The rope trick.

Discussion in 'Downeast Boat General Discussion' started by HUNTHARD, Aug 6, 2018.

  1. Robb baker

    Robb baker Member

    Joined:
    Jun 4, 2017
    Posts:
    15
    Likes Received:
    6
    Thanks for your comment. Aboard Lucille my interest is completely focused on improved efficiency. We use her as a cruising platform and burn rate is important. I read good things about the interceptor approach to trim but I rarely read anything but side comments regarding efficency. Trim angle and cruise speed are acceptable as is so it is a very costly approach for a potential improvement.

    Lucille is hard chine with the long keel section cut away to a short stub. Plus water tank is central and fuel saddle tanks are self equalizing as they both feed a central day tank. The need for independent trim control is very low prority.

    The cost of hull prep and such devices would be tough to justify when only looking for efficency which seems no data is available to quantify.

    This fall I plan to use prop speed on prop and rudder and see what results I get. Also seems that if a 1/2 in rope can disrupt flow enough to gain stern lift a few sections of 1/2 round applied to the stern would have somewhat similar results. Any expierence on this forum regarding such an approach ?

    I have read that increasing the beam at the chine is the most effective way to improve lift aft but complicates haul out.

    Thanks for the feed back
    Rob
     
  2. Robb baker

    Robb baker Member

    Joined:
    Jun 4, 2017
    Posts:
    15
    Likes Received:
    6
    I agree with that, certainly response time would likely be quicker. Tx.
     
  3. seasar33

    seasar33 Member

    Joined:
    Apr 25, 2012
    Posts:
    32
    Likes Received:
    26
    Ronnie made those Lenco/ blades on his 38, fabricated aluminum plate with a channel on both sides for the plate to slide up and down. Worked well so I can understand why he did it on the 43. I think I noticed that he was able to recess into the transom on the new boat. Simple design and affordable. Wired into the ignition so when he shut off boat they automatically went up. Performance wise he could seriously stuff the bow, not that he wanted to but he showed me how well they worked. Cheaper version of the Humphreys and if an actuator broke it was easily repairable.
     
    Silverfish and restless like this.
  4. PatriciaLynn

    PatriciaLynn Member

    Joined:
    Jul 18, 2017
    Posts:
    67
    Likes Received:
    30
    Location:
    Cape E
    Boat Make:
    Repco
    Half round would work, but a simple wedge made out of fairing compound would be more efficient and marginally more work.

    You could rip down some marine ply into wedges on a table saw and use these as a core as well. Maybe more work, maybe less. Either way, more efficient than a piece of half round.

    Remember, no one ever said using a trim rope is the best solution, it is just an easy, field expedient way to bring down the bow without making permanent changes to the hull.
     
    sailor of fortune likes this.
  5. Rambler

    Rambler Member

    Joined:
    Jul 31, 2012
    Posts:
    83
    Likes Received:
    64
    Location:
    Rhode island
    Boat Make:
    Wesmac
    Huntard, did you ever decide what route you wanted to go. I put a 1/2" rope under my 42' Wesmac. It puled out the back except for each corner. It made a huge difference so it doesn't look like you need much. I was thinking of glassing on a small wedge this winter.
     
  6. Robb baker

    Robb baker Member

    Joined:
    Jun 4, 2017
    Posts:
    15
    Likes Received:
    6
    I'm interested in your findings. Also thinking of some form of generating lift aft. If the rope trick delivers results I would think glassing a preformed half round to the underside of the hull. Kind of a perminant rope trick. I have a wesmac 38 and is in need of some lift aft without increasing drag greatly.

    What results did you see from the rope trick ?
     
  7. Rambler

    Rambler Member

    Joined:
    Jul 31, 2012
    Posts:
    83
    Likes Received:
    64
    Location:
    Rhode island
    Boat Make:
    Wesmac
    When the rope was completely under the boat, it brought the bow down way too much. After the majority of it slipped off it dropped the bow over a foot and didn't seem to make the boat wallow in a following sea. Performance was not changed noticeable but visibility was much improved. My thought is that a half round will act like the rope but may offer some drag. My thought is a small wedge no more that a half inch at the high end will be more efficient. The question is how long to make it and where to place it.
     
  8. Blitzen

    Blitzen Captain

    Joined:
    Sep 1, 2011
    Posts:
    3,178
    Likes Received:
    1,605
    Occupation:
    Ex Merchant Marine
    Location:
    Sumday Isle, RI
    Boat Make:
    1991 Boston Whaler Outrage 19
    Rambler, if you want to just try out the wedge, you could just glue a shingle on the bottom and see how it works out, and then adjust accordingly to get it where you want and then make it more permanent when the boat comes back out.
     
