E.Q. Harbor Service & Sales
265 Cornet Bay Road
Oak Harbor, WA 98277
www.eqmarine.com
(866) 679-4783
265 Cornet Bay Road
Oak Harbor, WA 98277
www.eqmarine.com
(866) 679-4783
Please visit Arima's web page for specific model information.
Arima boats were developed in the late 1970's by Mr. Arima to address the needs of that era; interestingly enough, they're much the same again today. "Back then" fuel prices had climbed, folks were filling up on odd and even days, and no one wanted a boat that used a lot of fuel or the vehicle necessary to tow a large boat. So Deja Vu...here we are in 2010 and few want a boat that uses a lot of fuel and many folks don't have a large tow vehicle either.
What makes the Arima different? That is, what makes it an Arima rather than a clone of a typical mass production boat? What makes it different quite frankly is in the initial concept; one of the very first things a boat designer has to decide is what the typical (normal) speed will be for the boat s/he's working on. That's because with boats you can't really have it all. Due to the nature of the beast there are just some things that require compromises.
Speed is one of them since it totally dictates the possible shape the hull can have to achieve the desired speed. There's a lot of math and design considerations behind this but in simple terms you can't get a boat (we're talking about trailerable power boats here) that will comfortably cruise at 30 knots (meaning in other than flat water) and also comfortably work at 10 knots. Certainly not the typical deep-v production hull that requires about 3 times the square root of the waterline length (in knots) to plane properly; so for a 21-footer that's 3 * 4.3 (assuming a 19-foot waterline length), which is 13 knots, anything less than that results in the stern settling and the bow coming up (also loss of forward visibility and economy).
The Arima was designed for Puget Sound and the goal was for a safe boat that would require much lower horsepower than a deep-v hull. That's why an Arima 21 runs decently on 90 horsepower while 175 to 200 horsepower would be the "norm" for the same size deep-v hull.
There are no secrets when it comes to economy with a planing hull...the faster you want to go and the more weight you want to move the more fuel you'll use. It's pretty straight forward math. There is a "bump" in the fuel burn curve of a deep-v hull from just above hull speed (1.34 times the square root of the waterline length) until the boat is on a true plane (about 3 times the square root of the waterline length), in this area the boat uses fuel faster than it gains speed and economy suffers.
The easiest shape to plane is a flat board, as evidenced by riding a skim board at the beach. The most difficult would be a knife edge. Given that, a flat bottom boat is easier to plane than a deep-v boat. If it was just that easy we'd all have flat bottom boats if we were after the easiest to plane hull. Unfortunately speed and comfort come into play and we find that a flat bottom boat can be mightly uncomfotable while a deep-v hull can cruise though fairly rough conditions with a greater degree of comfort. So the compromise is between what one desires for speed, what is necessary for a chosen cruising speed, and what is necessary for power to achieve that speed (there are lots of other factors too).
The Arima takes a solid middle ground in attempting to blend a reasonable speed with modest power. I usually peg the "normal" cruise speed of an Arima hull at 20 knots. Of course, Arima boats out there in use on the water run at a lot of other speeds but 20 knots is a good indicator of what the hull was intended to do. If one is honest about this it means that if, as a normal course of operations, one intends to operate the Arima at 30 knots and above all the time that the "wrong" hull has been chosen for the application. [There are always exceptions and situations where one can argue the point but that's not what I'm trying to convey here. The simple fact is, if you're not running on a flat lake choosing the Arima hull for 30 knot-plus work is not making the best choice unless there are other overriding factors.]
What sets the Arima apart (from the typical mass produced boat) is that there is not a lower speed at which the boat won't operate comfortably. Not so with the typical deep-v hull; they most certainly have a lower limit to their comforatble speed range (usually about 3 times the sqaure root of the waterline length). So, if you're out in garbage water conditions and you want to do 10 knots to stay comfortable the Arima will do it well, the deep-v not so well, or not at all (due to loss of visibility and discomfort). The arguement then is usually that the deep-v can stay up and running at higher speeds but this isn't the case unless you're a glutton for punishment. At some point water conditions will dictate that all small boats slow down. And even though a deep-v hull might cleave the water and not bang you can't get rid of the g-forces; the faster you run the more g-forces come into play. The reason most folks stand up to run a deep-v hull in rough conditions is so that one's body can act as the shock absorber it needs to become.
You wouldn't choose to do this in an Arima, it would be extremely uncomfortable. While the deep-v is a stand up and go boat, the Arima is a sit down and find a comfortable speed boat.
In a nutshell, those are your choices. Bigger power, high speeds, less fuel economy, and the ability to run harder (to a point) in rough conditions (the deep-v hull); or lower power, slower speeds, higher fuel economy, and the ability to slow down in rough conditions for comfort and economy (the Arima and other moderate-v boats).
