Wednesday, March 28, 2012

Hydraulic Steering

Dyna-Ski Boats normally have hydraulic steering.  On many boats hydraulic steering is an expensive option.

Hydraulic steering is often called "power steering" which it is not. Hydraulic steering does make the boat with it on much easier to steer but there is no power assist like a vehicle has unless the hydraulic steering has the power assist option.

Hydraulic steering makes it much easier to steer the boat that has hydraulic steering on it vs a boat that does not have hydraulic steering.

The smaller the motor size the less the need for hydraulic steering.  Bigger motors and faster boats should always have hydraulic steering.

Hydraulic steering does not give much feedback to the driver so it should not cause the driver to change direction as a result of torque steer generated by the motor's prop turning. Some of the mechanical steering systems suffer from torque steer. Torque steer can be dangerous.

Dyna-Ski Boats with two motors usually have the same steering motor cylinder that single engine boats do plus a tie bar to connect the steering of the two motors.  Three motored Dyna-Ski Boats should have two motor cylinders and two motor tie bars along with a higher capacity helm to move more fluid.  Needless to say if one cylinder works with two motors it is very safe for a single motor.

Adjustable Tilt Hydraulic Steering

Hydraulic Cylinder is attached under the motor
The two hoses carry the hydraulic fluid to/from the helm

Tracking Fins

 Composite Tracking Fin on a Dyna-Ski Boat

Dyna-Ski Boats have a tracking fin.  Normally tournament style water ski boats have a tracking fin. Fish & Ski, Inboard/Outboards, Runabouts, Pontoon, Deck boats, etc. typically don't.

A tracking fin is designed to help the boat maintain a straight line while being pulled from side to side by water skiers and also help the boat turn at higher speeds.

A person with a boat that has a tracking fin should give some consideration to the tracking fin when loading the boat, beaching the boat on shore and putting the boat on a boat lift.  The tracking fin is not long enough to be a problem during normal operation as the lower housing of the motor and propeller are deeper in the water than the tracking fin.  The trailers we sell with Dyna-Ski boats are built with the tracking fin in mind.

Hydrodyne Boats had a cast metal tracking fin on them. Cast metal is old school. We prefer a fin that should break off instead of tear a hole in the bottom of the boat. While a replacement fin isn't cheap it is way cheaper that fixing a hole in the boat bottom.  Below are pictures of an original never been used cast metal tracking fin and a composite fin that we make in the boat shop.  The cast metal one is not for sale.

Friday, March 9, 2012

Things to consider when buying a Dyna-Ski Boat or others

Dyna-Ski Boats really builds boats to order.  It helps keep our costs down a lot.  It saves the buyers money but it means you do have to plan ahead or risk disappointment.

The more different models and options a manufacturer offers the harder it is to try and stock finished products.  Guessing what the buyers want is a real crap shoot.

We used to be able to order fiberglass materials this week, get it delivered next week and the bill would arrive in the mail at the end of the month or billing cycle.  Not any more.  Now we order material this week and sometimes it does not come for 2 or 3 months. Often times now we have to pay for it when we order it or before they will start our order.  Fiberglass materials have a short shelf life so you cannot simply keep more on hand.  Kind of like food in the refrigerator. Storage space is also an issue not to mention holding costs.

Lead time from trailer companies can be 8 weeks in season.  As I'm writing this March 9th, 2012 it is 4 weeks for trailers.  Teleflex (steering) is usually 3 or 4 weeks year round. The hydraulic division is located in Canada so that adds to the time frame.

Companies also have plant shut downs when it gets slow. This adds to the time frame as many of them build stuff only when it is ordered, paid for and they are in production.

Some sales people go on vacation so that can add a week to the ordering and purchasing process.

The US outboard engine companies are pretty good about shipping product.  However even they have supplier problems from time to time and problems at the model year change over which is July first.  Sometimes a particular size of outboard engine may not be available in June.  Occasionally they run out even in May.

Every time that you think you have seen or experienced it all something new comes into play to mess things up.

A new boat is a big expense.  Trying a boat similar to what you want to buy is a very good idea. Nothing worse than having an expensive item that you don't use or like.

At Dyna-Ski Boats with a prior agreement to a visit to test a Dyna-Ski Boat we will reimburse up to $500 in expenses if you purchase a Dyna-Ski Boat from us within one year of the test drive and/or ski. I'm wanting to get a couple places in warmer areas so we can offer this option year round.  My wife and family (mostly the dog really) would not be happy if I relocated to Florida for the winter so I could offer this option myself from Florida.

Sunday, March 4, 2012

Interesting 17.6 Open Bow uses & pictures

It occurred to me the other day that people may not realize that a Dyna-Ski 17.6 Open Bow can be used for things other than the usual types of water skiing.  We have a para sail and we have used it behind my 17.6 Hydrodyne although I never have taken any pictures.  An owner of Dyna-Ski 17.6 Open Bow sent me the pictures below. In addition to use as a personal ski boat he uses it as a ski team tow boat.

