Getting on the plane efficiently

[Andrew Leigh]

This is a really basic question<br /><br />It may well be my imagination but other boats appear to get on the “plane” a lot quicker than mine. On a 17’ bow rider having a shallow V hull with a 115 Rude attached I achieve a WOT of 5500 so the motor appears to be running right. It is propped correctly at 17”, this I have checked on this forum.<br /><br />With four largish adults in the boat I battle to get on the plane quickly.<br /><br />On the instrument panel I have what I call an “attitude gauge” it appears to show the engines attitude or angle to the hull (what is the real name of this gauge?). This gauge is much like a gas gauge with it’s markings so think of the readings as such as I try explain.<br /><br />When on the boat is on the plane it measures between three quarters and full. At this position she is sweet and I achieve my max WOT of 5500 at altitude and 6000 at sea level. So I figure that this must be the optimum setting for the hull and accordingly it stays set there. When getting the boat on the plane the bow lifts considerably, the vector analysis I am sure would reveal a resultant vector of about 30 degrees perhaps wasting energy. Not sure as I am always in the boat.<br /><br />So how do you guys do it? Do you vary the tilt during the process of getting on the plane? What am I doing wrong? I probably should have timed how long it takes as my perception may be incorrect and or my expectations too high.<br /><br />Cheers<br />Andrew

 

[Boomyal]

Re: Getting on the plane efficiently

Andrew, I suspect a good part of your problem is the 6000' altitude. I'm sure that you have properly jetted for that altitude but still the air is pretty thin up there. Four large adults only exacerbate the problem.<br /><br />If you have power trim, using it while trying to plane would help. Not sure what your guage is but I would suspect it is a trim meter. It's indication should not vary with the boats state of plane, only with the relationship of the motor to the boat.<br /><br />Undoubtedly you have witnessed the trim tab debates here. I would strongly suspect that a set of Smart Tabs would work wonders for you. I think that 115 hp on a 17'ftr would be more than adequate with a little help.

 

[roscoe]

Re: Getting on the plane efficiently

Lower the motor all the way down, then try to get on plane. It should be quicker.<br />After getting up on plane, trim the motor up to the sweet spot you mentioned.

 

[wvit100]

Re: Getting on the plane efficiently

Your trim isn't something you set and forget about. You've got the motor trimmed out which pushes propellar down and the bow skyward as you try to accelerate. Most of the time when you idling around or taking off you should have the motor trimmmed down all the way then raise the trim to lift the bow after the boat comes up on plane. You also vary the trim depending on what you doing and the water conditions. The boat will handle choppy water better with the trim down even on plane.

 

[Bondo]

Re: Getting on the plane efficiently

Add Smart Tabs..........

 

[umblecumbuz]

Re: Getting on the plane efficiently

Bondo's hit it.<br /><br />In nearly every case like yours, a set of good trimtabs is the best fitment you can make.<br /><br />Big snag with Smart tabs is a following sea, when they can be a pain. Answer is just to go faster!

 

[sangerwaker]

Re: Getting on the plane efficiently

No one has mentioned prop venting or porting? I would try that first. Virtually no cost involved. What type of prop are you runnung now? Aluminum or stainless?<br /><br />As mentioned, you will get your best "holeshot" with the trim all the way down. After getting on plane, adjust the trim to your liking.

 

[Andrew Leigh]

Re: Getting on the plane efficiently

Thanks guys,<br /><br />The problem is not getting onto the water enough to experiment and to talk to other boaters.<br /><br />You have all confirmed my suspicions after my Sunday outing. After thinking about it on Sunday evening and some simple vector analysis I came to the same conclusion but was unsure of the drag effect on the hull. Most my power is being directed in an inefficient direction.<br /><br />Boomyal yup would probably be the "trim meter". As a matter of interest at sea level I actually need a 19" prop due to the power gain.<br /><br />My stern area does not allow for the fitting of smart tabs. When I bought the boat it had Hydrofoils fitted to the lower unit, probably as a result of being impossible to fit trim tabs.<br /><br />Sangerwalker "prop venting or porting" please explain? Did a bit of an internet rearch but did not turn up anything really informative, will keep on looking though. The prop is aliminium and in very good condition (boat seldom gets used).<br /><br />Thanks again<br />Andrew

