HOPKINS HI-PERFORMANCE PROPELLERS
"WE PUT THE PRO IN PROPELLER"
HOPKINS PROPELLER SERVICE LLC. · 70415 CHARLIE STREET COVINGTON, LA 70433 · PHONE: 985-892-3868 FAX: 985-892-3416

 

HOPKINS PROPS SALES REPAIRS

"How To Break In A New Hub"

Hopkins' is considered one of the best dealers in aluminum props, stainless steel propellers because of discount prices and fast service in boat props.

How To Break In A New Hub HOPKINS PROPELLER SERVICE LLC. CHARLIE STREET COVINGTON, LA 70433

Props are as we know very expensive to replace. So please as Glen Hopkins' recommends you should always have a spare!

When dealing with boat  props of any type for any reason, one should always handle them in a careful safe manner. Always using gloves, safety glasses and closed shoes are a must. The sharp edges of the propeller should be kept away from your body. Proper wrenches should be used. The engine must be placed in neutral gear and the ignition key removed, prior to prop removal or installation. Not following these tips can often cause serious bodily harm. And as we know prop failure can happen at any point and time with no warning.

 I always personally recommend to my many customers that they should always carry a spare prop, hardware, and tools, in the boat and know how to successfully replace a failed prop. And over the years many have personally thanked me for this advice first hand. Persons not capable of these operations should avoid these situations that will potential to put himself or herself or anyone else in harm's way. And be sure to carry on board communication devices to alert the Coast Guard of their troubles.

Many problems often start by persons dropping and dinging blades before they are even put into use.

Your propeller should be inspected annually as well as every 100 operating hours and after every impact strike. Any damage should result in a proper immediate repair or replacement.

As many  are not aware of propellers are subject to great stresses if a mechanical flaw exists (or develops) in the propeller, it is may I stress here imperative that  you as the operator of the boat is utilizing the prop according to these guidelines, so as to avoid the risk of injury to the operator, passengers, or others.

Boats and Propellers should be operated with the knowledge that, as most mechanical devices, they are subject to failure. Cautions should always be taken to ensure that in the event of  a prop failure, all human life is protected. The number one rule I always stress is "AVOID" at all cost  "LOCATING OR SITTING  PERSONS IMMEDIATELY ABOVE THE PROP! No one should ever be located above an operating prop. Propellers do lose blades and disintegrate often sending flying shards in every direction..

Avoid operating your prop in mud, sand, surface penetrating operation, or any entanglements, which might prematurely stress the propeller. Unless the prop is designed for such. If forced to operate a normal prop in such a condition, extreme care is required as the prop is subject to serious failure and damage. Such a condition exposes nearby persons to possible lethal hazards.

Take care that before starting the propeller rotation on any vessels of with any size to inspect the conditions around the motor and propeller areas, the captain is responsible to inspection of this prior to starting the propeller rotation.  When you remove and/or properly set propeller as a spare in you boat where it cannot roll around or fall during transport or storage be sure to place it blades facing down.

Most propellers have a splined bushing in the hub that attaches the propeller to the propeller shaft. The bushing is mounted to the propeller with flexible rubber. This rubber acts like a shock absorber. If the propeller strikes something hard, the rubber flexes and helps protect the gearcase components from damage.

To know you have a hub slippage problem begining a boat owner will notice increased engine RPM and slower forward boat movement.

Sometimes the hub will slip inside of the propeller at higher rpm's. ... slips, you should be able to smell burning rubber at the rear of the boat. And this is the first sure obvious sign you need a full hub replacement right away.

The quickest way to check a bad hub is to try another propeller to see if it slips at the same rpm's or you can try putting a dab of paint on the hub and a dab on the prop and try it to see if the 2 marks still lineup after a trial run. If the hub has spun, you will have to take it to a prop shop for a hub replacement.

Please note: Inspecting each year and careful expert reworking of the blades can reduce prop slip.

Hub Replacement is necessary when replacing spun hubs, care should be taken to prevent injury, as a great deal of pressure is necessary to perform this operation. Equipment Required A hydraulic press rated at ten (10) tons or better. The proper installation funnels, drivers and propeller supports.

Through the years hubs and propellers have been modified by the manufacturers. Changes such as decreasing the outside diameter of the hub bore to allow for better exhaust and manufacturing the hubs using a harder rubber to prevent slippage. A hub is not a slip clutch. Its only purpose is to absorb shock to the drive train when shifting.