Saturday, March 3, 2012

17.6 Open Bow performance with a 115

115 E-Tec Motor Testing
This was the same boat used for testing the 90 hp E-Tec Motor.

The 115 hp Evinrude E-Tec is a 4 cylinder two stroke motor weighing 369 lbs. This motor is pretty quiet and seems to be very fuel efficient.  I had the motor installed with a pair of transom shims to give the driver more usable trim range. The transom shims give the driver additional control allowing fine tuning of the boat and motor combination on the water. The boat wake size increases and decreases by trimming the motor.  The boat speed also changes when the trim is moved up and down.  The gauges in the dash included a Livorsi GPS Speedometer.  The 115 motor is not as tall as the 90 hp motor. This motor weighs 49 lbs more than the 90 hp E-Tec Motor.

The Evinrude motor is very smooth and fairly quiet, very quiet at idle.  I ran a variety of speeds with several props and the motor held them well.  It was hard to get the boat above 44 mph on the GPS no matter what prop was on the boat.  I tried a whole bunch of them and it would appear that the 115 does not have enough horsepower to turn the taller props at the RPMs to get higher top speeds.  The wake was small at all speeds with the light weight motor.  Remember I'm used to having a 150 on the 17.6 models.  A 150 weighs 418 lbs. which is 49 lbs more than the 115 hp E-Tec Motor.

The prop was a three blade aluminum 17 pitch. The combination had good acceleration and speed holding.  My 7 year old was along for the initial speed testing.  The speeds did not change much even with a six people in the boat.

Speeds were   
14 MPH @ 2500 RPMs
21 MPH @ 3000 RPMs
36 MPH  @ 4700 RPMs   (trimmed for the best slalom wake)
40 MPH @ 5400 RPMs  (trimmed down to improve the barefoot wake)
44 MPH @ 5600 RPMs  (trimmed way up for maximum speed)

The boat and motor combination was very good for all types of skiing.  Speed holding was very solid with good acceleration pulling a single water skier up from deep water.  The barefoot skiing pictures were taken with four people in the boat, three adults and one child.  The ropes were 75’ in length.  Pulling the two barefoot skiers out of deep water with one skier on a flip turn ski and the other on a slalom ski along with the four people in the boat was pretty slow but it did pull them up!  The back barefooter weighed 165 lbs. and the other footer weighed 215 lbs.  The two footers were skiing at 40 to 42 mph together. They each did some one foot barefooting going forward and backwards.  They did not do any one foot while skiing together.  I pulled both footers deep water several times but not at the same time. The boat and motor combination was very easy to drive pulling the skiers no matter what they did.

I'd like to test a 17 pitch stainless steel prop but I did not have one available at the time.

17.6 Open Bow with a 90 E-Tec

Over the years I have gotten a fair number of inquiries from people living on lakes with horsepower restrictions.  About four years ago I borrowed a new Evinrude 90 E-Tec from a local dealer for testing on the Dyna-Ski 17.6 Open Bow that I had at my house. Nothing special was done to the boat or motor for this test. 28 gallon gas tank was full.

90 E-Tec Motor Testing

The 90 hp Evinrude E-Tec is a 3 cylinder 2 stroke motor weighing 320 lbs. This motor is pretty quiet and seems to be very fuel efficient.  I had the motor installed with a pair of transom shims to give the driver more usable trim range.  The gauges in the dash included a Livorsi GPS Speedometer.

The first prop was a three blade stainless steel Viper 13 7/8" by 15".  
I was only able to hit 4500 rpms which was 42 mph on the GPS.  This motor should be running 4500 to 5500 according to the folks from BRP so we were on the low end of the range and slow out of the hole.  I did not further test this prop as it was not suitable for water skiing.  With a little custom work it might be a good riding around prop perhaps?

The testing was being hampered by not being able to trim the motor up while moving from the driver position.  Down worked fine I just could not trim up once it was trimmed down from the driver seat.  It is hard to believe that outboards in the past did not have power trim and tilt.  Now we expect it on every motor.

Second prop was a three blade 13 7/8 by 11". 
I took this prop off of my pontoon boat.  24 MPH at 5500 rpms.  Great acceleration and very steady speed holding. The wife skied on her swivel ski which requires a solid and steady 16 or 17 mph.  4200 rpms was the perfect speed for her.   I pulled my 7 year old son John in a tube by himself (and with mom) and he also knee boarded.  Excellent for holding slow speeds no matter how slow he wanted to go.  Also cruised around with three adults and John in the boat.  Descent performance it just needs more top end.  It took what seemed like a long time to run across 2400+ acre Lake Noquebay vs having a 150 on the back which is what I am used to but the gas gauge on the 28 gallon tank has still barely moved with the 90 out back.

