160 Dauntless Notched Hull Porpoising - Moderated Discussion Areas

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Performance
  160 Dauntless Notched Hull Porpoising

search | FAQ | profile | register | author help

Author Topic:   160 Dauntless Notched Hull Porpoising

buddha posted 02-19-2009 02:23 PM ET (US)
I am in the process of searching for a used 160 Dauntless with a 115-HP four-cycle motor, and I have read many discussions about the notched hull prior to 2002. I contacted customer service at Boston Whaler and asked about the excessive porpoising due to the notched hull. They felt that I would not notice the performance difference, and that [the notch in the hull] was only designed to assist in initial plaining. Please share any first-hand experience with this. If there is a noticeable difference on the un-notched hull then I will definitely be looking for a 2002-model year or newer. Thank you!
Jefecinco posted 02-19-2009 06:45 PM ET (US)
I have a notched hull 1999 Dauntless 16. It has no propensity to porpoise. I have been able to induce porpoising only by trimming the engine out farther than 50% when conditions are slightly lumpy. I've found that trimming out beyond 50% in absolutely flat water provides no performance enhancement.
If you buy a 16 Dauntless I recommend you get the 115-HP engine vs a 90-HP motor.
Butch
jimh posted 02-20-2009 09:25 AM ET (US)
For readers who are not acutely aware of the difference, please describe in more detail the notched-hull model compared to the later model.
buddha posted 02-20-2009 03:43 PM ET (US)
The 160 dauntless's produced before 2002 had a small portion of the "v" hull notched or cut away at the back of the boat to allow for better water flow around the prop for faster planing. On the 02' and later models the notched portion was removed and filled with foam. I am currently looking at a couple of 01' models with 115 four strokes. Again anyone with any valuable information on this subject is greatly appreciated!
Thanks again!!!
Marlin posted 02-20-2009 07:05 PM ET (US)
I have a 2003 boat with a 115, no transom notch. It's a great boat, though unlike Butch I find that it really does like to porpoise quite a bit unless you trim it very carefully. With or without a notch, you're going to want a hydrofoil to help keep the bow down. With the foil, if you find a nice pre-2002 boat, go for it. It's absolutely the very biggest 16-foot boat around.
-Bob
Jefecinco posted 02-20-2009 07:22 PM ET (US)
Marlin,
I've done three things to my boat/engine setup since buying: Added a hydrofoil which made little difference, changed from a three blade to a four blade propeller, raised the engine mounting by one hole.
My [problem] was very poor [accelerating from a standing start] and my efforts were to improve it. I never had a porpoising [problem] but my engine is a two stroke cycle FICHT. Also, my boat is usually very heavily loaded. I now enjoy incredibly good [accelerating from a standing start] and the boat leaps onto plane almost immediately. My top speed is down slightly but the improved performance, to me, is well worth it.
To improve your [accelerating from a standing start] I recommend experimenting with engine mounting height. If that does not improve things to your satisfaction some propeller experimentation may do the job.
Butch
Marlin posted 02-21-2009 10:17 AM ET (US)
Thanks for the suggestions, Butch. I've done basically the same thing over the years. I'm currently running a 4-blade Trophy Plus prop in 17" pitch. I don't recall right now which hole the engine is mounted in, but I ended up 1 hole up from the delivery setup. I tried 2 holes up, but I got too much ventilation.
