User Tag List

Page 4 of 7 FirstFirst 1 2 3 4 5 6 7 LastLast
Results 46 to 60 of 92
  1. #46
    Join Date
    Dec 2013
    Location
    Columbus Ohio
    Posts
    82
    Thanks (Given)
    8
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    ​Yes I was going to do that next. I looked at his site you can tell he is very intelligent. Going to try him today. Thanks
    Quote Originally Posted by Dave Strong View Post
    Static CG is at rest, Dynamic CG is more important, changes with speed, engine height, air and hydrodynamic drag, and many other factors. You need to get a copy of Jim Russell's Tunnel Boat Design Program, or at least talk witb Jim he may have helped someone else in the past with your hull.

    Dave

  2. Likes Dave Strong liked this post
  3. #47
    Join Date
    Apr 2001
    Location
    Ontario, Canada
    Posts
    801
    Thanks (Given)
    101
    Thanks (Received)
    33
    Likes (Given)
    812
    Likes (Received)
    157
    Mentioned
    1 Post(s)
    Tagged
    3 Thread(s)
    Quote Originally Posted by jmess13 View Post
    My friend has a 1990 eliminator scorpion with a freshly built 260 Mercury that is putting out an estimated 300hp. We have tried a wide variety of props 3 blade 4 blade anywhere from 25-30 pitch and we have played with the jack plate and engine setback. We can’t get the speeds or RPMs we are looking for. When I trim the engine to get the boat out of the water to try to make some RPMs the boat porpoises horribly. I had one lucky run one day where I caught a little bit of air under the boat along with a little chop on the water where the boat ran perfect and I saw 85 mph. I could never get it to do it again. The boat feels heavy or under powered to me. I was wondering if anyone has any experience with a similar set up and has any kind of recommendations of what we can try? Possibly a five blade prop?
    Quote Originally Posted by fasteddies69 View Post
    I think it makes 275ish. rev limiter is set at 8250 but we can't get more than 6800 to 7000 out of it. I weighed the boat and tandem axle trailer Weighed 2800 lbs. I think the trailer is about 900 lbs if I remember right Your boat looks great I have seen it before.
    jmess13/Ed – It was good to talk to you today, Ed. Your eliminator scorpion boat is a great project!

    I had a view of your video that you sent to me (https://youtu.be/eM_GNgjQCRs). I see the porpoising clearly. Good video. If this video is showing your current top speed with your 260hp engine, there is way too much wetted hull surface in the water. This boat should be capable of 80+mph. This hull design was developed originally as a jet drive, converted to outboard. Bare hull weight of 1300lbs is heavy. While the hull is susceptible to porpoising, starting around 50mph, you should be seeing more performance differences with changes in engine height and/or propeller changes. Perhaps your engine is not seeing full max hp or RPM? Is your engine mounted too low?

    I sent to you by email, a copy of an article that I wrote recently on “Porpoising” and what can be done about it. See if this is of some interest to you.

    Call any time to discuss.

    /Jim
    Last edited by Jimboat; 01-09-2021 at 08:17 AM.

  4. Likes Dave Strong liked this post
  5. #48
    Join Date
    May 2013
    Location
    Huntiington Beach Ca
    Posts
    971
    Thanks (Given)
    137
    Thanks (Received)
    134
    Likes (Given)
    1401
    Likes (Received)
    638
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fasteddies69 View Post
    Some new information. Boat weight is 1900 lbs. weighed it today without me a 200 lb driver. Boat weight says it is 1300 lbs dry, add fuel, battier, pumps, jack plate and engine it looks about right.

    Center of gravity with 11" set back is at 4'. Put the 16" set back plates on it and only moved center of gravity back 6" to 3'6". Engine was and is set so jack plate will move from 2" below the bottom of the boat to 2" above the bottom of the boat. the bottom of the boat looks flat had a 6' level and shows no hook at the back of the boat ( if I'm saying it right.)
    It is hanging in the air if there is anything else I might look at?

    Thanks Ed
    Did you get any pictures of the bottom of your hull and can you post.
    Can you measure the tunnels. Width and height. Entry, next to driver and rear.
    Be interesting to see how these numbers compare to say a 20 Stoker, 19 Laveycraft and a HST.

  6. #49
    Join Date
    Apr 2001
    Location
    Ontario, Canada
    Posts
    801
    Thanks (Given)
    101
    Thanks (Received)
    33
    Likes (Given)
    812
    Likes (Received)
    157
    Mentioned
    1 Post(s)
    Tagged
    3 Thread(s)
    Quote Originally Posted by fasteddies69 View Post
    Some new information. Boat weight is 1900 lbs. weighed it today without me a 200 lb driver. Boat weight says it is 1300 lbs dry, add fuel, battier, pumps, jack plate and engine it looks about right. Center of gravity with 11" set back is at 4'. Put the 16" set back plates on it and only moved center of gravity back 6" to 3'6". Engine was and is set so jack plate will move from 2" below the bottom of the boat to 2" above the bottom of the boat. the bottom of the boat looks flat had a 6' level and shows no hook at the back of the boat ( if I'm saying it right.) It is hanging in the air if there is anything else I might look at?

