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2 days ago I joined the BW cult by purchasing a 1996 15' Dauntless powered by a 2003 40 HP 4-stroke Merc. I test drove the boat before I got it with 3 people on board-then 2 and still had trouble getting out of the hole. I knew the boat was somewhat underpowered but I wanted a BW and after shopping for 2 mths I couldn't have gotten a better deal. The motor literally has 30 hours on it and repowering is not an option. After reading a lot of posts I have pretty much decided on Nauticus Smart tabs. Additionally I'd like to replace the prop. I don't know for sure but I believe the current prop came standard on the motor as a Mercury Black Max aluminum prop. My primary purpose for the boat is simply for getting from point A to B. After much research my head hurts and I still don't understand the pitch/prop science but I believe I'll have to sacrifice some top-end speed for hole torque.

I would greatly appreciate an opinion on the smart-tabs and more importantly a new prop. Thanks...

DQ

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You need to run the boat lightly loaded at full throttle and make note of your rpm's and speed via GPS. Also look at the hub on the prop and find the mark for pitch or model number. Once there is a baseline of the current props performance then someone can make a recommendation for the best prop.

I can say my Dauntless 15 is powered by a 75 mercury 2 stroke and I wish I had a 90. With a 40 4 stroke you will barely have enough power to plane.

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Hello GW1996 and congrat's on the Dauntless purchase.

Your 40 4-stroke Merc is definitely on the lower end of rated HP for the Dauntless 15 but, it will do what you require...getting from point A to B. Verify what prop are you currently spinning and research what is recommended for that motor and if a Stainless prop is possible.

Motor height on the transom is also important, less drag if the cavitation plate is just above the keel. The Merc has power trim...correct? I would postpone adding trim tabs just yet until you research a proper prop and out board transom height.

The Dauntless 15 does not have any substrate (wood or otherwise) within the transom area for attaching a trim tab assembly. I purchased my Dauntless with trim tabs and they were poorly installed requiring some creative engineering on my part to correct the problem (see my project album).

I've done a few improvements to my Dauntless for my benefit and boating pleasure, their great little whalers and tons of fun for running the bay here in So. Fla.

Best regards,
Angel M.

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I'll be working on the Dauntless out of the water for another week or so and then I'll water test it to gauge speed and RPMs. The number on the current prop is 48-73136-13. In a separate box just in front of the number it has the letter "L". I'm not sure what all this means...

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Does anyone else have any comments regarding Angel's post on the Smart Tabs not working on the Dauntless because of the foam core?

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I installed smart tabs on both my 1986 13 foot sport and now my 1995 dauntless with great results. Angel is absolutely correct about no substrate on the lower transom, however, I believe that area is probably the thickest part of the fiberglass on the boat as it has all the stress of the motor trying to pull the transom off the back of the boat. When I installed my smart tabs, I purposely under drilled the pilot holes and then slowly sized them up to a pretty snug fit. Start drilling the pilot holes in forward just enough to start a hole that will keep the drill from skipping around and then drill a little bit in reverse, then finish in forward. This will keep the surrounding gel coat from chipping. Then mount the tabs using 3M 5200 in the screw holes. This method has worked well for me on both boats and I have had no issues. The results of having the tabs on both my 13 and 15 foot hulls were like night and day. Both boats have little to no bow rise, jump up on plain quickly, and maintain plane at slow speeds which is important if you are battling rough water like we experience here on the great lakes. Another pointer I would give is if you do decide to get the smart tabs, buy the stainless steel model. I have had both the plastic and SS and the plastic will stain up if the boat is left in the water and the stainless will come clean with a good pressure washing.

Jim G.

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I had BOE Marine Install smart tabs on my Dauntless 15. The only issue with the install was the port side boarding platform. They had to cut a notch out of the underside to properly attach the actuator ram. They just used stainless screws and plenty of 5200 to attach them.

They have been installed for a year and a half and are sturdy as can be. I'm very happy with the 30# actuators and how the tabs preform.