 

[ufm82]

Re: Getting on the plane efficiently

Prop venting or porting is the practice of drilling holes in the barrel of the prop at the base of the blade- it allows exhaust gases to bubble out of the barrel take-off. That allows the prop to spin faster and give you a better holeshot. Some boats can benefit from this and some do not. <br /><br /> By the looks of the thread, I think your biggest problem may be simply trim. Trim angle should be adjusted all the time, depnding upon load and conditions. When taking off, trim the engine completely down. Neutral trim is having the lower unit and the hull at a 90° angle. Trimmed down means the lower unit tucks towards the transom and trimmed up means away from the transom. Trimming down forces the bow down- trimming up raises the bow. If you trim all the way down and accelerate, the bow shouldn't rise so high that you plow- you should come up on plane pretty quickly. Once you get up, you will then trim up until you find that "sweet spot" where RPM and speed start to increase without any input from the throttle. As you trim up, the engine will begin to push down on the rear of the hull, forcing the bow up. With the speed you now have, this decreases the wetted surface of the hull and that means less drag. Thus, better speed and better fuel economy. When you slow down, you will again need to trim down or porpoising can occur- that's when your bow bounces up and down and can get quite annoying. <br /><br /> Learning how to use the trim is free and takes no time. Just use it as it was meant to be used. <br /><br /> The comment about Smart Tabs is valid- I just bought a pair for a different reason but they are effective in your situation. They can be a real benefit when you have other influences like yours.<br /><br />UFM82

 

[sangerwaker]

Re: Getting on the plane efficiently

Venting or porting a prop is adding holes behind each blade to allow some exhaust gas to escape and the motor to "rev up" before the prop bites. Works kind of like a stall speed converter on a drag car.<br /><br />Greatly enhances holeshot, but has no ill effects on top end. I'm looking for some links for you now. Just be sure to start small with the holes. Once you make them too big the boat will not even take off. Start with 3/16" or 1/4". You can always make them a little larger.<br /><br />try these<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=010317#000000 <br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=17;t=038114#000004 <br /><br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=search_tng&d=results&record=2453458-143927-BMKY

 

[ufm82]

Re: Getting on the plane efficiently

Whoa there big fella! There's no reason to start drilling holes in a perfectly good prop.<br /><br /> Read his description sanger- he's trying to take off with the engine trimmed in the cruise position. Any boat trimmed in that position is going to stick the bow in the air and plow along initially. With a load, and a not so overly strong engine, he's not going to make it. He could drill holes in his prop and if he doesn't trim it right, it won't make a bit of difference.<br /><br /> Andrew- trim it down all the way and then punch it. Once the bow breaks over, start trimming up until you hit that sweet spot. <br /><br />UFM82<br /><br />Drill it down the road if you need to- I doubt a 115 is going to benefit all that much though.

 

[sangerwaker]

Re: Getting on the plane efficiently

A 115 will benefit GREATLY from venting. Had a Evi 120 on my last boat. Makes a HUGE difference. Venting a prop will often times improve holeshot performance on a two stroke outboard. Sounds to me like Andrew's problems are multifold.<br /><br />First, experiment with the trim. As mentioned, it's not a "set it and forget it" kind of thing. Always trim down fully when going from a stop aor idle to plane for best performance.<br /><br />If, after doing the above, you are still unsatisfied with the performance, try the venting. It does not affect performance whatsoever on any other aspect than hole shot.<br /><br />Check the last link I provided above and see for yourself. There are a lot of topics lkisted on venting. ALL of them are positive in nature.

 

[umblecumbuz]

Re: Getting on the plane efficiently

And to add to Sanger's advice - you can always fill the holes in the prop back in, if you find they're detrimental.<br /><br />No permanent harm done to the prop.

