Trimming a Simmons

Discussion in 'Boat Design' started by Sawdust, Aug 16, 2011.

  1. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Using half ovals or thinking about strakes will not solve your problem with this boat. She chine walks because she has modest transverse bearing area aft (and other issues). At speed you lift up, reducing this area further, to the point she flops around. Coupled to this is the substantial topside flare, which generates a lot of turbulence along the chines, which of course is unstable and the boat arbitrarily gets good and bad "bite" along the chines, as this disturbed flow crosses over them.

    You could employ runners, similar to a Bartender, effectively increasing transverse area.
     
  2. Sawdust
    Joined: Aug 2011
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    Location: New York, USA

    Sawdust CEO & sweeper

    Thanks, PAR, I'll chalk that up in the "throttle back" column. I looked at the Bartender

    http://www.bartenderboats.com/

    and was surprised at how similar the hull shape is to the Simmons; appears to be just a bit more beam for the length. Of course, "just a bit" in hydrodynamics is an inadequate descriptor. I was pleased to find on my last prop test that getting the trim tabs very carefully adjusted seemed to prevent my chine walking problem. Of course they're set as far outboard as possible, and as they get plenty of bite, I believe they have contributed to lateral stability as well as trim.
     

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  3. tabman
    Joined: Aug 2008
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    Location: Mount Pleasant, SC

    tabman Junior Member

    Stu,

    The Trim Tabs look really great, and the bottom mount hinges on them look perfect. If you don't mind I am going to forward the pictures and thread to a few folks at the factory so they can see them installed and read about the results.

    Tom McGow
    Bennett Marine
     
  4. Sawdust
    Joined: Aug 2011
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    Sawdust CEO & sweeper

    Forward away! I'm a happy customer!

    Stu
     
  5. tabman
    Joined: Aug 2008
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    Location: Mount Pleasant, SC

    tabman Junior Member

    Thanks Stu!

    Tom
     
  6. Sawdust
    Joined: Aug 2011
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    Location: New York, USA

    Sawdust CEO & sweeper

    Still waiting for the next prop (10D x 12P 3blade) to ship in. Have been working on a marketing campaign in the meantime: andersonboatworks.wordpress.com

    By itself, the website is a quiet as a graveyard, but coupled with Google Adwords, I'm getting a little traffic, though not enough to convince me I won't still own this boat in the spring (which may or may not be a bad thing!) Winter is still AWOL in Upstate NY, so I hope to get the next test done this week.

    Stu
     
  7. Sawdust
    Joined: Aug 2011
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    Location: New York, USA

    Sawdust CEO & sweeper

    Successful prop test

    Finally got the 10"D x 12"Pitch propeller. Lots of ice on the ramp, but the water was glassy and the wind was calm. At wide open throttle, the tach rose to exactly 6000 rpm. The boat gets up completely on plane and is fine going straight ahead at WOT, but maneuvering at that speed can be exciting :eek: --definitely recommend easing back on the throttle before making a major change in direction, or learning to play the trim tabs at the same time.

    Just for kicks, I put the 13"Pitch unit back on, as I didn't have the trim tabs on when I originally tried it. The boat came up to plane just fine, but the tach only climbed to 5400rpm and the engine sounded deeper and louder--obviously laboring at capacity. So I swapped back to the 12"Pitch prop and have settled, making my dealer very happy as the props were beginning to line up on his shelves.

    So, now I can winterize the whole thing, unless someone hits my website

    http://andersonboatworks.wordpress.com

    soon and wants it delivered on Christmas :D .
     
    1 person likes this.
  8. Sawdust
    Joined: Aug 2011
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    Location: New York, USA

    Sawdust CEO & sweeper

    Duhhh!

    It has just dawned :idea: on me that the reason I'm experiencing excessive roll :eek: when maneuvering at high speed relates directly to the adjustments I made to the motor mounting when trying to get the boat to trim without the trim tabs. Since the tabs were installed, I've never returned the motor to a more trim-neutral position; consequently, when I turn, the prop is pulling UP :!: to the outside of the turn, forcing the chine on the inside of the turn down :mad:. I need to get the motor shaft more vertical and rely more on the trim tabs to lift the aft end. I'll test out the theory this weekend if there's no ice on the lake.
     
  9. Sawdust
    Joined: Aug 2011
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    Location: New York, USA

    Sawdust CEO & sweeper

    Icebreaker

    As mentioned in my previous post, I did get out just before New Years. By sheer luck, I towed the rig in with my front wheel drive van, not my rear wheel drive pickup; the truck would never have gotten back up the ramp with all the ice built up at the strand line. Had to paddle out of the slip through a mosh of 40 pound ice floes to reach open water.

    Performance on turns was greatly improved by getting the motor more vertical. Unfortunately, the additional downward pressure on the tabs lifted the transom a bit higher, so at nearly WOT the prop sucked air. Came home happy at the improved turning performance but a little let down that this saga is not over yet. As soon as I got access to a sky hook, I put the motor mount into its lowest set of bolt holes, gaining an inch of prop depth (and, of course, adding an inch to the draft.)

    We've had two weeks of nights in the 5 below to 15 above zero (F) range, and the lake looks like a billiard table, so the next test is several weeks away.

    For those of you interested in marketing, I offer the following stats:

    YouTube video views to date: 680 (451 USA, 47 CANADA, 24 Turkey, 15 Britain, balance in 48 other countries) Within the USA, the most active states are 53 FL, 51 NC, 44 NY, 26 CA, 25 WA, 24 MA, balance in 40 other states.

    Website (WordPress) page views: 1521 to date; busiest day 2 Jan (70).

    Google Adwords (12/06/11 to present) 55049 impressions, 753 clicks, click-through rate 1.37%, costing $285 or 38 cents per click. Note that Adwords is only feeding in about half of the traffic to my website.

    Is it nearly Spring yet?

    Stu
     
    Last edited: Jan 22, 2012
  10. Sawdust
    Joined: Aug 2011
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    Location: New York, USA

    Sawdust CEO & sweeper

    Marketing update 2/22/12

    YouTube video views to date: 1124 (690 USA, 72 Canada, 44 Turkey, balance in 65 other nations) In the USA, 72 FL, 65 NC, 61 NY, 43 CA, 42 WA, 30 MA, and 41 other states.

    Website: 2162 page views to date

    Adwords: 97,714 impressions yielding 1276 clicks, click-thru rate 1.31%, costing $563 or 44 cents per click

    Something had boaters stirred up Feb 8 to 15 as website traffic was up sharply, but has since settled back to January levels.

    Stu
     
  11. BPL
    Joined: Dec 2011
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    BPL Senior Member

    Can you tell the asking price?
     
  12. Sawdust
    Joined: Aug 2011
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    Location: New York, USA

    Sawdust CEO & sweeper

    It's a fishing boat and I'm fishing for offers. If I can't get more than what I'd have to pay for a comparable Boston Whaler, I'll keep it. Every trip out is an advertising adventure.
    Stu
     

  13. BPL
    Joined: Dec 2011
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    Location: Home base USA

    BPL Senior Member

    Understandable. Rarer and prettier than a whaler :)
     
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