From: heon@cbnewsg.cb.att.com (garry.j.heon)
Subject: Boat lift, HELP
Keywords: Need help!!!!!
Organization: AT&T
Date: Mon, 31 Aug 1992 18:58:41 GMT

I'm now in the market for a new boat lift.  I'm looking for
a 4 post cradle lift.  I thought it would be an easy decision
but I found two companies with conflicting claims.  I don't
know which would be better, aluminum or galvanized steel.
Anyway here's a copy of a "Fact Sheet" and responses to
the "facts" from a competitor.  Who do I believe?
Price between the two is almost nothing.
ANY HELP WOULD BE GREATLY APPRECIATED!!!!!!!

Re-printed without the permission of either company.

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                        Davit Master "Fact Sheet"
                                   and
                             Hi-Tide Response


       While there are many boat lift manufacturers, and it is not
       Hi-Tide Sales' policy to criticize anyone; the
       misstatements, misrepresentations, slander, and play on
       words contained within the Davit Master Fact Sheet induce
       our response.  There are many aluminum boat lift
       manufacturers, and statements concerning marine grade
       aluminum apply to all.  We hope that being better informed
       will guide you to select a lift that lives up to the
       expectations for which you but it, whether galvanized steel
       or aluminum, regardless of the manufacturer.  We have re-
       printed Davit Master's "Facts" below with our response
       immediately following.

                         Davit Master Fact Sheet

       Comparisons between aluminum claims against galvanized steel
       and other considerations.

       Davit Master

       1.  Corrosion_protection:

       The integrity of steel construction is maintained throughout
       the manufacturing process then when the fabricated part is
       complete it is hot dipped galvanized as a whole unit.
       Aluminum boat lifts offer no significant advantage in
       corrosion protection.  Aluminum by itself does oxidize
       without any significant detriment but when combined with
       dissimilar metals such as stainless steel, the corrosion is
       accelerated greatly with serious results.  Bolts and pins
       may become fused into the aluminum and under some conditions
       the aluminum may actually dissolve.

       Hi-Tide Sales, Inc.

       Aluminum and stainless steel are compatible and have been
       used together for many years.  A quick look around your boat
       will support this fact.  Anything dissolving?  Aluminum boat
       lifts offer very significant advantages in corrosion
       protection:

         1.  Lifts in service for 10 years show insignificant
             oxidation while a galvanized steel boat lift will have
             rusted away.

         2.  Due to the stainless steel components, fasteners will
             be functional for service long after galvanized
             fasteners have seized together with rust.

       Davit Master

       2.  Integrity_of_galvanized_steel

       It has been claimed that galvanized steel is steel which has
       been zinc coated and the coating can be removed by scraping,
       shipping or usage damage or exposure to salt water
       environment.  This is false.  The hot dipped galvanizing
       process uses 850 deg. heat which creates a metallurgic bond
       between zinc and steel where the zinc becomes part of the
       steel it protects.  These metals react chemically resulting
       in four layers of zinc and zinc-iron alloys which are
       chemically fused into the base steel.  It is impossible to
       scrape or chip off this surface because of it being an
       integral part of the base metal.

       Hi-Tide Sales, Inc.

       The galvanized coating, will not scrape or chip off under
       normal usage conditions, however, many times the coating
       does not adhere to the steel due to lubricants the steel
       mills use to keep the raw steel from rusting.  Nevertheless,
       the galvanized coating is this.  When slid along of a truck
       or forks of a forklift, as in shipping and installation, the
       thin zinc coating can be penetrated.  Therefore care must be
       exercised to insure coating integrity.

       Davit Master

       3.  How do aluminum and galvanized steel compare to a salt
           water environment?

       Galvanized steel components have been used successfully in
       the marine environment for 122 years (since 1830) while
       aluminum has been used in the boat lift application for only
       5-7 years.  Aluminum has been used as seawalls for many
       years however they are not exposed to the stress created in
       boat lift applications and they are designed so that
       stainless steel and other dissimilar metals never contact
       the aluminum.  Stainless steel is never attached and the
       steel tie-back rods utilize rubber insulation pads between
       the backing plates and the aluminum wall.  Aluminum and
       stainless steel are dissimilar metals and are not
       compatible.  Each by themselves offer good corrosion
       protection but in combination can cause significant
       problems.

       Hi-Tide Sales, Inc.

       Aluminum is used in sea walls for longevity; galvanized
       steel has a short service life with continuous salt water
       exposure.  Marine contractors use stainless steel tie-back
       rods when salt water exposure is a factor, otherwise,
       galvanized steel tie-backs are used.  Marine contractors
       consulted by Hi-Tide use only a backing plate in either case
       without practical problems.  In a technical sense however,
       isolation of galvanized steel and aluminum will prevent
       minimal corrosion that could occur.