Which is best? Ah, that we can't help you with! Only you know what you're most likely to be happy with and what speed, performance, or fuel economy you demand from your boat. I would never portray the Arima (or any other boat) as "the answer" to every boating situation, that's just simply not true (and can't be). For many folks the Arima is a great choice; it's roomy, it's safe, it's honest, it requires modest horsepower, it has good fuel economy, and since they're still building them as they always have it's a timeless sort of boat not affected by fads.
Happy boating!
What makes the Arima different? That is, what makes it an Arima rather than a clone of a typical mass production boat? What makes it different quite frankly is in the initial concept; one of the very first things a boat designer has to decide is what the typical (normal) speed will be for the boat s/he's working on. That's because with boats you can't really have it all. Due to the nature of the beast there are just some things that require compromises.
Speed is one of them since it totally dictates the possible shape the hull can have to achieve the desired speed. There's a lot of math and design considerations behind this but in simple terms you can't get a boat (we're talking about trailerable power boats here) that will comfortably cruise at 30 knots (meaning in other than flat water) and also comfortably work at 10 knots. Certainly not the typical deep-v production hull that requires about 3 times the square root of the waterline length (in knots) to plane properly; so for a 21-footer that's 3 * 4.3 (assuming a 19-foot waterline length), which is 13 knots, anything less than that results in the stern settling and the bow coming up (also loss of forward visibility and economy).
The Arima was designed for Puget Sound and the goal was for a safe boat that would require much lower horsepower than a deep-v hull. That's why an Arima 21 runs decently on 90 horsepower while 175 to 200 horsepower would be the "norm" for the same size deep-v hull.
There are no secrets when it comes to economy with a planing hull...the faster you want to go and the more weight you want to move the more fuel you'll use. It's pretty straight forward math. There is a "bump" in the fuel burn curve of a deep-v hull from just above hull speed (1.34 times the square root of the waterline length) until the boat is on a true plane (about 3 times the square root of the waterline length), in this area the boat uses fuel faster than it gains speed and economy suffers.
The easiest shape to plane is a flat board, as evidenced by riding a skim board at the beach. The most difficult would be a knife edge. Given that, a flat bottom boat is easier to plane than a deep-v boat. If it was just that easy we'd all have flat bottom boats if we were after the easiest to plane hull. Unfortunately speed and comfort come into play and we find that a flat bottom boat can be mightly uncomfotable while a deep-v hull can cruise though fairly rough conditions with a greater degree of comfort. So the compromise is between what one desires for speed, what is necessary for a chosen cruising speed, and what is necessary for power to achieve that speed (there are lots of other factors too).
The Arima takes a solid middle ground in attempting to blend a reasonable speed with modest power. I usually peg the "normal" cruise speed of an Arima hull at 20 knots. Of course, Arima boats out there in use on the water run at a lot of other speeds but 20 knots is a good indicator of what the hull was intended to do. If one is honest about this it means that if, as a normal course of operations, one intends to operate the Arima at 30 knots and above all the time that the "wrong" hull has been chosen for the application. [There are always exceptions and situations where one can argue the point but that's not what I'm trying to convey here. The simple fact is, if you're not running on a flat lake choosing the Arima hull for 30 knot-plus work is not making the best choice unless there are other overriding factors.]
What sets the Arima apart (from the typical mass produced boat) is that there is not a lower speed at which the boat won't operate comfortably. Not so with the typical deep-v hull; they most certainly have a lower limit to their comforatble speed range (usually about 3 times the sqaure root of the waterline length). So, if you're out in garbage water conditions and you want to do 10 knots to stay comfortable the Arima will do it well, the deep-v not so well, or not at all (due to loss of visibility and discomfort). The arguement then is usually that the deep-v can stay up and running at higher speeds but this isn't the case unless you're a glutton for punishment. At some point water conditions will dictate that all small boats slow down. And even though a deep-v hull might cleave the water and not bang you can't get rid of the g-forces; the faster you run the more g-forces come into play. The reason most folks stand up to run a deep-v hull in rough conditions is so that one's body can act as the shock absorber it needs to become.
You wouldn't choose to do this in an Arima, it would be extremely uncomfortable. While the deep-v is a stand up and go boat, the Arima is a sit down and find a comfortable speed boat.
In a nutshell, those are your choices. Bigger power, high speeds, less fuel economy, and the ability to run harder (to a point) in rough conditions (the deep-v hull); or lower power, slower speeds, higher fuel economy, and the ability to slow down in rough conditions for comfort and economy (the Arima and other moderate-v boats).
Which is best? Ah, that we can't help you with! Only you know what you're most likely to be happy with and what speed, performance, or fuel economy you demand from your boat. I would never portray the Arima (or any other boat) as "the answer" to every boating situation, that's just simply not true (and can't be). For many folks the Arima is a great choice; it's roomy, it's safe, it's honest, it requires modest horsepower, it has good fuel economy, and since they're still building them as they always have it's a timeless sort of boat not affected by fads.
Happy boating!
 |