If the propeller appears to be OK and your still having the same problem, it could be the coupler at the back of the engine. Generally speaking, if the rubber hub inside of the engine coupler slips, you should be able to smell burning rubber at the rear of the boat. If the boat is in the water and you have someone with you, you can have them look behind the engine to see if the driveshaft coming out of the coupler going to the outdrive has the same rpm when the slippage occurs. If the engine rpm increase but they see the driveshaft rpm decrease, the coupler is bad. Sometimes the engine will even start to overheat because the water pump in the outdrive is not turning fast enough to cool the engine.

How To Break In A New Hub

How To Break In A New Hub

The Hub Solid cylinder is located at the center of the propeller to which each prop blade is attached. Hub shapes include cylindrical, conical, radius & barreled, with the center of the Hub Bored to accommodate the engine propeller shaft. A hub repair replacement is when the failed rubber bushing in an outboard's propeller slips or becomes damaged.

 

How To Break In Your New Hub

How To Break In A New Hub

Idle for the first 5-10 minutes. Shift alternately between forward and reverse. This washes away lubricant left from instillation and allows the new hub to seat. Avoid "Jack Rabbit" starts from the first couple of hours of use.

HOPKINS PROPELLER SERVICE LLC. CHARLIE STREET COVINGTON, LA 70433 PHONE: 985-892-3868 FAX: 985-892-3416

 

A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid (such as air or water) is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's principle and Newton's third law. A propeller is often colloquially known as a screw.

A boat propeller transmits power by converting rotational motion into thrust. Usually consisting of 3 or more blades, a boat prop spins around a central shaft to create dynamics similar to a rotating screw or airfoil. When blades spin, a pressure difference between the forward and rear surfaces is produced, accelerated the water behind the blade to create force.

In larger and more modern engines, a rubber bushing transmits the torque of the drive shaft to the propeller's hub. Under a damaging load the friction of the bushing in the hub is overcome and the rotating propeller slips on the shaft preventing overloading of the engine's components. After such an event the rubber bushing itself may be damaged. If so, it may continue to transmit reduced power at low revolutions but may provide no power, due to reduced friction, at high revolutions. Also the rubber bushing may perish over time leading to its failure under loads below its designed failure load. Whether a rubber bushing can be replaced or repaired depends upon the propeller; some cannot. Some can but need special equipment to insert the oversized bushing for an interference fit.

In some modern propellers, a hard polymer insert called a drive sleeve replaces the rubber bushing. The splined or other non-circular cross section of the sleeve inserted between the shaft and propeller hub transmits the engine torque to the propeller, rather than friction. The polymer is weaker than the components of the propeller and engine so it fails before they do when the propeller is overloaded.

Notes

  1. ^ Mario Theriault, Great Maritime Inventions Goose Lane Publishing (2001) p. 58-59
  2. ^ "Patch's Propeller", Scientific America, Vol. 4, No. 5 (October 10, 1848) p. 33, featured in The Archimedes Screw website retrieved 31 January 2010
  3. ^ "History and Design of Propellers: Part 1". the boatbuilding.community. 2004-02-07. Retrieved 2007-09-03. "Francis Petit Smith accidentally discovered the advantages of a "shortened" Archimedean screw. Originally, his wooden propeller design had two complete turns (what we might call "double-pitch"). Nevertheless, following an accident in a canal, his boat immediately gained speed after half of his blade broke away."
  4. ^ Illustrations of skewback propellers
  5. ^ http://www.engineeringnews.co.za/article/a-new-start-for-marine-propellers-2005-03-18
  6. ^ Getchell, David, The Outboard Boater's Handbook
  7. ^ Admiralty Manual of Seamanship
  8. ^ US 5484264, Karls, Michael & Daniel Lindgren, "Torsionally twisting propeller drive sleeve and adapter", published March 8, 1994, issued January 16, 1996

Propellers

  1. Be handled carefully, using heavy gloves, body covering protection, safety glasses and safety shoes. The sharp edges of the propeller should be kept away from your body. The prop should not be stored in such a fashion that it could drop or fall upon a person. Proper wrenches and prop removal blocks are required. The engine must be placed in neutral gear and the ignition key removed, prior to prop removal or installation.


  2. Be removed and/or properly covered (with durable safety covers) during boat or propeller transport or storage.


  3. Be used with great caution. You should always be at idle speed and minimal rpm's whenever you are near other boats, docks, or persons.


  4. Not be used if the operator or passengers are under the influence of drugs or alcohol.


  5. Only be used by an alert, rested, properly trained operator.


  6. Be inspected annually and every 100 operating hours and after every impact strike. Any damage should result in a proper repair or replacement. Propellers are subject to great stresses (as well as cavitation and impact damage) and their mechanical capabilities deteriorate over time. Additionally, if a mechanical flaw exists (or develops) in the propeller, it is imperative that the operator is utilizing the prop according to these guidelines, so as to avoid the risk of injury to the operator, passengers, or others. AVOID LOCATING PERSONS IMMEDIATELY ABOVE THE PROP! No one should ever be located above an operating prop unless the craft is equipped with a shatter shield. Propellers do lose blades and disintegrate. No one should ever be allowed in the potential arc travel of a disintegrating propeller.


