Registered users don't see ads

High Trust

Discussion in 'Smaller Boats' started by GBGraham, Dec 17, 2017. Add this thread to a FAQ

  1. GBGraham

    GBGraham

    Joined Nov 10, 2017
    57 posts, 1 likes
    Hunter Legend 260
    Omega Gr Greece Epidavros
    I have read quite a lot on the pro's and con's of fitting a High Thrust prop to a standard engine. There seems to be a lot of different opinions so I have not really ended up with a conclusive answer. Have any of you guys got any first hand experience you could pass on please?
    From previous posts you may gather that I have only just purchased the H260 and I have not used the boat yet so I have no experience of it's performance.
    My engine is 2006 Yamaha 9.9 hp Long Shaft 2 stroke with what I believe to have the standard prop fitted (9 1/4 x 9 J). From what I can find here in the UK is a High Thrust (or Dual Thrust)
    9 3/4 x 8 or 9 1/4 x 11. These are all three bladed props.
     


  2. Cowpokee

    Cowpokee

    Joined Jan 8, 2015
    153 posts, 38 likes
    MacGregor 26S, Goman Express 30
    US Kerr Reservoir
    [QUOTE="My engine is 2006 Yamaha 9.9 hp Long Shaft 2 stroke .[/QUOTE]

    I have 9.9 Yamaha long shaft 4 stroke with the high thrust prop on a 26 foot boat. What I can report is that half throttle is all I ever use getting out of and into the marina. Great little engine.
     


  3. GBGraham

    GBGraham

    Joined Nov 10, 2017
    57 posts, 1 likes
    Hunter Legend 260
    Omega Gr Greece Epidavros
    Thank you for coming back to me, did you purchase as a HT or convert with a prop change? If I understand correctly the factory HT engine has a different gearbox.
     


  4. Cowpokee

    Cowpokee

    Joined Jan 8, 2015
    153 posts, 38 likes
    MacGregor 26S, Goman Express 30
    US Kerr Reservoir
    I bought the motor several years ago from a guy that hardly used it. I am quite certain it came factory with the HT prop since it is a T9.9.
     


  5. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    903 posts, 273 likes
    O'Day 19
    US Littleton, NH Littleton, NH
    I don't know the answer to your question but a little context might help. I have a 19' mariner daysailer. They are often asking about the right engine size on the mariner web site. Most people have a 4-5hp motor but, the general consensus is that 2-2.5hp is enough. The mariner will collapse her transom with a 9.9hp. So, I would think you would have plenty of power with a 9.9hp on a 26' sailboat, no matter which prop.
    Sorry I can't answer your question directly. The high thrust props aren't meant to go faster, just have better 'bite' in the water so it is harder to resist them. Good for windy weather.
    - Will (Dragonfly)
     


  6. Crazy Dave Condon

    Crazy Dave Condon

    Joined Jun 8, 2004
    5,883 posts, 366 likes
    -na -NA
    US Anywhere USA
    @GBGraham
    Did this engine come from the U.S.? If so, can you recheck to see if the motor is a four stroke as federal requirements by 2006, only four stroke engines were permitted only but in other countries the two stroke was still available for market.
    @Cowpokee
    Are you at Steele Creek Marina. If so, I first came there when it was built selling sailboats as American Marine & Sail Supply. If so, is Martha gone for sure. No last name please. What 26 boat do you have? MacGregor?
     


  7. GBGraham

    GBGraham

    Joined Nov 10, 2017
    57 posts, 1 likes
    Hunter Legend 260
    Omega Gr Greece Epidavros
    Cheers for the reply Will. The boat I bought was advertised with a 15hp 4 stroke and I bid and bought less engine. The H260 is only CE plated for 7.5kw (10hp) and with being a bit of a dinosaur I like my 2 strokes.
    I bought the S/H Yamaha 9.9hp which yes should be well on top of it's job.
    In my sailing area ( 37 38 25 N 23 11 22 E) the unforecasted wind can soon whip up with no warning to bf6+ therefore I need something that will get me out of the way quickly and manoeuvre positively, hence the consideration of fitting a prop that will push me backwards nearly as good as forwards and not turn it into gas guzzler.
    Just in case we have anybody wondering why I didn't by a new FT9.9hp, one is there are no 2 strokes allowed here in Greece except for commercial boats ( that tells another story about 2T's) and the biggest reason is that here one would cost over 4100 euro's that's circa 4800 USD
     


  8. Rick Macdonald

    Rick Macdonald

    Joined Jun 2, 2004
    528 posts, 18 likes
    Hunter 23.5
    CA Calgary, Canada
    I know nothing about props but I bought a Thrustmaster from this website for the 9.9hp on my H23.5. It seemed to make a difference especially in reverse. It could be a usefull option regardless of what prop you use.