    Keelboater likes this.
  9. eyecatcher

    eyecatcher Senior Member

    Joined:
    Sep 30, 2012
    Posts:
    102
    Likes Received:
    24
    You would have to figure what size rope you want to use 100% of the time in any and all sea conditions, loads etc. Then you can calculate the area of the rope across the wetted width of the transom, then convert that to equivilant area of what ever material want to permanenantly affix ie 1/2 round, wedge etc divided into two separate pieces.. I used hollow back half oval stock, you can find it in 3/4", 1", 1.25, 1.5"wide outside of the prop wash/rudder path but only on the flat part of the hull(not on the round bilge) right under the transom or no more than 1/2-1 inch foward of the stern. It will require some trial and error, if you glass it you can go right to the transom and grind it down etc. had a friend with a downeaster that listed, he ran a single large single wooden wedge glued/glassed to the hull to even out the running attitude. You would basically locate them where you would do trim tabs on a traditional boat
     
    Last edited: Oct 11, 2018
  10. El Mar

    El Mar Captain

    Joined:
    Sep 1, 2011
    Posts:
    6,422
    Likes Received:
    2,218
    Location:
    Westbrook, CT (The Asshole State)
    Boat Make:
    43 Tiara Open DDEC, Grady white 268 Islander 250 OX66, 15 Boston Whaler Sport ETec 60
    Why not just QL tabs, zipwakes, etc.

    Gotta be cheaper than messing with haul outs and wedges plus they are adjustable.

    Might be days you want the bow up.
     
    PBianculli likes this.
  11. Blitzen

    Blitzen Captain

    Joined:
    Sep 1, 2011
    Posts:
    3,178
    Likes Received:
    1,605
    Occupation:
    Ex Merchant Marine
    Location:
    Sumday Isle, RI
    Boat Make:
    1991 Boston Whaler Outrage 19
    Really! Coming from the guy that builds everything himself.
     
    El Mar likes this.
  12. offshore27ns

    offshore27ns Senior Member

    Joined:
    Dec 17, 2011
    Posts:
    384
    Likes Received:
    284
    Location:
    Chester, Nova Scotia
    Boat Make:
    Wesmac
    I have zip wake

    Best choice as you can adjust to different percentages of deployment for different speeds
     
    PBianculli likes this.
  13. Fishonnelsons

    Fishonnelsons Captain

    Joined:
    Sep 14, 2015
    Posts:
    569
    Likes Received:
    308
    Occupation:
    Charter boat Captain
    Location:
    Truro, Cape Cod
    Home Page:
    Boat Make:
    38 Wesmac
    I was thinking zipwakes, then read this, talked to a few people, never even tried the rope yet, but was leaning toward the wedge. Keep it simple, have to be less cost, etc.

    But, have decided to go with zipwakes. Varying sea conditions, passenger load side to side with charters, ability to be flexible versus one way only, all the time with the wedge. Figure this might be the boat for the duration, so why not go all in.
     
  14. Diesel Jerry

    Diesel Jerry Captain

    Joined:
    Oct 25, 2015
    Posts:
    3,367
    Likes Received:
    1,617
    Occupation:
    Marine Diesel Mechanic and Systems Technician
    Location:
    South Freeport, ME
    I wouldn’t waste the time and material on a wedge. Best to do something that is variable. Boats change with fuel, water, gear, and people. Not to mention weather conditions.
     
    El Mar and PBianculli like this.
  15. Fishonnelsons

    Fishonnelsons Captain

    Joined:
    Sep 14, 2015
    Posts:
    569
    Likes Received:
    308
    Occupation:
    Charter boat Captain
    Location:
    Truro, Cape Cod
    Home Page:
    Boat Make:
    38 Wesmac
    Really good points Jerry
     
  16. tunaorlater

    tunaorlater Captain

    Joined:
    Sep 9, 2011
    Posts:
    3,970
    Likes Received:
    2,026
    Occupation:
    LIPA lineman
    Boat Make:
    40' Northern bay
    I don't think a wedge is the answer. I think you need the restriction of the rope or the square edge of the tab to push the bow down. A backwards wedge may work better. Or am I just over thinking this?
     
    PBianculli likes this.
  17. Genius

    Genius Captain

    Joined:
    Feb 11, 2016
    Posts:
    1,769
    Likes Received:
    681
    Location:
    Rhode Island
    Wedges work, I've got one a Jarvis Newman. Boat also has trim tabs also.
     
  18. El Mar

    El Mar Captain

    Joined:
    Sep 1, 2011
    Posts:
    6,422
    Likes Received:
    2,218
    Location:
    Westbrook, CT (The Asshole State)
    Boat Make:
    43 Tiara Open DDEC, Grady white 268 Islander 250 OX66, 15 Boston Whaler Sport ETec 60
    Agreed.

    I know where not to waste my time. :D
     
  19. tunaorlater

    tunaorlater Captain

    Joined:
    Sep 9, 2011
    Posts:
    3,970
    Likes Received:
    2,026
    Occupation:
    LIPA lineman
    Boat Make:
    40' Northern bay
    Did you add the wedge after trying the rope?
     
  20. Genius

    Genius Captain

    Joined:
    Feb 11, 2016
    Posts:
    1,769
    Likes Received:
    681
    Location:
    Rhode Island
    No, it was done before me. So, I guess it would be fair to say that I really don't know if they work...because I have nothing to compare it to. From the best I can surmise it appears it was done to get the ride to a middle ground....or, a base line. The wedge is small. Tabs look like they were added somewhere along the way. Using the tabs allows one to stuff the bow down if needed. I don't really use them and I wouldn't suggest tabs to anyone with a 10-12knot boat, the speed isn't there to utilize them.
     

Share This Page