  7. Be operated with the knowledge that, as most mechanical devices, they are subject to failure. Care should be taken to ensure that, in the event of failure, all human life is protected. Examples might be to avoid; cutting in front of larger craft, operating in close proximity to a dam or spillway, operating a craft in floods or severe storms, operating out of range of communications with rescue agencies, operating the prop near the surface of the water (exposing bystanders to danger in the event the propeller disintegrates), and racing.


  8. Be supported by a backup prop, hardware, tools, and knowledge to successfully replace a failed prop. Persons not capable of these operations should avoid situations with the potential to put themselves in harm's way.


  9. Avoid operating the prop in mud, sand, surface penetrating operation, or any entanglements, which might prematurely stress the propeller. If forced to operate in such a condition, extreme care is required as the prop is subject to catastrophic failure and disintegration. Such a condition exposes nearby persons to extreme hazards.


  10. Be used in an area devoid of loose ropes, loose clothing, fishing lines, nets, etc. which might become entangled in the prop. This poses a potential hazard to those nearby, who might be harmed by being pulled into the propeller (or water, or other deck hazards).


  11. Be operated by persons over the age of 16, who are appropriately trained for the size of craft being operated. An adult should supervise operators under the age of 18. Some areas may have specific age laws, which should be specifically followed.


  12. Be used only on motors properly equipped with anti-kickback devices, preventing the engine from breaking loose from its normal transom position and flipping over into the boat.


  13. Be used only on motors equipped with operator kill switch protection, preventing the continued operation of the craft if the operator is ejected. Approved flotation devices must always be worn. Follow all Coast Guard regulations.


  14. Be cleared of all persons or objects prior to engagement. Take care that on vessels of such size that the operator cannot physically verify (while located at the operator's console) the "safe to start propeller" condition, that a responsible person attends this inspection prior to authorizing the engagement of the propeller rotation.


  15. Be operated with passengers safely located. Special care must be taken to avoid operations with persons sitting, standing, or otherwise located near the front of the boat, in anything other than a totally secure position. This is extraordinarily hazardous in that a man overboard may be run over by the boat and prop. Always secure all persons behind guards of sufficient height to safely retain them in the vessel.


  16. Be utilized at a legal speed safe for the operating conditions. Almost all craft are capable of speeds in excess of safe operating conditions. Use good judgment. Just because you can go fast doesn't mean it is safe or legal!


  17. Be utilized allowing adequate distance between any boat you are following. Do not allow other boats to follow your craft too closely. Allow a margin of time for recognition of a developing hazard and sufficient distance to come to a stop. Do not operate at speeds which would, in the event of a loss of control, allow you to impact other boats, marine facilities, or bystanders. Since most marine vehicles do not possess braking devices, safe operation distances for collision avoidance must include adequate distance to "coast to a stop".


  18. Be used when visibility is good. Avoid operations in poor visibility or night, without adequate navigational equipment.


  19. Propeller guards may be available from aftermarket sources for your application, particularly if low speeds or rescue craft are involved. If you would like assistance, please contact our engineering staff. We also design propellers to help partially reduce some of the negative performance characteristics of propeller guards or shrouds.




Hazards Relating to Propeller Materials

Propellers are made from a variety of materials including brass, bronze, stainless steel, aluminum, and plastics. The are typically packaged with rubber accessory members and paper/plastic packaging. Various glues or additives may also be used. In ordinary use for the purpose of a propeller, it poses no chemical danger to its operator or installer. However, some of the materials involved, may be cancerous or cause reproductive system toxicity, or present other health hazards, if ingested in quantities exceeding the recommended maximum levels. Avoid ingesting propellers, propeller material by-products, or their related packaging and accessories. Recycle or dispose of unused propellers (and their associated by-products) responsibly, in an approved recycling facility or landfill. MSDS available upon request.

© 2012 PowerTech! Propellers - Official Website All Rights Reserved USED WITH PERMISSION

HOPKINS PROPELLER SERVICE LLC. CHARLIE STREET COVINGTON, LA 70433


HOPKINS PROPELLER SERVICE LLC. CHARLIE STREET COVINGTON, LA 70433

PHONE: 985-892-3868 FAX: 985-892-3416

  • Propeller Repair & ConditioningShaft Repair & StraighteningStrut & Rudder RepairBearing ReplacementHub Replacement
  • Pitch Change
Hopkins' always recommends Safety first and a Big Part is keeping your equipment in good working order.