Page 1 of 3 123 LastLast
Results 1 to 20 of 55

Thread: Hull Extensions

  1. #1
    Join Date
    Jul 2009
    Location
    'Estrella del Sur' is currently on the hard in Fort Pierce, Florida for hurricane season.
    Posts
    678

    Default Hull Extensions

    I am considering adding hull extensions to my 1994 Solaris Sunstream 40 in order to compensate for all the of the additional weight that is now being carried aft. I am very interested in hearing from those who have done something similar themselves, but my current thinking on the easiest way to accomplish this is as follows:

    Take a plug off the lower portion of the existing transoms and topsides to the desired length/height for the extensions, cut out a section from the middle so that the forward end of the plug will line up with the exisitng transoms, fiberglass it back together and use it as a female mould.

    Assuming this will work in making the mould for the hull form, I would also appreciate some advice on the lamination schedule and on gelcoating over epoxy resin. I would prefer to use epoxy for both constructing the hull extensions and attaching them to the existing transoms; having said that, I would also like to avoid having to paint the entire boat and would prefer attempting to match the existing gelcoat.

    Any comments or suggestions?

    Brad

  2. #2
    Join Date
    Dec 2008
    Location
    Great South Bay, Long Island, NY USA
    Posts
    798

    Default Re: Hull Extensions

    Brad,

    While not a marine engineer, my opinion that if not done correctly there will be a lot of turbulence (I'm not sure that is the correct term) off the aft portion of the hulls, which will tend to slow you down.

    Of course, the increased buoyancy may offset this.

    I would post a direct question to Richard Woods, who is certainly more qualified to answer.

    Marshall
    "People sail for fun and no one has yet convinced me that it's more fun to go slow than it is to go fast." -- Dick Newick

  3. #3
    Join Date
    Jul 2009
    Location
    'Estrella del Sur' is currently on the hard in Fort Pierce, Florida for hurricane season.
    Posts
    678

    Default Re: Hull Extensions

    Actually Marshall, I am pretty confident that by raising the transoms back above the water I will reduce turbulence (and I will be following the flow of the hulls aft as my plug will be taken from them).

    Brad

  4. #4

    Default Re: Hull Extensions

    1309.JPG

    1334.JPG

    1345.JPG

    1432.JPGBrad,

    Here are some pics of our stern extensions. They were done in epoxy and painted to match the gelcoat. I hope the pics explain the basic process.

  5. #5
    Join Date
    Aug 2010
    Location
    Far North Queensland Australia
    Posts
    289

    Default Re: Hull Extensions

    Brad Good to Excellent :y) Very well done. Great pics. Very explanatory - 50 out of 10 , mate :t) for posting. For sure that will make a difference of note when sailing.

    Next - try redisigning those rudders - they are - way off the mark

    Do come back in here & let us all know just how much you enjoy the new extensions. Congratulations. Ciao, james

  6. #6
    Join Date
    Jul 2009
    Location
    'Estrella del Sur' is currently on the hard in Fort Pierce, Florida for hurricane season.
    Posts
    678

    Default Re: Hull Extensions

    Thanks so much for this, smj. A few (actually four) questions:

    1. How did you attach the strapping for the mold to the hull - hot glue or mechanical fasteners?
    2. What type of foam was used and is this applied by spray?
    3. I am only proposing a 2 foot extension - basically up to the point that you flattened out the underbody curve. Is there any particular reason you made yours as long as you did?
    4. What lamination schedule did you use?

    Thanks so much again for the pictures, as they are worth a thousand words - and yes, sorry I am asking for a few more!

    Brad
    Last edited by Southern Star; 7th December 2011 at 01:01 PM. Reason: sp

  7. #7
    Join Date
    Oct 2008
    Location
    Brighton, UK
    Posts
    2,843

    Default Re: Hull Extensions

    I expect they will be great in 90% of conditions

    I am just a tad concerned at what woud happen in a stern breaking sea situation, or have you ruled out use of series drogues.
    Insanity is continuing to do the same thing and expecting different results

  8. #8
    Join Date
    Oct 2008
    Location
    kefalonia
    Posts
    235

    Default Re: Hull Extensions

    Hi Brad , I extended my transoms by over 2 ft and this is how it was done :
    1. jigsaw off the transom steps from the aft face of the sterns , no cutting of the hull itself . very simple , cut right out to the hull /step corners to allow max width for refitting later.
    2 take white hardboard sheets , 8x4 were enough for me , and screw them directly onto the existing hull with self tappers , this will allow the existing form and taper of the hull to continue symmetrically , aft .
    3 lay up with cloth of choice inside this "mould " adding 2/3 1/2 pipe pvc stringers overlapping the original hull inside , leaving all edges proud .
    4 once cured cut the profile wanted to suit the original steps which were cut out , then lay the steps across the new stern and scribe around the hull/ step , cut to scribe then laminate the steps back on , reinforcing the corners with extra cloth and lay up the 1/2 pipes inside onto the new section .
    5 fill , fair and paint ,
    it worked really well on Wild Honey and has stayed put for 7 years without any problems .

    (when you want to extend the bows , just ask, we did that too !)
    I didn,t get where I am today by being somewhere else !

  9. #9

    Default Re: Hull Extensions

    Quote Originally Posted by Talbot View Post
    I expect they will be great in 90% of conditions

    I am just a tad concerned at what woud happen in a stern breaking sea situation, or have you ruled out use of series drogues.
    By extending the stern of the boat they are increasing it's bouyancy. In stern breaking sea conditions, a more bouyant stern would be a considerable asset.

