too much prop?

I have had my boat for three weeks now. I have tested out running with 1, 2, and 3 people with two props and noted the RPMS and speeds.<br /><br />Boat is 14'11" Deep V that weighs about 600 lbs.<br /><br />With me and gear (200+50) I get 6200 RPMs fully trimmed at 29.3 mph. Very slight hint at cavitation in sharp turns, the boat does not fall of plane until about 5-7 mph, the hull does not slap waves in chop and the boat will troll down to less than 1 mph. This is by my standards excellent. The only thing that I want to improve on is hole shot. It takes about 8 seconds to plane with me and some gear. This is a 9.25x12 pitch aluminum prop that came with the motor. It will also plane with two people in about 13 seconds and get up to about 25 mph. My conclusion is this is a good setup for one person, or two average people and minimal gear. I wonder why it strugles with the plane and then gets RPMS to just above the recommended max of 6000. Also the 12 won't plane max load of 750 lbs, so it seems fairly obvious that a 12 pitch is towards too much prop.<br /><br />My guess was that an 11 pitch would solve this, but I was surprised. I purchased a solas saturn stainless 10x11 pitch prop. This causes a small loss of top end speed of about 2 mph. It will plane 1 or two people slightly faster than the 12. It will also plane 3 guys of total weight of 750 lbs which is max rating, but it takes excessive time and requires the guy in front to lean forward. It gets 23 MPH if it planes. Interesting that it will not troll down to less than 2 MPH which is a huge black mark in my book. I also think the prop is a bit off true as it wants to vibrate at RPMs under 800.<br /><br />My conclusion is that I probably need two props one for heavy loads and one for light to average. The 11 pitch stainless solas is off the boat and not likely to go back on. <br /><br />There is a 9 3/4 x 9 7/8 OEM Honda prop availalable, but not an 11. Solas makes an 9 7/8 x 11 aluminum. Thinking that I will purchase the OEM 9 7/8 prop and use it for heavy loads and use the 12 when fishing by myself. <br /><br />It is possible that the SOlas 11 pitch aluminum would be a good all around prop? I am a little gunshy on another Solas, but don't want to jump to conculsions. This is aluminum and a different design than the stainless I bought. I don't normally go out with three people, but I will be taking the parents out in August and will have to travel about 10 miles to the destination. My overall concern is that I want to have a prop on that will plane the boat which seems to push me to the 9 7/8ths. I read several times that diameter does not matter much, but wonder if this is a case where it might be a factor. Thanks in advance for any thoughts on this.

Re: too much prop?

Personnaly, I think that is a bit too much load for a 30 hp motor to push. You have a 30hp right?<br /><br />Maybe a 4 blade prop?

Re: too much prop?

Your prop size indicates you have a 25 or 30 Honda.<br /><br />Can you supply more details of revs with the Solas 11" stainless with all loads? The fact that your troll speed has increased indicates that the Solas has larger blade area than OEM prop- is that correct?<br /><br />I have used a couple of Solas props and they have very poor leading egdes - designed for life digging up sand and not performance. Given that you were overreving on 12 pitch, its not surprising that one up speed dropped when you ran 11 pitch.<br /><br />If you can accept more ventilation in turns, you should lift the motor as this will increase speed and revs and improve hole shot. More cupping (prop rework and blade thinning on the Solas) will also allow you to run higher motor mount positions. If very low troll speed is really important, get a worn out prop (or trim down the diameter of a damaged prop) so you have much less blade area. Whilst it will cost you, it may even be possible to rework the cut down prop and to make it perform properly. I once damaged a prop and decided to trim the blade area to make into a spare. I was amazed that it was as good as a new one in WOT speed and improved hole shot by allowing more revs while getting on plane. If you operate in areas where you are very likely to damage the prop, then my prop rework recommendations should be disregarded.

Re: too much prop?

Originally posted by roscoe:<br /> Personnaly, I think that is a bit too much load for a 30 hp motor to push. You have a 30hp right?<br /><br />Maybe a 4 blade prop?

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Max rating is 40 HP, so I am not that far off at 75% of max. I believe it is pretty fair to say that when running max load the boat is underpowered, but it does pretty good until the load gets over 600 lbs which would put the total close to 1500 with the hull and motor included. <br /><br />I pretty much have to deal with this as there are some HP restrictions where I like to go sometimes. I won't often carry three people, so I am thinking the OEM 9 7/8 pitch will get me by when I have max load. The Solas Saturn 10x11 is very close to workable in terms of planing the full load, so I think dropping one more will help in a 3 blade.<br /><br />I have considered a 4-blade and this might work. I have no experiance with these guys, so I don't know how it might behave. SOunds like it should improve hole shot, but errode on top end. I expect this is similar to what would happen with dropping down to a 9 7/8 three blade. I do worry about loosing the ability to creep along at less than 1 mph with a 4 blade.

Re: too much prop?

Originally posted by nevd:<br />[QB] Your prop size indicates you have a 25 or 30 Honda.<br /><br />Can you supply more details of revs with the Solas 11" stainless with all loads? The fact that your troll speed has increased indicates that the Solas has larger blade area than OEM prop- is that correct?<br />

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The solas saturn is 10x11 and the oem is 9 1/4 x 12. I did not write down all the results, but I can tell you the max RPMs with the solas were very similar to the oem. I expected that the 11 would produce more RPMs than the 12, but not the case. Solas gives a slightly better hole shot, but not as much as improvement as I thought it would have. You are right about the edges being very smooth. Your info helps me understand why I don't like the solas prop much. Improved hole shot was the primary objective and maintaining slow troll is also important. I am less concerned about top end speed, but it matters some.<br /><br />I could move up a tad with the motor, but I do like how it sits now and would rather solve with a prop. I found that I can trim to a certian point and both RPM and Speed do not increase any more. At that point, a very sharp turn could produce cavitation, and a moderate turn produces rather minor prop slip. If I back off trim a tad from there, my RPMs drop to 6000 and even sharp turns don't cause a bother. <br /><br />Sounds like the I should look for a prop that is close to the 9 1/4 diameter that I have now in a 10 or 11 pitch with a good biting edge. I was probably right thinking 11 is the number, but the increased diameter and soft edges on the blade of the solas are not good for my needs.<br /><br />Thanks much