    It's 2 stainless plates that attach to the cavitation plate above the prop, forming a semi-circle around the prop. Other designs I've seen are complete circles.
     


  9. GBGraham

    GBGraham

    Joined Nov 10, 2017
    57 posts, 1 likes
    Hunter Legend 260
    Omega Gr Greece Epidavros
    Not sure of your question regarding the US . . . . Engine European, recreational craft ban mid 2000's stock items could sold after this period until stocks were exhausted. Now only for commercial use.
     


  10. Johann

    Johann

    Joined Jun 3, 2004
    178 posts, 24 likes
    Hunter 336
    US Pensacola


    Will Gilmore likes this.
  11. Benny17441

    Benny17441

    Joined May 24, 2004
    5,240 posts, 263 likes
    CC 30
    US South Florida
    Don't know about them marketing names suggesting that one prop will provide more power than another. Each boat and engine combination has one ideal prop and that is the one that will allow the engine to rev up to its maximum rated RPM without allowing it to go over. A quality prop will retain its shape in the water and will be more efficient. I don't think you will notice any significant improvement in acceleration or top speed from one of them props over a properly pitched stock one; after all improvements for a sailboat can be measured in fractions of a knot.
     


  12. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    903 posts, 273 likes
    O'Day 19
    US Littleton, NH Littleton, NH
    There are a number of variables in prop choice that will make a difference, depending on what you are looking to get out of a propeller.
    Working boats, like tugs use large diameter, wide 4 blade props pitched for slower speeds, race boats use narrow 2 blade, pitched for high speed. the amount of cup in the blade makes a difference as well as the rake of the blade. Confining the prop in a hoop tunnel losses less wash off the tips from rotation. This can be simulated by pitching the blades slightly aft at the tips. Trolling motors use props specifically designed for slow speeds and constant thrust.
    The propeller that comes stock with a motor is chosen for economic reasons and is intended to serve as a good general balance performer. For a relatively heavy displacement vessel with a lot of windage like a sailboat, high thrust over high speed is desirable. Choosing a propeller based on need makes sense.
    It is hard to know what is hype and what is worth the investment. Generally, I read the published comparison articles and the reviews of those who bought and used the product. If I'm not taking the time and have both (multiple) examples to compare for myself. Once the decision is made, it is the right decision until hard evidence to the contrary are presented. Most of the time, I'll never know, so why not assume I have it right and be happy?
    - Will (Dragonfly)
     


  13. SwitchintoglideIII

    SwitchintoglideIII

    Joined Feb 11, 2012
    229 posts, 27 likes
    C&C Mega 30
    CA Long Point, Lake Erie
    Have a 9.9 Mercury 2 stroke on my 30' er...
    Weighs in about 6000 lbs loaded for a week or so cruise. About 5700 lbs day sailing.
    Found the factory stock 3 blade prop was a decent performer getting pushing hull speed near or at WOT. Was absolutely ineffective in reverse, maneuvering in the marinas.
    Purchased a High Thrust 4 blade prop from Solas.....very impressed with the reverse response and control now. It performs better and with less effort forward from trolling thru mid range RPM. At WOT it works well, but at slightly less SOG then the stock prop....and not quite full hull speed.
    I keep the stock one on board as a spare, but really like the performance of the four blade high thrust prop by Solas.
    Hope this helps some....

    Regards.
     


  14. Crazy Dave Condon

    Crazy Dave Condon

    Joined Jun 8, 2004
    5,883 posts, 366 likes
    -na -NA
    US Anywhere USA
    GBGraham;
    You responded the engine is a 9.9 vs 15 hp.
    Transoms due to construction on sailboats only are rated up to 10 hp max in the U S. Anything more is too much. First with a 15 hp, the bow will raise up basically plowing against a wall of water slowing you down which requires throttling down. Anyone reading this will know what I am talking about. So 10 hp on the transom is max hp for this boat. In addition the construction is not like that of power boats which have much higher hp engines. First a power boat hull is a planning hull which basically rides on top of the water; thus, a more substantial construction of the transom to accommodate higher hp engine. As for the sailboat hull, it is a displacement hull which glides thru the water which does not require the higher hp engines. So the first comment of plowing thru the water and to back down will allow the boat to reach max speed for that paticural hull when the bow comes back down on a sailboat. As for construction of sailboat hulls that sport a transom mount engine, the manufacturers went with the thumb or rule of 10 hp being max on the transom due to construction.

    Those power sailors have two hulls in one with a higher hp engine on the back but the transom is more substantial for those style boats.