  10. #10
    Join Date
    Jul 2009
    Location
    'Estrella del Sur' is currently on the hard in Fort Pierce, Florida for hurricane season.
    Posts
    678

    Default Re: Hull Extensions

    Wow Gramos, that must have been quite the project! Right now I am actually riding well above the waterline on the bows, and as all additional weight has gone aft I don't see lengthening the bows as being necessary. Great idea regarding the steps. I was only planning on extending the hulls from the level of the bottom step down - i.e., to lengthen the underbody up to a swim platform. It wasn't clear to me, but were you using the pipes as stringers in lieu of, or in addition to core material?


    Brad

  11. #11
    Join Date
    Jul 2009
    Location
    'Estrella del Sur' is currently on the hard in Fort Pierce, Florida for hurricane season.
    Posts
    678

    Default Re: Hull Extensions

    I agree with 44C - the additional bouyancy can't do anything but help and if constructed to appropriate scantlings, should be no weaker than any other part of the hull. In fact, they will probably be a bit stronger as they will be attached to, and only two feet past a solid bulkhead - the existing transoms. Regardless, even if the attachment failed (and it shouldn't), they are in essence sacrificial as the existing transoms will remain intact.

    Brad

  12. #12
    Join Date
    Jul 2009
    Location
    Big Pine Key Fl
    Posts
    34

    Default Re: Hull Extensions

    SMJ,

    Did you notice or feel anything different after the extensions were put on?

  13. #13
    Join Date
    Oct 2008
    Location
    kefalonia
    Posts
    235

    Default Re: Hull Extensions

    Quote Originally Posted by Southern Star View Post
    Wow Gramos, that must have been quite the project! Right now I am actually riding well above the waterline on the bows, and as all additional weight has gone aft I don't see lengthening the bows as being necessary. Great idea regarding the steps. I was only planning on extending the hulls from the level of the bottom step down - i.e., to lengthen the underbody up to a swim platform. It wasn't clear to me, but were you using the pipes as stringers in lieu of, or in addition to core material?


    Brad
    The stringers were laid to give rigidity and strength , the extensions were solid laminations of cloth/ grp , no actual core material . Same as the original hull below the waterline . We did look into low swim platforms but it actually suited the Sunstar to have a higher platform which is very useful for stepping onto the dock when alongside .
    I didn,t get where I am today by being somewhere else !

  14. #14
    Join Date
    Dec 2008
    Location
    Now cruising in the SUN! In Malta.
    Posts
    1,063

    Default Re: Hull Extensions

    Quote Originally Posted by gramos View Post
    (when you want to extend the bows , just ask, we did that too !)
    Hi Gramos,

    I'd be interested in your bow extension job - do you have some more excellent pictures of the work done?

    Thanks
    Roger

    ------------------
    I look to the future, because that's where I am going to spend the rest of my life - George Burns

  15. #15

    Default Re: Hull Extensions

    Quote Originally Posted by Southern Star View Post
    Thanks so much for this, smj. A few (actually four) questions:

    1. How did you attach the strapping for the mold to the hull - hot glue or mechanical fasteners?
    2. What type of foam was used and is this applied by spray?
    3. I am only proposing a 2 foot extension - basically up to the point that you flattened out the underbody curve. Is there any particular reason you made yours as long as you did?
    4. What lamination schedule did you use?

    Thanks so much again for the pictures, as they are worth a thousand words - and yes, sorry I am asking for a few more!

    Brad
    Brad,
    We used drywall screws to attach the battens to the hull.
    The type foam used was Kledgecell. Screwed through the battens into the foam to hold the shape until the inside was stringered and glassed.
    I went with a 4' extension because it brought the sterns clear of the water. Also everyone else went with 3' extensions so.......
    I can't remember the lamination schedule.
    The work was done by a friend of mine. I helped a little but not enough to take any credit.

  16. #16
    Join Date
    Oct 2008
    Location
    kefalonia
    Posts
    235

    Default Re: Hull Extensions

    Brad , I posted some pics , look in "photos ", scary stuff !
    cheers , gramos
    Last edited by gramos; 8th December 2011 at 11:42 AM. Reason: additional text
    I didn,t get where I am today by being somewhere else !

  17. #17

    Default Re: Hull Extensions

    Quote Originally Posted by DWT View Post
    SMJ,

    Did you notice or feel anything different after the extensions were put on?
    Yes, the boat definitely has a smoother ride. A lot less tendency to pitch or hobbyhorse. Also gained speed and the ability to surf waves better, which could be good and bad.

  18. #18
    Join Date
    Jul 2009
    Location
    'Estrella del Sur' is currently on the hard in Fort Pierce, Florida for hurricane season.
    Posts
    678

    Default Re: Hull Extensions

    Thanks so much smj and gramos for all of the help. I guess the questions for me now are whether I should go longer than 2 feet and whether I should move the entire transoms out, or just a swim platform.

    I intend for obvious reasons (better adhesion, less water permeable) to use epoxy resin, but have heard that it is difficult at best to get gelcoat to adhere to it. I would vastly prefer using gelcoat and blending it to match the exisitng gelcoat; I just can't imagine blending 2 part paints with gelcoat and being able to eliminate overspray. Does anyone have any advice?

    Brad

  19. #19
    Join Date
    Oct 2008
    Location
    Cornwall UK
    Posts
    255

    Default Re: Hull Extensions

    If you are working into a female mould, you'll gelcoat the mould first and the epoxy lay-up will bond to the gel extremely well. If you are using a male mould, where you have to finish the exterior last, the gel will bond very poorly to the epoxy laminate and a two-pack paint system is the way to go.

  20. #20

    Default Re: Hull Extensions

    With a 17 year old boat, colour matching is going to be a challenge.

Page 1 of 3 123 LastLast

Posting Permissions

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