Bottom Blueprinting
+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast
Results 1 to 14 of 43

Thread:
Bottom Blueprinting

  1. #1
    Senior Member Factory502's Avatar
    Join Date
    Feb 2008
    Posts
    100

    Default Bottom Blueprinting

    I know that every boat is different as far as what is required to tune a bottom but does anyone have a rough idea of what it would cost to do a southwind v bottom- and at what point is the hook too bad to even mess with????

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    I'm No Expert Shaun's Avatar
    Join Date
    Feb 2008
    Location
    San Clemente, Ca
    Posts
    3,139

    Default

    My boat/bottom is a splash if a southwind... i'll be posting alot of info here soon as i learn/get it.

  4. #3
    Senior Member Brendellajet's Avatar
    Join Date
    Dec 2007
    Location
    Ladera Ranch
    Posts
    2,135

    Default

    Shaun, who is doing your boat?

    IMO, after the last southwind/southwind copy that was done, even with the best intentions turned out less than desirable. This is not childs play. IMO there are probably 4 or 5 people in SOCAL who know what to do to that hull, to make it right. Jeff Bennett is the only one I am aware of that is in the business of doing this-you may have to beg though as I heard he is cutting back and catering to racers only. May be just a rumor.
    "He is a lover, not a fighter. But he's also a fighter, so dont get any ideas."

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Senior Member H20MOFO's Avatar
    Join Date
    Dec 2007
    Posts
    4,288

    Default

    Quote Originally Posted by Factory502 View Post
    I know that every boat is different as far as what is required to tune a bottom but does anyone have a rough idea of what it would cost to do a southwind v bottom- and at what point is the hook too bad to even mess with????
    I don't know chit...but I'm curious how much hook do you have??
    Another Hot Boat refugee

  7. #5
    Cas
    Cas is offline
    Angry American Cas's Avatar
    Join Date
    Jan 2008
    Location
    NorCal
    Posts
    3,103

    Default

    this is a step by step by arguably the best in hull blueprinting so you can do it yourself


    Hull Blueprinting 101 by Jeff Bennett-
    Hull blueprinting means different things for different hull designs. I will limit this discussion to vee bottom jet boat hull blueprinting. It is assumed that the reader has a working knowledge of body work and fiberglass repair. It is best to talk with or get assistance from someone who understands this skill. Also, there are many ways to blueprint a hull, this is the way I go about it.


    Basically, vee bottom hull blueprinting means to return the bottom of the hull to the shape that the manufacture originally intended. Over time, hulls can change shape or warp due to improper trailer fit, or hulls being removed from the mold too early. This warping often results in a 'hook", which is when the bottom of the boat at the transom is lower than the adjacent hull forward. This hook resembles a trim tab or cavitation plate in the down position. The result of this hook is to generate more lift at the rear of the boat, which forces the nose of the boat downward. The faster the hull speed, the more this occurs. Because of this tendency to push the nose down, the boat is prevented from getting loose (free from the water) and top speed is reduced. Usually the prime motivation of hull blueprinting is to increase top end speed. There are many steps to hull blueprinting.


    First, the amount of hook must be measured to determine whether or not the effort is worthwhile. The easiest way to do this is to use a 5-foot straight edge and place it lengthwise from the transom forward. Examine the bottom at several locations; down the centerline, at each lifting strake and at least one location between each lifting strake. You should concentrate on the lower part of the hull, usually at least 2 or 3 lifting strakes outboard from the centerline. At every location measure the gap(s) between the straight edge and the hull. The gap(s) is the amount of hook. If the hook is any more than 1/16" then a hull blueprint may be worthwhile. If you decide to go ahead and blueprint the hull, there are a series of steps required to accomplish the task.
    1) The boat needs to be stripped (remove the motor, battery, fuel, steering wheel, possibly the upholstery and anything that will fall out or be in the way when the boat is turned upside down.
    2) Now it is time to turn the boat upside down. Used car tires with blankets over them work well for this. First lay out 6 to 8 tires on the ground behind the boat and with the help of 6 or 8 of your friends (more if the boat is over 20 feet) and slide the boat off the trailer and on to the tires. Next, line up 3 or 4 tires in a location that when the boat is lifted up on one side, they will be between the ground and the hull on the opposite side. Have every one except 1 person gradually lift up on one side of the boat and the other person make sure that the boat does not slide off the tires. When the boat is at 90 degrees and resting on its side have each person one by one go around to the opposite side and then gradually let the boat down. One person needs to move the now vacant tires to the other side to be a resting-place for the boat when it is upside down. As you are letting the boat down, make sure nothing drags on the ground and that the tires are completely supporting the boat. Should you have a hoist, there are many ways to aid in this process, but I am not going to go into those here.