    As for a four prop blade, concur give you more stability in reversing but until water flow over the rudder in reverse takes over for steerage, more blades in reverse tends to help against prop walk to the left. There are ways to overcome that when reversing the boat backwards into a slip. In addition, starting in 2006, all engines had to be four stroke for new ones basically due to EPA rules but the two stroke new engines were basically grandfathered in or can still be used.
    As for fuel, I hope you are using straight gas where you are and not the ethanol, corn crap as I call it, in the engine.
     


    Will Gilmore likes this.
  15. GBGraham

    GBGraham

    Joined Nov 10, 2017
    57 posts, 1 likes
    Hunter Legend 260
    Omega Gr Greece Epidavros
    Thanks Johann passing that link on to me. and thanks to walt also if he is still on the forum, I feel a lot of effort has gone into this exercise.
    Benny, I'm not absolutely sure your statement is correct for my question. The standard prop surely has to be a happy medium, a jack of all and master of none?
    What I am looking for will probably be better in some range and poorer in other. I'll ask the question, with my engine being a twin cylinder, 2 stoke, it's data I presume will be different because of firing every stroke than every other as a 4 stroke would?
     


  16. FastOlson

    FastOlson

    Joined Apr 8, 2010
    873 posts, 57 likes
    Ericson Yachts Olson 34
    US Portland, OR Portland OR
    Watch out for comparisons using the phrase "high thrust". When we used a Yamaha 4-stroke 10 hp High Thrust for a decade, it was the only such OB on the market with a different final gear ratio. It swung an 11 3/4" three blade prop, and the final ratio was almost 3 to 1. Usual ratios for outboards are about 2 to 1.

    This was an engine model specified for displacement hull vessels. It worked really well, powering our 26 footer @ 6 kts, at 1/2 gallon/hour fuel usage, all day if need be. Powering against a steep chop in a narrow channel was easy also.
    Before that we had a Honda 10 with a three blade prop that I had de-pitched for our boat. Worked OK, but lacked torque in a chop or a head wind. (We sail on a river and there are a number of areas where the channel is too narrow to make sailing practical.)

    So choose your prop for your top speed, but just be aware that gearing is actually more important.
     


  17. walt

    walt

    Joined Jun 1, 2007
    3,074 posts, 277 likes
    Macgregor 26S Hobie TI, Capri Coronado 15
    US Denver, Colorado
    Here was another discussion on this https://forums.sailboatowners.com/index.php?threads/high-thrust-props-and-sailboats.186879/

    Ive just come to the conclusion that for sailboats, the high thrust mostly improves the reverse drive.. but you have to be careful with this as it can REALLY improve the reverse thrust and the outboard is mechanically much better set up for forward thrust. The larger the boat and the smaller the hp.. also becomes more important. I would guess 10 hp on most 26 foot boats is somewhat in the area where its not that important but thats really mostly opinion. Not a lot of expense to just try a different prop however.. who knows. Plenty of people like them, others think they dont matter. The fact that you cant find a common consensus should mean something.
     


    Last edited: Dec 18, 2017
  18. GBGraham

    GBGraham

    Joined Nov 10, 2017
    57 posts, 1 likes
    Hunter Legend 260
    Omega Gr Greece Epidavros
    Thank you SwitchintoglideIII, Yes, just what I needed, first hand info and it does really help. Have you any info on the dia and pitch please.
    The only one I can find in the UK is this 3 blade High Thrust prop upload_2017-12-18_17-8-15.jpeg
    9 3/4 x 8
     


  19. GBGraham

    GBGraham

    Joined Nov 10, 2017
    57 posts, 1 likes
    Hunter Legend 260
    Omega Gr Greece Epidavros
    Thank you walt, "Not a lot of expense to just try" Mmmmm may be cheaper at your side of the pond but this
    is equivalent to about 135 USD over in the UK and I don't know anybody that's used this.
    upload_2017-12-18_17-13-35.jpeg
     


  20. GBGraham

    GBGraham

    Joined Nov 10, 2017
    57 posts, 1 likes
    Hunter Legend 260
    Omega Gr Greece Epidavros
    crazy-dave-condon. The reason I opted out of buying the boat with a 15hp was because it was only plated for 10hp. and having a 15hp could of complicated an insurance claim for any reason that may occur and I had already decided about the stress factor to the mount.
    No corn crap out here in Greece and back in the UK the last producer has shut it's doors thank goodness.
    FastOlson
    Impressive figures, I would be happy with those. I did realise the gear ratio's this is why I need something concrete before I purchase.

    Thanks to all for your replies so far
     


    Last edited: Dec 18, 2017

Hunter faucets and parts
Replacement fixtures, hoses, sprayers, washers, and more.
Hunter props, shafts, struts, and cutless bearings
Power train parts for most every Hunter model, most in stock for fast shipment.
Hunter replacement stanchions
Replace for safety and appearance
Deck fill caps for most Hunter sailboats
In stock, these caps will fit most boats newer than 1990