As was said earlier though, get the proper motor height , and propeller first. Then you can decide on the tabs.

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I just had an expert look at the positioning of the motor-he agrees it is in the optimal position with the pressure plate level with the bottom of the keel.

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Not to second guess your expert but my motor is in the highest position with the anti ventilation plate 1" above the keel. The Dauntless 15 is very sensitive to motor height. When my motor was lower and even with the keel it didn't run well at all. Kinda apples and oranges though since we have different power. Typically though, the anti ventilation plate should be slightly higher than the keel.

Might be worth a try raising it a little bit. You can always move it back down if performance drops. It's not a major deal to raise and lower the motor on this boat.

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Also regarding the prop, it's a mercury black max 10&3/8 x 13" propeller.

That's the stock prop with your motor but coupled with an 850# Dauntless 15 it may be too steep. Long term it likely will lug the motor and shorten its life.

Short term, it would be best to get real number with the current setup before changing props. Keep in mind every 1# of pitch up or down will change the rpm's by about 200 respectively.

I still would. Try raising the motor as high as possible while still maintaining good traction. This will reduce drag and give you more rpm's and speed.

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That really doesn't tell us much.
Where is the motor mounted according to bolt holes?
http://www.whalercentral.com/articles...cle_id=106

Many Whaler experts here can tell you the optimum height for a given brand of motor without measuring at all.
Measuring is old school and for new boats that are still in the experimental stage.

Dauntless 15'
Yamaha = ? holes up
Mercury = ? holes up
etc.

Much better then measuring as very few people would measure this the same.

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DQ, many "experts" get this wrong. After experimentation, most people here have found that with a good prop, they can raise the motor and get better overall performance. A good starting point is to have the antiventilation plate around an inch above the keel. If you think about it, that makes sense - since the water coming off the keel is going to "fill in the hole" left by the boat's passage, the water level will have raised a bit by the time it gets to the motor.

Proper mounting height will reduce time to plane, steering effort, and bow rise on takeoff, and increase top speed and the effect of trim adjustments - all good things. Blaster's experience on the exact same boat is the most pertinent - there's nothing better than that. Raise it up! It's easy to do yourself if you're handy, and the boat is on a trailer.

in terms of trying things:

1) get a baseline measurement of speed and RPM, running light
2) raise the motor and retest
3) get a new prop and retest
4) try trim tabs

That is in increasing order of difficulty and cost. Trim tabs will only be needed if you can't get satisfactory performance otherwise - but save that for last as once you drill into the transom, you're stuck with them.

Tim

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Blaster has a Mercury 75hp and doesn't tell us what year it is.

GW has a 2004 Mercury 40hp

The two motors may need to be mounted in different holes due to many factors that may include different gear cases, hp, prop, etc.

Would be much better to compare with someone else who also has a 40hp Mercury.

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You need to find a new "expert" since the feature of the lower unit that is important is the anti-cavitation plate.

Additionally, for a Boston Whaler hull, the member recommended optimum position for the motor is to have the anti-cavitation plate 1 1/2 -2 inches above the keel. There are two exceptions.

Exception 1 - E-TEC motors should be mounted all the way up.

Exception 2 - Some propellers require a lower or higher setup depending on blade material and design.

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Joe, to clarify, I was seconding blaster's recommendation of having the AV plate 1" above the keel. That takes other things (motor shaft length, where the holes are drilled) out of the equation.

I stand by my recommendation to try the cheap stuff first.

Tim

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To clarify, my motor is a 1996 Mercury 75 elpto. As I said, apples and oranges. As you stated, possibly different gear case.

As far as my comments to the exact mounting height, the motor is mounted in the lowest bolt holes. I didn't count t them as per your informative link. The 1" was just an eyeball and as you said subjective as compared to mounting holes. I can say the propeller hooks up strong throughout the powerband. (13x19" Solas)

While on plane the AV plate is above the water but the prop grips well.

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Just to clarify there are 5 mounting holes for the motor-it is secured on the 2nd hole from the top.

