explain the term planing

[husaburg560]

I'm fairly new to boating and have heard the word planing used before. How do you know when your boat is on plane? thanks

 

[waterone1@aol.com]

Re: explain the term planing

This one has been covered on here before. From stop, as you speed up, the boat will "bow rise" out of the water, at some point as the speed increases the bow will come back down as the transom of the boat rises. Once the transom is riding high and the bow is level the boat is said to be "on plane". With a particular hull design, it means that the minimum surface area of the hull is in contact with the water.

 

[inthesticksnow]

Re: explain the term planing

Originally posted by husaburg560:<br /> I'm fairly new to boating and have heard the word planing used before. How do you know when your boat is on plane? thanks

I’m a Newbie here, and because what goes around comes around, I will respond as best I can in layman’s terms for you. <br /><br />With your drive trimmed DOWN, when your boat picks up speed, the hull (that’s you and the boat) starts to rise and level out (bow comes down), because of the thrust generated by the prop behind you. When you are “planing” the smallest portion of the bottom of your hull is actually in the water. You are “up”, “skimming”, rather than “plowing”, as you would be if just idling along with the entire weight of your boat resting on the water. The shape of your hull (usually a “V”), if not under speed, will just float as it is slowly pushed along, weighted down in the water like a raft. While under speed, however, the water pushing up against the “V” shape of your hull will force the boat up, away from the water. At a certain speed, the water pressure pushes the hull up… hence “planing”. This is the least amount of drag and the optimum way to travel, but you will need to power your boat to a certain MPH top achieve this. <br /><br />Once “up” (you will feel this – bow will be down) you will then need to work on “trimming” your drive slightly UP, because once you reach a planing level (the boat is up) the drive needs to be raised slightly else your bow will NOW be pushed down unnecessarily beyond optimum. Again, due to the force behind you (the prop), which has brought you UP to planing speed, if not slightly raised therafter, will NOW push your bow down. So you need to compensate between what brought you up (trim down, higher speed) and what will keep you there (trim up somewhat, to keep the bow from being forced down.) This is a “feel” thing.<br /><br />Once up, you need to find a balance. That’s another discussion… I will tell you to search the mechanics of this.

 

[gutshot grouper]

Re: explain the term planing

Planing is the speed at which a hull no longer displaces the mass of water equal to the gross weight of the hull and contents.

 

[stevens]

Re: explain the term planing

In other words, planing occurs when the forward thrust of the engine is sufficient to push the gross weight of the boat up on top of the water, not just through it.

 

[jlinder]

Re: explain the term planing

Something that no one has mentioned is that when you get on plane the efficiency (speed) of the boat goes way up.<br /><br />For example, when I am turning about 2200 RPM I will be going at about 14 MPH. If I raise it to 2400 RPM the boat will get on plane (about 6 seconds) and will be moving at about 22 MPH.<br /><br />About a 10% change in power and about a 60% change in speed.<br /><br />Go out and play. Slowly increase your engine RPM and wait for about 10 seconds. At some point you will do notice the bow coming down and feel the boat speed up noticably. At that point you are on plane

 

[husaburg560]

Re: explain the term planing

Thanks for answering my question. I really enjoy this boating site.

 

[umblecumbuz]

Re: explain the term planing

Dead simple explanation coming up:<br /><br />Skim a stone across the water - that's planing. Pull it through the water - that's displacement.<br /><br />Which is easier, and therefore faster and more fuel-efficient?

 

[steelespike]

Re: explain the term planing

When speaking of just off plane and being just on plane planing is generally more efficient.<br /> But a boat designed to run at displacement speeds is most efficient.We are talking slow<br />about 6 mph. But mpg is can be as much as 30+ miles per gallon.

 

[Realgun]

Re: explain the term planing

Steel spike those hulls genrally have a big bump area in front then a long slope to the back correct? Then you olny pushing a small amount of water down and it flows up the hull to get out a long way. This tends to push the boat forward.

 

[QC]

Re: explain the term planing

Steel Spike is correct. I have seen small planing hulls get ovcer 10MPG at idle speeds too(usually at or below true hull speed).<br /><br />My undertsanding of efficient planing is exceeding your bow wave speed. Technically, as soon as the water starts breaking away cleanly from the hull at the transom, the boat is planing. Gut Shot Grouper's explanation is probably even more correct. The effcient points are somwhere above the that.

 

[fireman57]

Re: explain the term planing

Stillfishing, I like your explanation. Cuts right through the BS and anyone can understand it.

 

[umblecumbuz]

Re: explain the term planing

Thanks, Fireman,<br /><br />Always was a simple guy!