    Ed-what is the measured height distance from the CL of your lower unit bullet to sponson bottoms? (call me to discuss, if you'd like).
    Last edited by Jimboat; 08-02-2021 at 07:38 AM.

  7. #50
    Join Date
    Dec 2013
    Location
    Columbus Ohio
    Posts
    82
    Thanks (Given)
    8
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If that is the measurement you are asking for I didn't really measure it, but here is a picture. I used a yard stick to line up the lower unit with the bottom of the boat. If you look close it is about 3" past the tip of the nose cone and it reads 20" at the boat. So I believe the number you might want is 17"s.

    Thanks Ed

  8. #51
    Join Date
    Dec 2013
    Location
    Columbus Ohio
    Posts
    82
    Thanks (Given)
    8
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Baker343 View Post
    Did you get any pictures of the bottom of your hull and can you post.
    Can you measure the tunnels. Width and height. Entry, next to driver and rear.
    Be interesting to see how these numbers compare to say a 20 Stoker, 19 Laveycraft and a HST.
    Here are a couple of pictures I can get some measurements on Saturday.

    Thanks Ed

    Click image for larger version. 

Name:	IMG_2897 (640x480).jpg 
Views:	64 
Size:	193.2 KB 
ID:	480315Click image for larger version. 

Name:	IMG_2899.jpg 
Views:	77 
Size:	401.6 KB 
ID:	480316Click image for larger version. 

Name:	IMG_2899.jpg 
Views:	77 
Size:	401.6 KB 
ID:	480316Click image for larger version. 

Name:	IMG_2898 (480x640).jpg 
Views:	54 
Size:	165.1 KB 
ID:	480317

  9. #52
    Join Date
    Feb 2009
    Location
    Edgewater,B.C. CANADA
    Posts
    8,260
    Thanks (Given)
    179
    Thanks (Received)
    321
    Likes (Given)
    3578
    Likes (Received)
    1236
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Motor looks low, you can tell was designed for a jet. Has a rocker built into the sponsons, centre pod looks to be same height as outers. Outer sponsons look wide same width as centre. Take what ever advise Jim gives you.

    Dave
    1980 Cougar 19 tunnel,90 2.4L Bridgeport EFI in middle of restoration.
    1988 BAJA Sunsport 186, 96 225 Pro Max
    79 12' Auminum, 95 Merc 9.9
    RIP Stu
    "So many idiots, so few bullets"

  10. #53
    Join Date
    May 2013
    Location
    Huntiington Beach Ca
    Posts
    971
    Thanks (Given)
    137
    Thanks (Received)
    134
    Likes (Given)
    1401
    Likes (Received)
    638
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fasteddies69 View Post
    Here are a couple of pictures I can get some measurements on Saturday.

    Thanks Ed

    Click image for larger version. 

Name:	IMG_2897 (640x480).jpg 
Views:	64 
Size:	193.2 KB 
ID:	480315Click image for larger version. 

Name:	IMG_2899.jpg 
Views:	77 
Size:	401.6 KB 
ID:	480316Click image for larger version. 

Name:	IMG_2899.jpg 
Views:	77 
Size:	401.6 KB 
ID:	480316Click image for larger version. 

Name:	IMG_2898 (480x640).jpg 
Views:	54 
Size:	165.1 KB 
ID:	480317
    Do you have any pictures from the back looking forward

  11. #54
    Join Date
    Dec 2013
    Location
    Columbus Ohio
    Posts
    82
    Thanks (Given)
    8
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Not a good picture. I did put a level on the back 6' of the boat and it is flat. Also the boat weight is 1950 lbs. Took the interior out today only a 15 minute job and safety equipment out that weighed 220 lbs.Click image for larger version. 

Name:	IMG_2890 (480x640).jpg 
Views:	55 
Size:	208.5 KB 
ID:	480326

  12. Likes Baker343 liked this post
  13. #55
    Join Date
    Jul 2006
    Location
    Wisconsin
    Posts
    5,317
    Thanks (Given)
    998
    Thanks (Received)
    762
    Likes (Given)
    9049
    Likes (Received)
    5966
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Such cool looking boats. I looked at a couple around here.

  14. #56
    Join Date
    Jun 2004
    Location
    Pelican Lake, WI
    Posts
    1,261
    Thanks (Given)
    35
    Thanks (Received)
    17
    Likes (Given)
    95
    Likes (Received)
    153
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Maybe already said to much reading. If it was my boat wouldn't run anything bigger than than 26 chopper to carry bow
    That boat won't pack enough air to lift tail until mid 70mph. I say chopper for lake prop because them boats are know to give you wet ride. We have one on our lake that ran 92 with Bridgeport. I also think you have way to much set back. There is a pretty solid rule on how far drive shaft is supposed to be from pad give or take inch or two. Nice boat always one of my favorites right along with riot. Good luck be safe wear your safety gear.