 

[Boatist]

Re: Getting on the plane efficiently

I have helm controlled trim tabs and could and could bring the boat up on plane <br />with no bow lift at all. However I usually bring boat up on place with out useing the trim tabs. <br /><br />To bring it up on plane with out trim tabs trim your motor all the way in. <br />Advance the throttle to near full throttle and as the Boat comes up on plane <br />pull the throttle back to the rpms and speed you want. <br /><br />On My boat I advance the throttle to full throttle and watch the rpm guage <br />when the RPMs reach 3000 I pull the throttle back slowly to keep it near 3000 rpms. <br />This get the boat up on plane fast with very little bow rise. <br />When I reach the speed I want I then trim motor for best ride. <br />Actually on my boat when I reach speed I want I use trim tabs to trim for best ride <br />then trim motor for best speed and fuel use.

 

[Andrew Leigh]

Re: Getting on the plane efficiently

Hi guys,<br /><br />have read all the posts in the links, thanks sangerwalker.<br /><br />At his stage the lack of holeshot performance appears to be my poor boatsmanship due to the incorrect use of the power trim. I like to have things to work as designed before modifying as I prefer to treat the cause and not the symptom.<br /><br />So i'm taking all the advice offered, firstly will try get onto the lake this weekend and experiment. Once I understand the true holeshot performance of my rig I will be able to say if it is adequate or not.<br /><br />However, I love tweaking things and sangerwalker has made me curious about prop drilling. I will start experimenting on this when my rig is functioning to specification.<br /><br />Some more clarification required. On my trim meter would it be correct to assume that on the halfway marker that this is neutral trim? I can measure it I suppose.<br /><br />UFM82 you intimated that trimming down (below neutral) would assist holeshot, did I read you correctly?<br /><br />Thanks again guys<br />Cheers<br />Andrew

 

[sangerwaker]

Re: Getting on the plane efficiently

Yes, trim ALL THE WAY DOWN. Trim it down until it won't go any lower and note where that is referenced on your gauge. Use the gauge as a reference point. The middle of the gauge is not necessarily neutrsl trim. There is an adjustment on the trim sending unit for that, but that's a whole other topic.<br /><br />My suggestion would be to go out to the lake and play around a little .....have some fun! Trim completely down, take off, and once on plane, experiment with trim and throttle settings.

 

[wvit100]

Re: Getting on the plane efficiently

Half way is not neutral. Half way on my boat is more than you would want when running at full speed with two people in the boat. Half way on mine is what it shows at max trimmed up position, any more than that requires that you hit the trailer button which gets you into the tilt part of the system. Full up is the trailer position on mine.<br /><br />You can tell what's going on when you start to play with it on the water. Your trying to over analyize the workings of the tilt/trim, it's very simple. You must be an engineer.

 

[mattttt25]

Re: Getting on the plane efficiently

people hit on your answer in various places.<br /><br />like stated, you don't set and forget your trim. it should be down or at least at a neutral setting when getting out of the hole. once on plane, trim up until you find a good setting for the conditions and load.<br /><br />try this out and get comfortable with it. then, if you have performance issues or questions, ask them. but don't go slapping tabs and drilling your prop just yet.

 

[rogerwa]

Re: Getting on the plane efficiently

I agree that 99% of the problem is most likely inappropriate use of trim. It should be noted as well that weight placement will also effect planing. If you have 4 250lb'ers in the back of a 17ft boat you will have problems planing. If trim does not impact your problem, try moving weight up front, at least temporarily.

 

[lenny2113]

Re: Getting on the plane efficiently

I was puzzled for a few minutes why my first boat 17ft Galaxy does not get on plane. I looked back at the "rooster tail" (wake) and happened to remember that I had my 225lb friend with me. <br />As soon as I asked him to come forward and stay in the middle of the boat, I was up on plane in seconds . There it was - my weight distribution lesson.