How do you recommend installing foot straps on the hull of my 1994 SC 17?
I am very familiar with installing them in sailboards ( Divinycell/Epoxy sandwich over EPS core), but that method would not seem to work on a thin walled hollow structure like the Foam sandwich SC hull. Traditional methods of gaining access thru an inspection plate and thru bolting do not seem possible or desirable given the curved surface of the deck.
While I am sure I can come up with a way of inserting some type of backing plate, I would rather not reinvent the wheel if the factory already has put in place back up plates, and can give the locations of them …
Thank You,
Bob
Foot straps...How do you recomend they be installed on SC?
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Tom Haberman
- Expert
- Posts: 48
- Joined: November 15th, 2003, 9:55 am
- Location: Minnesota
- Contact:
Bob,
There is no backup metal for foot straps in any SUPERCAT hull.
In the ARC product line we have added metal to hulls as they are being built ( if client requests them) and have also added metal to older hulls with either of the methods decsribed below.
Normally the foot straps will be located in the non-skid area.
1) Backup metal should be 1/8" thick x 1" wide aluminum
2) Locate straps and mark hull.
3) We use a metal that is the length of the installed strap. This long piece will give a large bonding area and assure ultiimate strength.
4) Remove all non-skid and gel coat down to bare glass laminate.
5) Prep the aluminum by sanding with 40 grit , rough surface is critical for good bond.
6) Using epoxy/cabosil mix bond the metal into place. Let cure fully.
7) After metal is secure you should sand out about 1.5" all around the metal , remove paint & gel coat down to bare glass.
Cut glass patches ( we use 4oz or 6oz glass cloth. total of approximately 20 oz.) Cut the patches on the bias so that all glass strands will cross over the metal.
Each patch should be a bit larger than the previous to help taper the patch better. Patch should go out onto hull about 1.5" past the installed metal.
9) Install the patches over the metal, smallest first, largest last.
10) After all patches are installed you can add some fairing putty over the entire area. Epoxy with micro balloons works great.
11) After your patches and putty has cured you can smooth out the area and apply non-skid paint.
12) Install your foot strap and away you go.
A second method requires more work but is stronger and you will not have the raised area under the strap.
The steps are similar but the metal is actully recessed down into the foam core. ( Caution must be used with this method to make sure that you are actually mounting the metal in area that has foam core )
The hull laminate is removed and just enough core is removed too to place the metal below the outer surface of the hull. Installation of the metal is the same as the first but three additional layers of glass are required.
Installing backup metal will require some skill and time but installing foot straps without backup metal is not recommended.
Good luck with your foot strap installation.
Tom
There is no backup metal for foot straps in any SUPERCAT hull.
In the ARC product line we have added metal to hulls as they are being built ( if client requests them) and have also added metal to older hulls with either of the methods decsribed below.
Normally the foot straps will be located in the non-skid area.
1) Backup metal should be 1/8" thick x 1" wide aluminum
2) Locate straps and mark hull.
3) We use a metal that is the length of the installed strap. This long piece will give a large bonding area and assure ultiimate strength.
4) Remove all non-skid and gel coat down to bare glass laminate.
5) Prep the aluminum by sanding with 40 grit , rough surface is critical for good bond.
6) Using epoxy/cabosil mix bond the metal into place. Let cure fully.
7) After metal is secure you should sand out about 1.5" all around the metal , remove paint & gel coat down to bare glass.
Cut glass patches ( we use 4oz or 6oz glass cloth. total of approximately 20 oz.) Cut the patches on the bias so that all glass strands will cross over the metal.Each patch should be a bit larger than the previous to help taper the patch better. Patch should go out onto hull about 1.5" past the installed metal.
9) Install the patches over the metal, smallest first, largest last.
10) After all patches are installed you can add some fairing putty over the entire area. Epoxy with micro balloons works great.
11) After your patches and putty has cured you can smooth out the area and apply non-skid paint.
12) Install your foot strap and away you go.
A second method requires more work but is stronger and you will not have the raised area under the strap.
The steps are similar but the metal is actully recessed down into the foam core. ( Caution must be used with this method to make sure that you are actually mounting the metal in area that has foam core )
The hull laminate is removed and just enough core is removed too to place the metal below the outer surface of the hull. Installation of the metal is the same as the first but three additional layers of glass are required.
Installing backup metal will require some skill and time but installing foot straps without backup metal is not recommended.
Good luck with your foot strap installation.
Tom
Sincerely,
Tom Haberman
Tom Haberman
Thank you Tom for such a complete explanation. I appreciate you taking the time to share this with me...
I had one other thought that I would like to run by you...
Is there any wax in the last coat of resin on the inside of the hulls? What would be your opinion of this method...
