his recommendations. In the end, I had two props depending on the use and a Doel-Fin which greatly enhanced the ability to get up on plane with either prop. A couple of questions: 1. Do you start out with the motor trimmed all the way down and keep it there until the boat is up on plane? Absolutely essential practice. What prop are you running? (Pitch, material, model) As Jimh said, we can offer plenty of advice, but it will be wide ranging and up to you to decide which advice applies the best. In other words, help us help you.

FWIW, Boston Whaler's assertation that the Dauntless 160 would operate and get on plane with any 50 HP motor is in my opinion a gross exaggeration. I would not expect that boat to get on plane with a 50 HP engine even if my 160 lb. Grandson was operating alone with a gallon or two of gas, no battery, and the cushions and cooler sitting on the dock.

[Todd]

I have a 2003 DAUNTLESS 16 with a Mercury 115-HP FourStroke. I often run with a full tank of fuel, Yeti 45 cooler full of beverages and ice—trust me, it weighs a ton—and four full-sized (no judgement) adults. The only time my boat has trouble planing is when their are weeds on the prop (my fault) or if the engine is tilted up to much (to avoid the weeds).

My only thought in addition to the other experts comments is if you don't have a Doel fin otherwise known as a "whale tail" try one. They are fairly inexpensive and easy to install (Amazon has one for $28). They also can be removed it you don't find it helpful. My boat came with one so I don't know how much difference it makes but I certainly believe it helps.

I've had larger boats with trim tabs (38' Sea Ray Sundancer most recently) and know they are effective for those applications but the comment about them adding one more thing you have to "fiddle" with it very true. My wife can attest to her annoyance with me constantly adjusting them to get the optimum planing speed for fuel efficiency (the 8.1L V8's in the Sundancer burned fuel at an alarming rate).

The good news is you have a very fine boat. It's the last boat I'll ever own and frankly, the best including the $400,000 Sea Ray.

Hope this helps.

Todd