I pulled the boat out of the lake and fixed the motor trim problem.  It took me a long time to find the pinched (and shorted) trim wire in the wiring harness under the motor cowl.  The motor was installed by a local Evinrude dealer.

While the boat was on the trailer I put on a 3 blade Stainless Steel 13 3/4" by 13" SSP Prop.  
Getting 5500 rpms was no problem.  Little if any trim was needed.  Motor had more RPMs available.  Speed was 34 mph on the GPS at 5500 rpms.  Acceleration was descent.  Speed holding was excellent.

Next was a 4 blade Stainless Steel  13 1/2" by 13 Rogue Prop
Getting 5500 rpms took some trim.  Speed was 34 mph on the GPS.  Acceleration was slightly less than the 3 blade. Speed holding was also excellent.

Last was the 3 blade aluminum 13 1/2" by 15" standard prop. 
Getting 5500 took a fair amount of trim.  Speed was 36 MPH on the GPS.  Acceleration was slower than the two props above but better than the Stainless Steel 13 7/8" by 15" Viper.  Speed holding was still real good.

Next is the serious water ski testing.  I borrowed a skier from the local water ski team (185 lbs male).  He was the biggest kid there.  My wife and son were in the boat with me.  225 lbs., 120 lbs. and 45 lbs.  Gas tank was on 3/4 or slightly above.  The new E-Tec 90 hp. motor now has 3 or 4 hours on it.  I pulled the guy up deep water several times on a single wood water ski using a 85’ line attached to the standard ski pylon.  It was a descent pull.  I would not call it slow or fast.  Remember the boat runs 36 mph on the GPS at 5500 rpm without a skier.

I was able to trim up to get 5500 rpm and 36 mph on the GPS Speedometer with the skier behind the boat. He was footing at 35 mph so we lost one mph with him footing.  He said the water was solid and the pull out fine.

I wish that I would have had more time to fine tune the motor and prop combination a little.  Perhaps a 3 blade Stainless Steel 13 3/4" by 14" prop would be better as the 13 3/4" by 13" had better acceleration but would only do 34 mph on the GPS at 5500 rpms. 

In summary the Open Bow 17.6 with a 90 hp motor surprised and impressed me with how well the small motor performed on the water ski boat!  If a person is limited by lake rules or is on a real tight budget a 17.6 Open Bow with a 90 horsepower engine would make for a descent water ski boat.  Some common sense is required though with a low horsepower water ski boat.  You won’t be able to load the boat down with people and barefoot.  If a person is willing to have a few different props and change them depending upon how they using the boat at the time the combination is even better. The nose of the boat stayed down with all motor and prop combinations.

Friday, March 2, 2012

What is going on in the water ski boat world.

With the ever raising price of gasoline (gas was $1.86 a gallon when President Obama took office) it seems like skiers buying new Dyna-Ski boats are planning for the future as 17.6 Open Bow sales are way up this year.  We are even building a 17.6 Open Bow with a two stroke three cylinder 75 hp Evinrude E-Tec engine for a customer.  The Dyna-Ski will be on a lake that only allows up to 75 hp. motors. The engineers at Evinrude say that it will perform very close to the 90 hp Evinrude E-Tec engine that I tested a couple summers ago. I'll have pictures and testing info on this unique boat come summer.  We are going to lighten up the boat slightly and install a smaller gas tank to improve performance of the combination. A small custom boat manufacturing company like Dyna-Ski is able to do this fairly easily.

Smaller engines use less fuel and oil. The only exception is if the motor is having to run to hard or the load is to high to do the task at hand.  With boats sometimes going to a smaller diameter or lesser pitch propeller will increase the RPM's of the motor but also increase the fuel economy as the motor runs in a more powerful and fuel efficient range. As long as you are not over-reving the motor and can get the top speed that you need you will be fine and usually get the best acceleration also. Modern outboards like to operate in the 2000 to 4000 rpm range for best fuel economy as long as the motor is not lugging along.

Water ski boats motors need torque more than top end power. With outboard powered boats it is pretty easy to change the motor on the boat.  Dealers are always happy to get customers that want to repower their boats.

My lake neighbor bought an outboard water ski boat that isn't a Dyna-Ski.  He had bought the boat without realizing that I owned Dyna-Ski Boats and would have made him an awesome deal!  After a couple years he told me he needed a bigger engine as the 115 was not powerful enough for their water ski needs. I told him he should try a different prop first.  I looked at the prop on his boat and gave him two other ones to try.  He bought one of the props from me as it saved him from buying a new larger motor.  I may have screwed up as I could have sold him the new motor most likely, oh well . . . . . . . I'll sell him a new Dyna-Ski eventually.