    3) Using the straight edge, make a detailed contour map of the bottom by measuring and marking how deep the gap is at various locations. A grease pencil is a good choice for this map. The blueprint area should be 5' long and out to the 3rd strake outboard from the centerline (2nd if you have a 2 strake per side boat).
    4) The amount of the step will determine how the 'hook' should be filled in. Never, by the way grind out a hook; many manufactures have made this mistake and ruined otherwise good hulls. Anything less than a 1/16" gap should be filled with body filler. Any body filler will work as long as primer and or paint seal it. The best filler is 3m Premium grade filler, which is waterproof. Between 1/16" and 1/8" gap can be filled with either Duraglass or fiberglass mat and resin. Anything over 1/8" should be filled with fiberglass mat and resin.
    5) Next, you need to grind the areas that will be filled. Use a 40-grit disk on a body grinder. The gel coat does not have to be completely removed, but all the shinny spots need to be eliminated and the surface must be rough.
    6) If you need to fill any areas with fiberglass, use 3 oz. mat and resin and do them first. A single lay up of 3 oz. mat is roughly 1/16' thick when soaked with resin. If you are not going to add fiberglass, go on to Step 7. Use a roller and remove any air bubbles. Try not to work in the sun. You can use fiberglass cloth over the mat, but you really do not need to add any strength and in this case mat alone will work fine.
    7) Once the fiberglass is dried, grind it with the body grinder and prep the surface for the body filler by washing that portion of the hull with acetone on a rag.
    8) Fill next with the Duraglass filler. Mix up a small batch of Duraglass and spread it on the areas you wish to fill. Using a straightedge and standing on the side of the boat, quickly place the straightedge lengthwise (relative to the hull) and slowly pull the straightedge towards you as you scrape the excess material off the bottom. Start the filling from the centerline and work outboard. When the Duraglass dries, use the body grinder again and smooth out the high spots. Repeat this process over the blueprinting area. Apply another application(s) until the hull is within 1/16" of being true.
    9) Now do the final filling using the regular body filler. This procedure is basically the same as Step 8, but instead of using the body grinder, use a long board with 40-grit sandpaper, sanding lengthwise. It will take three or four applications before the hull is straight.
    9b) The hull to intake interface needs to be blended. Just make sure that there is no part of the intake hanging below the boat, no forward facing steps and that you fill and smooth any gaps between the intake and hull. The finished blend should be a gradual entry and the intake should look as though it is part of the hull.
    10) Once the boat is straight, again use the long board with a 100-grit sandpaper and detail out the bottom. Some areas, especially around the intake will require hand sanding without the long board.
    11) Use glazing putty to fill the pinholes. Again sand with the 100-grit sandpaper.
    12) Mask the blueprinted area off and prepare the surface for primer by cleaning the surface with a thinner or acetone. If you use acetone, be careful to not remove the glazing putty, which will be attacked by the acetone.
    13) Primer the blueprinted area using a polyester primer. Put on a thick coat because it will help fill any remaining pinholes and seal the body filler. Dust coat the primer with a black lacquer to be used for the wet sanding step.
    14) Wet sand the primer with 220-grit wet/dry sandpaper. Follow that with 400-grit wet/dry.
    15) Now you are ready for the finish coat. Since polyester primer has been used, you have a few options on type of paint or Gel coat. I usually use catalyzed acrylic enamel or a lacquer based graphite finish (AKA speed coat), which is available from Rex Marine or Eddie Marine. Gel coat is the strongest finish, but it requires the most work. As I mentioned at the beginning, it is assumed that you have a working knowledge of bodywork. If you do not feel comfortable with the final paint step, either find someone who can do it for you or use the graphite paint because it is almost impossible to screw up.
    16) Let the final finish dry thoroughly (24 hours) and be careful not to scratch it when you put the boat back on the trailer. Now you are ready for the lake.

    Good luck!