Oddly, at least as compared to your comment, I found that the foil made the largest single difference by far in the boat's performance. It helped to plane much faster, stay on plane several miles/hour slower (which is very nice when it's choppy), and just generally help keep the bow down. Up above about 4000 RPM, the foil is mostly out of the water and irrelevant.
I have the Mercury 115 4-stroke, which is probably heavier than your engine by 100 pounds or more, so that might be part of the difference.
-Bob
Jefecinco posted 02-22-2009 10:18 AM ET (US)
Bob,
Interesting. The basic differences between our boats is engine weight and hull notch. Although we run different propellers they are both four blade. Despite the similarities we have quite different running characteristics. It just goes to show that small changes can make large differences in running caracteristics.
Loading could be the main difference. I usually have three well equipped angles, a cooler with 10 pounds of ice, three heavy tackle boxes, Three lunch coolers, two anchors one of which is a twenty pound mud anchor, an emergency jump battery, and a fuel tank at least half full. Of course a spare rode, mooring lines, first aid kit, and all CG required equipment, My largest guest gets to ride on the cooler as he goes about 230 pounds. My other guest and I go about 180 each.
The hydrofoil was my first modification. It was a help but I tend to minimize the effect because the propeller change and engine height adjustment produced such spectacular results. Pre hydrofoil both guests had to be forward of the console to get on plane in any kind of resonable time. After the hydrofoil only my heavy guy had to be forward.
I keep meaning to femove the hydrofoil to see if it changes anything. I expect any change to be minimal but I'm ready to be surprised.
Butch
lefty93 posted 02-22-2009 12:59 PM ET (US)
I have an 02 Dauntless 160 with the 90hp 4 stroke. I msde the same changes Bob has made. Added a hydrofoil, moved the motor up one notch, and added a Trophy Plus 17 pitch prop. All have made a difference and I find little or no proposing now and good acceleration, even with the 90hp. I can pull my 28 year old son up on his wake board just fine and he can get me up on water skis as well. It really is a great boat and big for 16 feet. Even though I wish at times I had the 115 hp, I haven't found the 90 hp to be much of a handicap.
Bob, I would be interested to know which size vent hole plug you are using in your Trophy Plus. Thanks for the good information and discussion
Don
Marlin posted 02-22-2009 03:38 PM ET (US)
I'm using medium vent plugs in the Trophy Plus, honestly by default. I've also tried it with the plugs out, but the prop ventilation was really excessive, and the boat couldn't get out of its own way. The medium plugs do seem to do a good job of letting the engine wind up into its power band. See my analysis of my 3 props at http://continuouswave.com/ubb/Forum4/HTML/004868.html
-Bob
lefty93 posted 02-22-2009 08:30 PM ET (US)
Thanks, Bob, for your response. I'll look at your analysis of your 3 props.
Don
skred posted 02-23-2009 02:13 PM ET (US)
Here's a couple views of my former 2002 D16's "notch":
http://s216.photobucket.com/albums/cc217/skred/?action=view& current=SternViewjpg.jpg
http://s216.photobucket.com/albums/cc217/skred/?action=view& current=P1010007.jpg
skred posted 02-23-2009 02:15 PM ET (US)
Oh, yeah - forgot: with the foil - no porpoising and time-to--plane time very low.
whaler1414 posted 02-23-2009 04:47 PM ET (US)
[Use MARKETPLACE for this sort of article.--jimh]
buddha posted 02-24-2009 04:47 PM ET (US)
Thanks everyone for all your info and for the great pics!!!
att. (skred) what horsepower are you running, I can tell it's a Honda four stroke but can't see size?
Also what is your top speed if you don't mind?
Thanks
Buddha
skred posted 02-26-2009 10:01 AM ET (US)
My Honda was a 90 carbureted model. Top GPS speed was 38-42 depending on load.

