I guess you really do not want your engine flopping around in the engine bay do you?
I Noticed the engine stringers have gotten soft on my 1978 F26. Who has replaced these and could provide some insight on what needs to be done, and who has done it on this model. Your help is appreciated
f26 engine stringer replacement
Moderators: BeaconMarineBob, Moderator, BeaconMarineDon
No - thats bad - friend of mine had one of his 502's break loose at full throttle (Luhrs 36) and flop around quite a bit - very ugly.
Search the forum - there's been some very good info (including pix) on stringer replacements.
Search the forum - there's been some very good info (including pix) on stringer replacements.
Captain Ross, 2009 Trojan Boater of the Year
"Viva Mahia" F32 Cummins 6BTA diesels,
"Mack Attack" Chaparral 244 Fish, SeaPro 180, McKee 14, Montauk-17
"Viva Mahia" F32 Cummins 6BTA diesels,
"Mack Attack" Chaparral 244 Fish, SeaPro 180, McKee 14, Montauk-17
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Surf and Sand
- Registered user
- Posts: 23
- Joined: Mon Jun 07, 2010 5:52 pm
- Location: Daytona Beach, FL
OK then here we go. The first thing that should be done is to determine how much of the stringer requires replacement. A simple way to do this is to start in a location that you know requires attention, measure a distance along the stringer 12 to 18 inches then drill a prospect hole into the stringer. Use a Ø1/4" drill bit or a little larger. The idea here is to see if the wood under the fiberglass is wet and rotted or good solid wood. Keep doing this along the stringer until you hit solid wood. The floor in the cabin may have to be removed to inspect the stringer if you don't hit good wood before getting this far. Inspection holes in good sections of stringer can be filled with epoxy. Small sections of stringer that are a little soft can also be repaired by injecting them with epoxy.
Be sure to wear the proper safety equipment for the following.
Now that you know how much of the stringer(s) require replacing the work can begin. The first thing is to gain access to the affected area which means removing the engine, transmission and what ever else may be in the way. (that was easy for me to say) Then clean and degrease the area to be repaired.
Now the cutting can begin. If only a section of stringer requires replacing, you will want to use a lap joint to join the old stringer to the new at both ends. One way to accomplish this is to use a reciprocating saw (Sawzall) and cut into the top of good section of stringer about 12 - 16 inches from the rotted section. Make this cut on a 45° angle toward the rotted section and cut until you are almost half way down the height of the stringer then turn the saw until you are cutting parallel with the stringer at half it's height. Continue this cut until you are close to the rotted wood then turn the saw down again at 45° and continue the cut to the bottom of the stringer. Do this at both ends of the section to be replaced. Now run the saw along the bottom of the rotted stringer as close to the hull as possible and remove the stringer. If the entire stringer is rotted and in need of replacement the lap joint cuts will not be required.
Now comes the dusty part. To finish preparing the hull for the new stringer, use an angle grinder with a coarse soft disc and grind the remaining vertical fiberglass down flush to the hull. Then grind the surrounding hull area 4-6 inches each side of where the stringer was to expose a good surface for the new resin and roving to stick to. Do this to the ends of the original stringers that you're joining to as well.
Making a pattern for the new stringer. Using a cardboard cut out the shape of the new stringer required. Use the old stringer or the opposite stringer for reference. Be sure to get the engine and transmission mount locations as close as possible. Don't panic if there not perfect since these mounts can be adjusted.
Many people will choose a standard size piece of wood to cut the stringer from which is not my preferred method. I'll explain how I build stringers and leave it to you to decide which way is better for you. Transfer the stringer pattern onto 3/4" and 1/2" marine plywood and cut out enough pieces so that they achieve the required thickness when stacked together. If the stringer is longer than the available lengths of plywood be sure to stagger the joints. Laminate the pieces together using West System resin with 406 adhesive filler or equivalent adhesive and clamp together until cured. Now locate on the stringer where the engine & transmission mounts will be. At these locations, notch out the stringer and epoxy in a piece of hard wood for the mount to sit on and bolt thru. The hardwood should be as wide as the stringer, longer than the mount by an inch at each end and at least an inch thick. Now dry fit the stringer in place and make any adjustments to ensure a proper fit in the boat.