       The forces exerted on a sea wall are tremendous, equal to or
       exceeding those of a boat lift!  Sea walls, as well as Hi-
       Tide boat lifts, are designed by licensed engineers.

       Davit Master

       4.  Claim that galvanized steel lifts will only last 5-6
           years while aluminum lifts will last 30-50 years.

       This is a ridiculous claim.  The galvanized coating used on
       steel share many of the same alloy materials that make up
       aluminum and with proper routine maintenance galvanized
       cradles will last a long time.  How long, we don't really
       know; however Davit Master has cradle lifts and marine
       elevators in service for 12 years and they are still
       serviceable (this is fact, not fiction).  Aluminum cradles
       have been in service for 5-6 years (a far cry from 30-50
       years) and have had their problems with stress cracks,
       broken welds, sagging and even floating causing cabling
       problems.  In addition, they still will be subject to
       corrosive problems caused by combining aluminum and the
       stainless steel bolts and pins used in their construction as
       previously discussed.

       Hi-Tide Sales, Inc.

       First, 6061 T-6 marine aluminum contains only 1/4 of 1%
       (0.0025) zinc.  Second, galvanized is defined by Webster's
       Dictionary as "coat iron or steel with zinc."  Therefore,
       galvanize is the term for the process.  The material, zinc,
       is a natural anode in salt water.  Zinc tabs are used on
       drive units and propeller shafts of boats because they will
       erode first, saving the surrounding materials they are in
       place to protect.  New boat owners are often amazed by the
       amount of zinc missing from the tab after only one season.
       When the zinc coating erodes from the boat lift beams, the
       steel is free to rust.  Finally, the other alleged problems
       above are unknown to Hi-Tide.

       Davit Master

       5.  Strength_of_aluminum_versus_galvanized_steel.

       It has been claimed that aluminum is approx. 1/3 the weight
       of steel and that one pound of aluminum is 3 times stronger
       than one pound of steel.  Fact, aluminum is lighter that
       steel however pound for pound it is only as strong as steel,
       however galvanized steel has the bending strength of 3 times
       that of aluminum resulting in a considerable reduction in
       twist, buckling and sagging under load.  But where is the
       advantage if, for example, a load requirement calls for an
       I-beam structure of 8" height at 12lbs. per foot.  Whether
       built from steel or aluminum the structure will still weigh
       12 lbs per foot.  Any aluminum that weighs less than its
       steel counterpart will have a lesser load bearing capacity.
       Further, any welding or significant heating of the aluminum
       alters the tensile strength of that part which reduces the
       strength by almost 1/2 the original strength.

       Put in perspective, would you put your boat on a lift
       constructed of an aluminum beam weighing 3lbs per foot if
       you knew that the appropriate steel boat lift was
       manufactured from beams weighing a required 9lbs per foot?
       Further, welded steel maintains its original tensile
       strength while any welding on aluminum anneals the materials
       causing the strength to be reduced by almost half.  When a
       claim is made that an aluminum cradle is only 1/3 the weight
       of a galvanized steel lift they neglect to tell you that it
       also has half the strength.

       Hi-Tide Sales, Inc.

       Marine aluminum of T-6 temper is approximately 1/3 the
       weight of steel I-beams of the same size and will carry
       approximately the same loads at the same factor of safety.
       Hi-Tide boat lifts are carefully designed and engineered;
       our minimum safety factor is 40% with many of out models
       capable of 100% overload.  These are the highest, safest
       standards in the industry and remain unequaled.

       As an example, a Hi-Tide 11,500 lb capacity galvanized boat
       lift uses an 8" steel I-beam weighing 18.4 pounds per foot.
       Our 12,000 lb capacity Ro-Lift uses an 8" I-beam weighing
       only 7 pounds per foot!  Both have the same factor of
       safety.  If Davit Master's claim were true, the Ro-Lift
       would support only 4,000 pounds.  Being our most popular
       model Ro-Lift, there are thousands in service.

       The high temperature of welding reduces the strength of all
       materials, therefore, proper welding standards, practices,
       and design must be utilized. Likewise the high temperature
       of galvanizing creates some additional weakness that should
       be accounted for in engineering and factor of safety.

       Hi-Tide Sales has never had a weld failure on any of our
       products.  Our aluminum Ro-Lifts are available from 3,000 to
       100,000 pounds.  Yes, 50 tons or the equivalent weight of 35
       automobiles!