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That's great - so you'll have plenty of room to move up! Grab that baseline speed and RPM reading, and if you have the owner's manual for the motor it would also be great to know the recommended WOT RPM range.

Tim

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Hello GW1996 and just to clarify my input, I didn't advise against the "smart tabs" as many members here have had great success with them.

My comment focused on the transom installation of any trim tab type and the Dauntless 15 transom design. I failed to mention clearance issues with the swim/boarding platform if your Dauntless is so equipped, I had to modify mine to better accommodate the port side hydraulic ram of my Bennett tabs.

If and when you decide to install tabs and as jgortva suggested, lay-out all hole locations and drill very carefully. If mounting hardware is/are #10 screws and you damage one or more during actual install, you will need to remedy the situation and not simply rely on the sealant (5200) to secure the fastener.

Good luck with your prop search and performance test.
Angel M.

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The last thread is now locked so I am replying on this old thread which I should have done anyway. To answer some of the questions asked on the locked thread:

The boat maxed out at 29 with 2 people AFTER it was on plane. Prior to the Smart Tab installation in wouldn't plane unless someone moved forward.

I carry 8 gallons of gas in the stern.

The batteries are located in the console.

I'm not sure as to the diameter of the prop but the number on it is 48-73136-13

Further....I'm thinking i may indeed have a tach malfunction and will try to get one tomorrow. It idles at 1000 and has started to bounce around. I called Mercury about the largest size prop I could get on the motor and they told me "a little over 12". Then they told me that particular motor Merc 40 HP 4S EFI had an expired voltage regulator recall on it....$200. Just 4 grins I asked them what prop they'd put on that motor and they told me a 4 blade spitfire. Back to the drawing board. I'll get my tach and do the sea trials again. Stay tuned. Below was info on the locked thread.

Before Smart Tab Install

With just me in the boat it would plane in 7 seconds and turn 6100 RPMs WOT. It idles at 1000. Top end trimmed out was 30 MPH.
With 2 guys at 460 aboard it wouldn't plane at all hit 29 MPH and 5100 RPMs.

After install

With me in the boat it planed in 5 seconds and hit 5800 RPMs at 29 MPH.
With me and my buddy in the boat we planed in 12 seconds hit 5100 RPMs and topped at 26.

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It's in post #12 above http://www.whalercentral.com/forum/vi...ost_143414

You are talking about 3 or 4 separate items:

1. prop
2. smart tabs
3. tach
4. performance.

Don't. Too many interconnected items. You should handle one at a time and not start the next till its finished.

1. Diagnose and solve tach problem.
2. Re-test boat with existing prop with light load/heavy load.
3. Verify motor mounting position is correct. Change and redo #2.
4. Select a decent stainless steel prop.

P.S. No one really cares about precise time to plane. If you push the throttle to WOT, boat should pop up quickly if lightly loaded and much longer if loaded.

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Hello GW1996 and a couple of inquiries, why 2 batteries and why is your fuel tank (8 gals.) at the stern?

Your Dauntless being the same year as mine should have fuel tank storage within your helm seat housing. Their is a small 1 inch diameter deck hole which enters the rigging tunnel for running your fuel line aft to your outboard.

Your 8 gallons at the stern are adding roughly over 50 more pounds to your Dauntless 15. It may seem as insignificant weight but balancing your load on deck helps.

Best,
Angel M.

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Sorry to revive an old thread, but are you saying on a 15' SS (84') the E-TECs should be mounted higher? IE, 2" above the keel is okay? Having trouble gauging where I should drill the bottom holes to ensure I have it right.

Thanks Phil

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For re-drilling, review this article.

http://www.whalercentral.com/articles...icle_id=82

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Redrilling I get, I but I was wondering on the keel level on the ETECs. I have heard 1" above, but it looks like with my 60HO, its going to be 2" up off the keep to make the drill holes line up. Your quote was saying ETECs all the way up which was what I was curious about.
Thanks Phil