Bedding the stringer to the hull is not a necessary step however it will provide maximum strength for your stringer repair. When installing the stringer, wet out the bottom edge of the stringer, including the lap joints, with resin as well as the joint areas in the existing stringer and the hull. Then mix enough resin with adhesive to fill the gaps in the lap joints and between the stringer bottom and the hull and install the stringer. The next step is to lay the fiberglass roving over the stringer and seal it all really well with resin.(cut the roving out around the mount locations) Use a fairly heavy roving and use as many layers as required to build up the desired thickness. Be sure the roving overlaps the old stringer and hull well into the prepared areas. Make sure that you work all of the air out of the roving.
Once cured and cleaned up you can reinstall the engine.
These instructions are based on you having existing skill in mechanical, wood working and fiberglass. If you have any further questions, myself and many other people on this site are always willing to help.
Good luck,
Be sure to wear the proper safety equipment for the following.
Now that you know how much of the stringer(s) require replacing the work can begin. The first thing is to gain access to the affected area which means removing the engine, transmission and what ever else may be in the way. (that was easy for me to say) Then clean and degrease the area to be repaired.
Now the cutting can begin. If only a section of stringer requires replacing, you will want to use a lap joint to join the old stringer to the new at both ends. One way to accomplish this is to use a reciprocating saw (Sawzall) and cut into the top of good section of stringer about 12 - 16 inches from the rotted section. Make this cut on a 45° angle toward the rotted section and cut until you are almost half way down the height of the stringer then turn the saw until you are cutting parallel with the stringer at half it's height. Continue this cut until you are close to the rotted wood then turn the saw down again at 45° and continue the cut to the bottom of the stringer. Do this at both ends of the section to be replaced. Now run the saw along the bottom of the rotted stringer as close to the hull as possible and remove the stringer. If the entire stringer is rotted and in need of replacement the lap joint cuts will not be required.
Now comes the dusty part. To finish preparing the hull for the new stringer, use an angle grinder with a coarse soft disc and grind the remaining vertical fiberglass down flush to the hull. Then grind the surrounding hull area 4-6 inches each side of where the stringer was to expose a good surface for the new resin and roving to stick to. Do this to the ends of the original stringers that you're joining to as well.
Making a pattern for the new stringer. Using a cardboard cut out the shape of the new stringer required. Use the old stringer or the opposite stringer for reference. Be sure to get the engine and transmission mount locations as close as possible. Don't panic if there not perfect since these mounts can be adjusted.
Many people will choose a standard size piece of wood to cut the stringer from which is not my preferred method. I'll explain how I build stringers and leave it to you to decide which way is better for you. Transfer the stringer pattern onto 3/4" and 1/2" marine plywood and cut out enough pieces so that they achieve the required thickness when stacked together. If the stringer is longer than the available lengths of plywood be sure to stagger the joints. Laminate the pieces together using West System resin with 406 adhesive filler or equivalent adhesive and clamp together until cured. Now locate on the stringer where the engine & transmission mounts will be. At these locations, notch out the stringer and epoxy in a piece of hard wood for the mount to sit on and bolt thru. The hardwood should be as wide as the stringer, longer than the mount by an inch at each end and at least an inch thick. Now dry fit the stringer in place and make any adjustments to ensure a proper fit in the boat.
Bedding the stringer to the hull is not a necessary step however it will provide maximum strength for your stringer repair. When installing the stringer, wet out the bottom edge of the stringer, including the lap joints, with resin as well as the joint areas in the existing stringer and the hull. Then mix enough resin with adhesive to fill the gaps in the lap joints and between the stringer bottom and the hull and install the stringer. The next step is to lay the fiberglass roving over the stringer and seal it all really well with resin.(cut the roving out around the mount locations) Use a fairly heavy roving and use as many layers as required to build up the desired thickness. Be sure the roving overlaps the old stringer and hull well into the prepared areas. Make sure that you work all of the air out of the roving.
Once cured and cleaned up you can reinstall the engine.
These instructions are based on you having existing skill in mechanical, wood working and fiberglass. If you have any further questions, myself and many other people on this site are always willing to help.
Good luck,
Paul
"Cruise Control" 1978 F-26HT
"No Control" 2012 9' Grand RIB
"Cruise Control" 1978 F-26HT
"No Control" 2012 9' Grand RIB
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Surf and Sand
- Registered user
- Posts: 23
- Joined: Mon Jun 07, 2010 5:52 pm
- Location: Daytona Beach, FL
-
Surf and Sand
- Registered user
- Posts: 23
- Joined: Mon Jun 07, 2010 5:52 pm
- Location: Daytona Beach, FL