  15. #57
    Join Date
    Aug 2015
    Location
    Southeast
    Posts
    1,058
    Thanks (Given)
    134
    Thanks (Received)
    79
    Likes (Given)
    48
    Likes (Received)
    614
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    3rd time... hold a long straight edge on bottom of center pod sticking out towards the lower unit so you can compare the height of the prop shaft in relation to the bottom of hull. Adjust engine height so prop shaft is 1 inch higher than the bottom of the boat. You may need to adjust set back and other stuff as well. But if your prop shaft is 4 or 5 inches below the bottom the hull, which it sort of looks that way in pics, its not gonna go fast. You have to run the bullet of the lower unit half out of water.
    Bullet CC w/ 225 Promax - Sold
    STV ProComp w/ 225 Promax
    STV Procomp with 280
    25 Liberator "The Battleship"
    Blazer 650 Pro Tour

  16. Likes Jimboat liked this post
  17. #58
    Join Date
    Dec 2013
    Location
    Columbus Ohio
    Posts
    82
    Thanks (Given)
    8
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by 97 TWISTER View Post
    Maybe already said to much reading. If it was my boat wouldn't run anything bigger than than 26 chopper to carry bow
    That boat won't pack enough air to lift tail until mid 70mph. I say chopper for lake prop because them boats are know to give you wet ride. We have one on our lake that ran 92 with Bridgeport. I also think you have way to much set back. There is a pretty solid rule on how far drive shaft is supposed to be from pad give or take inch or two. Nice boat always one of my favorites right along with riot. Good luck be safe wear your safety gear.
    We have tried a 25, 26 28,30 Chopper, several cleavers boat handles horrible. I had new set back plates new and moved the engine as close to the back as the boat as possible. Moved the static center of gravity to 4' With the original set back plates the center of gravity is at 3'6" . Did not notice any change in how the boat handled. Best prop for top speed and best handling so far has been a 4 blade 27, Bought a 28 4 blade lowered the rpm about 200 rpm to 6300 rpm.

    Thanks Ed

  18. #59
    Join Date
    Dec 2013
    Location
    Columbus Ohio
    Posts
    82
    Thanks (Given)
    8
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DangerNewb View Post
    3rd time... hold a long straight edge on bottom of center pod sticking out towards the lower unit so you can compare the height of the prop shaft in relation to the bottom of hull. Adjust engine height so prop shaft is 1 inch higher than the bottom of the boat. You may need to adjust set back and other stuff as well. But if your prop shaft is 4 or 5 inches below the bottom the hull, which it sort of looks that way in pics, its not gonna go fast. You have to run the bullet of the lower unit half out of water.
    Click image for larger version. 

Name:	IMG_2895 (480x640).jpg 
Views:	31 
Size:	205.0 KB 
ID:	480344Click image for larger version. 

Name:	IMG_2894 (480x640).jpg 
Views:	30 
Size:	198.6 KB 
ID:	480345Here is how I have had it set up every time. My jack plate gauge goes from 0 to 8. 8 is the first picture all the way up. 0 is the second picture all the way down. 4 is half way and the prop shaft is at the bottom of the boat. With the engine set back at 15" the lower unit nose cone is 17" off the back of the boat. Let me know if I'm close to what you are taliking about. Thanks Ed

  19. #60
    Join Date
    Dec 2013
    Location
    Columbus Ohio
    Posts
    82
    Thanks (Given)
    8
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    5
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Click image for larger version. 

Name:	IMG_2884 (480x640).jpg 
Views:	31 
Size:	243.9 KB 
ID:	480348Click image for larger version. 

Name:	IMG_2893 (480x640).jpg 
Views:	29 
Size:	234.3 KB 
ID:	480349Click image for larger version. 

Name:	IMG_2900 (640x480).jpg 
Views:	36 
Size:	184.4 KB 
ID:	480350Click image for larger version. 

Name:	IMG_2902 (640x480).jpg 
Views:	37 
Size:	163.3 KB 
ID:	480351


    Maybe these might help. Short set back plate I made. Original set back plate. 6' level on the bottom of the boat, bottom seem perfectly flat.



Page 4 of 7 FirstFirst 1 2 3 4 5 6 7 LastLast

Similar Threads

  1. 21 eliminator scorpion 86' drag prop
    By moosenelson225 in forum Props, Setup, and Rigging
    Replies: 5
    Last Post: 04-19-2015, 08:58 AM
  2. Eliminator Scorpion
    By Goose man in forum Hulls up to 20'
    Replies: 0
    Last Post: 04-28-2014, 01:03 AM
  3. Eliminator Sport Cruiser setup/prop question
    By Todd98SE in forum Props, Setup, and Rigging
    Replies: 4
    Last Post: 02-16-2014, 07:59 PM
  4. 300 HP Johnson Prop setup 21' Eliminator
    By CDignition in forum Technical Discussion
    Replies: 24
    Last Post: 06-15-2005, 04:42 PM
  5. 20' Eliminator scorpion
    By Bulletboy in forum General Boating Discussion
    Replies: 5
    Last Post: 10-07-2004, 12:14 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Chris Carson's Marine