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: 160 Dauntless Notched Hull Porpoising
buddha	posted 02-19-2009 02:23 PM ET (US) I am in the process of searching for a used 160 Dauntless with a 115-HP four-cycle motor, and I have read many discussions about the notched hull prior to 2002. I contacted customer service at Boston Whaler and asked about the excessive porpoising due to the notched hull. They felt that I would not notice the performance difference, and that [the notch in the hull] was only designed to assist in initial plaining. Please share any first-hand experience with this. If there is a noticeable difference on the un-notched hull then I will definitely be looking for a 2002-model year or newer. Thank you!
Jefecinco	posted 02-19-2009 06:45 PM ET (US) I have a notched hull 1999 Dauntless 16. It has no propensity to porpoise. I have been able to induce porpoising only by trimming the engine out farther than 50% when conditions are slightly lumpy. I've found that trimming out beyond 50% in absolutely flat water provides no performance enhancement. If you buy a 16 Dauntless I recommend you get the 115-HP engine vs a 90-HP motor. Butch
jimh	posted 02-20-2009 09:25 AM ET (US) For readers who are not acutely aware of the difference, please describe in more detail the notched-hull model compared to the later model.
buddha	posted 02-20-2009 03:43 PM ET (US) The 160 dauntless's produced before 2002 had a small portion of the "v" hull notched or cut away at the back of the boat to allow for better water flow around the prop for faster planing. On the 02' and later models the notched portion was removed and filled with foam. I am currently looking at a couple of 01' models with 115 four strokes. Again anyone with any valuable information on this subject is greatly appreciated! Thanks again!!!
Marlin	posted 02-20-2009 07:05 PM ET (US) I have a 2003 boat with a 115, no transom notch. It's a great boat, though unlike Butch I find that it really does like to porpoise quite a bit unless you trim it very carefully. With or without a notch, you're going to want a hydrofoil to help keep the bow down. With the foil, if you find a nice pre-2002 boat, go for it. It's absolutely the very biggest 16-foot boat around. -Bob
Jefecinco	posted 02-20-2009 07:22 PM ET (US) Marlin, I've done three things to my boat/engine setup since buying: Added a hydrofoil which made little difference, changed from a three blade to a four blade propeller, raised the engine mounting by one hole. My [problem] was very poor [accelerating from a standing start] and my efforts were to improve it. I never had a porpoising [problem] but my engine is a two stroke cycle FICHT. Also, my boat is usually very heavily loaded. I now enjoy incredibly good [accelerating from a standing start] and the boat leaps onto plane almost immediately. My top speed is down slightly but the improved performance, to me, is well worth it. To improve your [accelerating from a standing start] I recommend experimenting with engine mounting height. If that does not improve things to your satisfaction some propeller experimentation may do the job. Butch
Marlin	posted 02-21-2009 10:17 AM ET (US) Thanks for the suggestions, Butch. I've done basically the same thing over the years. I'm currently running a 4-blade Trophy Plus prop in 17" pitch. I don't recall right now which hole the engine is mounted in, but I ended up 1 hole up from the delivery setup. I tried 2 holes up, but I got too much ventilation. Oddly, at least as compared to your comment, I found that the foil made the largest single difference by far in the boat's performance. It helped to plane much faster, stay on plane several miles/hour slower (which is very nice when it's choppy), and just generally help keep the bow down. Up above about 4000 RPM, the foil is mostly out of the water and irrelevant. I have the Mercury 115 4-stroke, which is probably heavier than your engine by 100 pounds or more, so that might be part of the difference. -Bob
Jefecinco	posted 02-22-2009 10:18 AM ET (US) Bob, Interesting. The basic differences between our boats is engine weight and hull notch. Although we run different propellers they are both four blade. Despite the similarities we have quite different running characteristics. It just goes to show that small changes can make large differences in running caracteristics. Loading could be the main difference. I usually have three well equipped angles, a cooler with 10 pounds of ice, three heavy tackle boxes, Three lunch coolers, two anchors one of which is a twenty pound mud anchor, an emergency jump battery, and a fuel tank at least half full. Of course a spare rode, mooring lines, first aid kit, and all CG required equipment, My largest guest gets to ride on the cooler as he goes about 230 pounds. My other guest and I go about 180 each. The hydrofoil was my first modification. It was a help but I tend to minimize the effect because the propeller change and engine height adjustment produced such spectacular results. Pre hydrofoil both guests had to be forward of the console to get on plane in any kind of resonable time. After the hydrofoil only my heavy guy had to be forward. I keep meaning to femove the hydrofoil to see if it changes anything. I expect any change to be minimal but I'm ready to be surprised. Butch
lefty93	posted 02-22-2009 12:59 PM ET (US) I have an 02 Dauntless 160 with the 90hp 4 stroke. I msde the same changes Bob has made. Added a hydrofoil, moved the motor up one notch, and added a Trophy Plus 17 pitch prop. All have made a difference and I find little or no proposing now and good acceleration, even with the 90hp. I can pull my 28 year old son up on his wake board just fine and he can get me up on water skis as well. It really is a great boat and big for 16 feet. Even though I wish at times I had the 115 hp, I haven't found the 90 hp to be much of a handicap. Bob, I would be interested to know which size vent hole plug you are using in your Trophy Plus. Thanks for the good information and discussion Don
Marlin	posted 02-22-2009 03:38 PM ET (US) I'm using medium vent plugs in the Trophy Plus, honestly by default. I've also tried it with the plugs out, but the prop ventilation was really excessive, and the boat couldn't get out of its own way. The medium plugs do seem to do a good job of letting the engine wind up into its power band. See my analysis of my 3 props at http://continuouswave.com/ubb/Forum4/HTML/004868.html -Bob
lefty93	posted 02-22-2009 08:30 PM ET (US) Thanks, Bob, for your response. I'll look at your analysis of your 3 props. Don
skred	posted 02-23-2009 02:13 PM ET (US) Here's a couple views of my former 2002 D16's "notch": http://s216.photobucket.com/albums/cc217/skred/?action=view& current=SternViewjpg.jpg http://s216.photobucket.com/albums/cc217/skred/?action=view& current=P1010007.jpg
skred	posted 02-23-2009 02:15 PM ET (US) Oh, yeah - forgot: with the foil - no porpoising and time-to--plane time very low.
whaler1414	posted 02-23-2009 04:47 PM ET (US) [Use MARKETPLACE for this sort of article.--jimh]
buddha	posted 02-24-2009 04:47 PM ET (US) Thanks everyone for all your info and for the great pics!!! att. (skred) what horsepower are you running, I can tell it's a Honda four stroke but can't see size? Also what is your top speed if you don't mind? Thanks Buddha
skred	posted 02-26-2009 10:01 AM ET (US) My Honda was a 90 carbureted model. Top GPS speed was 38-42 depending on load.