  8. #6
    Senior Member Factory502's Avatar
    Join Date
    Feb 2008
    Posts
    100

    Default

    it is actually on a hondo, but the bottom is similar to a southwind, so I have been told- from the keel out to the first strake is about .090- the second strake is what concerns me- it is about 5/16"

  9. #7
    Senior Member
    Join Date
    Dec 2007
    Location
    corona calif
    Posts
    1,119

    Default Bottom Blueprinting

    Most of the boats that were built in the 70's were built to get the most out of the hull with the least amount of power. The Southwind is one of those boats the strake design is more aligined with this design.Straighten the bottom is one thing changing strake design is a whole different project.With todays power it has been my experience that the boat has way to much hydro dynamic lift and with todays power this is a bad combination.Boats today can generate more speed in 700 feet than the boat can handle.usually the boat will drive itself right out of the water and will not be able to maintain a good set.Make sure when you decide to blueprint the bottom you keep this in mind.

  10. #8
    Senior Member Factory502's Avatar
    Join Date
    Feb 2008
    Posts
    100

    Default

    I think I understand what you are saying, I think the trailer is the main culprate of the bottom issue, as many are- so the strake is equally warped with the bottom- if I fix the bottom only by filling in the hook, I would be cutting down the strake hieght, so to keep strake hieght the same, I would have to add to the strake to keep the dimension the same- Right???? or am I looking at this way wrong- Thanks in advance

  11. #9
    FAT GUY IN A TPR STEALTH NO REGRET$'s Avatar
    Join Date
    Jan 2008
    Location
    MENIFEE . CA
    Posts
    1,828

    Default

    Quote Originally Posted by Factory502 View Post
    it is actually on a hondo, but the bottom is similar to a southwind, so I have been told- from the keel out to the first strake is about .090- the second strake is what concerns me- it is about 5/16"
    Jeff Bennett's work is one of those rare things ,, often imitated ,,, but never duplicated ..want the best results .GET THE BEST .. and remember ,especially at higher HORSE POWER levels ...whom ever does your hardware and bottom work ....your putting your life /safety and investment in there hands.

    jmo
    "Life's tough......It's even tougher if you're stupid."

    -John Wayne

    ..JUST HAVING FUN..
    . . . .SIPPY CUP RACING. . . .
    MySpace URL:
    http://www.myspace.com/dp734taj

  12. #10
    Senior Member
    Join Date
    Dec 2007
    Location
    corona calif
    Posts
    1,119

    Default Hook

    No Mfg intentionally puts hook in the bottom of there boats .Most of the hook that we find on the bottom of boats was caused from post cure, improper bunking on the trailer, or the intake was over tightened upon instllation. Once the bottom is straightened then and only then will you find what kind of bottom you have to deal with. If you look at the bottom of your boat you'll find that the inside strakes stop about four feet from the transom.If you decide to use this style of bottom at top speed there is no area for the boat to ride on and the boat will develope handling probblems side to side or just drive itself right out of the water. Strake mods are necessary based on the kind of power you intend to run.Stock power the boat will probably be OK as the power goes up the boat will reach it's limit and handling problems will start.

  13. #11
    Senior Member Brendellajet's Avatar
    Join Date
    Dec 2007
    Location
    Ladera Ranch
    Posts
    2,135

    Default

    Quote Originally Posted by Factory502 View Post
    it is actually on a hondo, but the bottom is similar to a southwind, so I have been told- from the keel out to the first strake is about .090- the second strake is what concerns me- it is about 5/16"
    What hondo hull is this? Have a pic of the transom?
    "He is a lover, not a fighter. But he's also a fighter, so dont get any ideas."

  14. #12
    Senior Member gregb's Avatar
    Join Date
    Jan 2008
    Location
    Redondo
    Posts
    375

    Default

    Greg, what kind of strake mods would be in order, do you extend the inner ones back to the transon or is it much more involved?

  15. #13
    Senior Member
    Join Date
    Dec 2007
    Location
    corona calif
    Posts
    1,119

    Default Bottom

    Can you post pictures of the bottom.Extending the strakes to the transom is a possibility, but size will be the determining factor as well as what kind of power.

  16. #14
    Senior Member Factory502's Avatar
    Join Date
    Feb 2008
    Posts
    100

    Default

    Here is a pic of the bottom of the boat- the pump is going to be set back as well-
    Greg- what is the best way to go to put togather a respectable river boat? I am not really looking at getting into the triple digits, but more along the lines of putting togather a 500 to 550hp motor that will push the boat in the mid 80's +/-. Is it better to abandon the Hondo and go a completely different direction?- I understand the v bottoms have there limits and can get spooky when that limit is pushed- but I am not really in the position to buy a Daytonna, TPR, Place, etc.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	boat rebuild 001.jpg 
Views:	217 
Size:	85.7 KB 
ID:	38256   Click image for larger version. 

Name:	misc 070.jpg 
Views:	268 
Size:	89.8 KB 
ID:	38257  

+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in


Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95