Drill one 13/16"" hole completely thru the deck, centered between where the foot strap machine screws would be (fore and aft). Take a piece of aluminum plate prepped like you suggested but have it 3/4"wide and it long enough to go 2" past each foot strap hole (aprox 10" long). Drill a small hole in the center of the 1/8 X3/4"X 10" aluminum plate and insert a piece of 300+ pound test mono to use to pull the plate tight against the inside surface of the deck. Load the top of the plate with 3M 5200 and insert in hole...pull plate tight against deck and allow to cure. Drill out foot strap installation holes and take a small allen wrench to dig out the foam around the hole and fill with cabosil or hammer mill and epoxy (fill the 13/16" center hole as well at this time with small pieces of cloth and epoxy)... If carefully done with surrounding area masked off and a thin piece of plastic stretched tightly over the repairs, little if any sanding would be required...Drill out and tap aluminum plate to accept 10X24 SS machine screws...install straps with SS fender washers while bedding with 3M 101.
My method is still a lot of work but, other than the center hole to put the aluminum plate into the hull, everything done would be hidden by the foot strap once installed, no raised area and minimum painting and non skid touch up...What do you think? Would it fly?
Could I get a good enough bond to the inside of the hull?
Your opinion is greatly appreciated...
Bob
I had one other thought that I would like to run by you...
Is there any wax in the last coat of resin on the inside of the hulls? What would be your opinion of this method...
Drill one 13/16"" hole completely thru the deck, centered between where the foot strap machine screws would be (fore and aft). Take a piece of aluminum plate prepped like you suggested but have it 3/4"wide and it long enough to go 2" past each foot strap hole (aprox 10" long). Drill a small hole in the center of the 1/8 X3/4"X 10" aluminum plate and insert a piece of 300+ pound test mono to use to pull the plate tight against the inside surface of the deck. Load the top of the plate with 3M 5200 and insert in hole...pull plate tight against deck and allow to cure. Drill out foot strap installation holes and take a small allen wrench to dig out the foam around the hole and fill with cabosil or hammer mill and epoxy (fill the 13/16" center hole as well at this time with small pieces of cloth and epoxy)... If carefully done with surrounding area masked off and a thin piece of plastic stretched tightly over the repairs, little if any sanding would be required...Drill out and tap aluminum plate to accept 10X24 SS machine screws...install straps with SS fender washers while bedding with 3M 101.
My method is still a lot of work but, other than the center hole to put the aluminum plate into the hull, everything done would be hidden by the foot strap once installed, no raised area and minimum painting and non skid touch up...What do you think? Would it fly?
Could I get a good enough bond to the inside of the hull?
Your opinion is greatly appreciated...
Bob
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Bill Roberts
- Expert
- Posts: 515
- Joined: November 17th, 2003, 9:13 pm
- Location: Stuart, Florida
Foot Straps
Hi Bob.
There are two locations where you can install foot straps with no problems. One is on the rudderhead and the other is on the end, end cap of the rear beam.
Good Sailing,
Bill
There are two locations where you can install foot straps with no problems. One is on the rudderhead and the other is on the end, end cap of the rear beam.
Good Sailing,
Bill
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Tom Haberman
- Expert
- Posts: 48
- Joined: November 15th, 2003, 9:55 am
- Location: Minnesota
- Contact:
Bob,
Your method is good but limits where you can place the straps. You have to have a clear unobstructed surface on the inside and normally it will be close to the beam and there are bulkheads in that area.
We also usually mount them at an angle and it is easier to form the metal on the outside of the hull.
As long as you have a good clear area inside the hull your method will be a good secure mount.
Tom
Your method is good but limits where you can place the straps. You have to have a clear unobstructed surface on the inside and normally it will be close to the beam and there are bulkheads in that area.
We also usually mount them at an angle and it is easier to form the metal on the outside of the hull.
As long as you have a good clear area inside the hull your method will be a good secure mount.
Tom
Sincerely,
Tom Haberman
Tom Haberman
Thank you to Bill and Tom…it is such a pleasure to be able to ask questions and get an informed expert opinions.
Bill…I wish I would have asked you about the foot straps when I was down looking at your new ARC 17. I would have been so much easier to understand exactly what you mean when you say “on the rudder head” or “on the end cap”. I am use to putting foot straps on sailboards with fasteners about 6-1/2” center to center (fore and aft) since the end cap is not that large in diameter, I am having a little difficulty envisioning it…and the rudder head? Where exactly? Doesn’t seem like it would be too comfortable…I am not quite sure I understand the exact positions you are speaking of…
Tom…thank you for such a complete answer. If I would have tried my proposed method next to a bulkhead (very likely in that area) I might have drilled a hole in my deck for nothing. I am glade I waited for your reply before proceeding…
Many thanks to both of you…
Bob
Bill…I wish I would have asked you about the foot straps when I was down looking at your new ARC 17. I would have been so much easier to understand exactly what you mean when you say “on the rudder head” or “on the end cap”. I am use to putting foot straps on sailboards with fasteners about 6-1/2” center to center (fore and aft) since the end cap is not that large in diameter, I am having a little difficulty envisioning it…and the rudder head? Where exactly? Doesn’t seem like it would be too comfortable…I am not quite sure I understand the exact positions you are speaking of…
Tom…thank you for such a complete answer. If I would have tried my proposed method next to a bulkhead (very likely in that area) I might have drilled a hole in my deck for nothing. I am glade I waited for your reply before proceeding…
Many thanks to both of you…
Bob