       Davit Master

       6.  Integrity_of_chain_drive_systems.

       All Davit Master drive systems are engineered to reduce the
       actual loading at the chain significantly.  A 20 to 1 safety
       factor is always maintained (industry standard is only 5 to
       1) and of the thousands of lifts in service we have never
       had a chain failure.  Chain drives are a moving, working
       assembly and like all mechanical equipment does require
       periodic inspection and maintenance.

       Hi-Tide Sales, Inc.

       Inspection of various chain drive systems will show that
       Hi-Tide uses R60 chain, larger than Davit Master and most
       manufacturers.  Again, the best safety factor.

       Davit Master

       7.  How_long_do_cables_last?

       Regardless of use (or non use) we recommend that cables be
       inspected every time the lift is used and should be checked
       for any fraying or broken strands and replaced every 16 to
       24 months.  Although Davit Master uses high quality
       stainless steel cable, factors such as friction, working and
       bending, oxidation and even the salinity of the water will
       affect the life expectancy of the cable.  Consider that by
       law all commercial lift equipment must have cables replaced
       annually.

       Hi-Tide Sales, Inc.

       While some manufactures use galvanized steel cable that
       rapidly rusts, necessitating frequent replacement, Hi-Tide
       uses stainless steel aircraft cable.  Cable life has many
       variables and should be checked regularly.

       Accelerated cable wear can result from rubbing against
       sheaves or rubbing against itself, causing individual
       strands to break.  Another problem is sheaves binding in
       place due to rust, corrosion or salt accumulation.

       Hi-Tide sheaves are machined with beveled edges, a grease
       retention pocket, and have a stainless steel axle bolt with
       a grease fitting to prevent such problems.  Our cable
       winders guide the cable to prevent it from rubbing against
       itself or sliding on the drive shaft.  Hi-Tide boat lifts
       utilize less of the cable's allowable design load to insure
       longer life and better safety.  Cable replacement is not a
       common occurrence on our boat lifts.

       Davit Master

       8.  Warranty.

       Davit Master offers a one-year warranty on all components
       except cable.  Some aluminum boat lift companies make claims
       of a 10 year warranty.  However when specific questions are
       asked we find that the 10 year warranty only refers to the
       integrity of their manufacture and workmanship and that the
       product is free from structural defects.  They than offer a
       1 year warranty that covers the items which potentially
       could be a problem such as motors, switches and wiring,
       bearings and the lift itself.

       Considering that Davit Master stands behind every product it
       builds and if there ever is a structural defect caused by
       poor workmanship we have take care of it regardless of age
       or ownership of the product, then their warranty is no
       better (in fact if you read all of their disclaimers,
       their's is no as good).

       Hi-Tide Sales, Inc.

       Hi-Tide warrants its lifts for 1 year "bumper to bumper",
       INCLUDING THE CABLES.  Due to the use of aluminum combined
       with the finest engineering in the business, we can and do
       offer a 10 year structural warranty on our Ro-Lift.  This
       includes all carrier and support beams, all welds, and
       bearings.  Will Davit Master replace your rusted out beams
       after 6 to 8 years or even 10 years?  We build aluminum
       replacement beams for galvanized steel boat lifts regularly.

       Davit Master

       9.  Why should you consider aluminum lifts over galvanized
           steel?

       Only if you have allowed yourself to be misled by half-
       truths and twisted facts.  Davit Master introduced cradle
       lift systems to the national market 12 years ago and will
       only use galvanized steel in their construction.  Since
       then, many thousands have been sold and almost all of our
       lifts are still in service and should still be for many
       years to come.

       Much of our knowledge of fabricated aluminum products comes
       form our sister company, Nautical Structures.  They build
       davits, hydraulic cranes, radar arches, boarding stairs and
       other products from aluminum and stainless steel for use on
       the world's finest yachts and is an industry leader in the
       proper use of aluminum in a marine environment.  If aluminum
       really was the best material for boat lifts, Davit Master
       would have been the first to offer it to our valued
       customers.

       A Davit Master lift has always been and will continue to be
       you best boat lift investment.

       Hi-Tide Sales, Inc.

       Interesting that Davit Master's sister company builds
       products of Aluminum and Stainless Steel for the world's
       finest yachts.  If you have a fine yacht, you need a fine
       aluminum and stainless steel Ro-Lift from Hi-Tide since 1979
       (13 yrs.).

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Any data being scientific or not would be greatly appreciated!!!!

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* MY OPINIONS.............AT&T's NETWORK *
*                                        *
* Garry Heon                     AT&T    *
* heon@cbnewsg.att.com       Holmdel, NJ *
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