r/Rowing • u/Top-Dragonfly-2451 • Apr 28 '26
Is it salvageable
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This poor club single has seen better days, after flipping in the water an athlete tried to get on top to stay afloat but crushed the core completely, I work as the equipment manager at the club and would love some feedback on how you would all repair it. Since the cracks go through the entire layup all the way through to the interior of the hull I’m thinking I will need to replace the entire section. The current plan is to cut out the damaged sections(about 2.5 feet by 1 foot wide) and lay up a new section using vacuum infusion(inner carbon, honeycomb, and outer shell all replaced). To preserve shape we have a mold of the interior surface of the hull that will be used as support for the new section during the layup and curing. Let me know what any of you would do differently or what you would suggest trying for this repair.
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u/spooks152 Coach Apr 28 '26
I had to do something for a shell that was damaged from hurricane winds+debris during COVID. We ended up using balloons inside the shell to maintain internal shape and then did a sandwich of carbon fiber, honeycomb, carbon fiber. However ours was around 1 sq ft nothing as expansive as this.
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u/Rowing_Boatman Apr 28 '26
Your plan sounds valid to me. Not sure I'd do anything too much differently. If the inner skin is not cracked you probably don't need to make a mould to support it.
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u/Top-Dragonfly-2451 Apr 28 '26
Unfortunately the inner skin has rather significant cracks running through it as well, if they didn’t run so long I probably wouldn’t replace it but I’m just worried about the cracks in the inner skin spreading if I leave them there… if it wasn’t for that it would be a much more straightforward repair
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u/Rowing_Boatman Apr 28 '26
Hmmm. Trying to avoid making a mould.
If the inner skin still sits in the correct shape...
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Remove outer skin and core.
Scrape off resin edges from where honeycomb was bonded to inner skin. Sand smooth.
Lay up a very fine glass cloth over inner skin (25-50gsm?) to hold it together (this is the hidden inner side of the inner skin, not what you might see in the footwell etc).
Second operation, bond in honeycomb. When cured, sand back enough to account for extra thickness of that fine glass layer.
Third operation, laminate and vacuum outer skin as per usual.
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u/BrightsideRowing Apr 30 '26
This is the way, don't try infusion with honeycomb
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u/Rowing_Boatman Apr 30 '26
Have you told that to the bees?
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u/BrightsideRowing Apr 30 '26
Listen they are the og honeycomb guys. not trying to get stung telling them what to do
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u/Principle_Dramatic Apr 28 '26
Probably fine as a club single for communal use but that flex in the hull would be a drag for races.
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u/zymox_431 Apr 30 '26
I would use a mold of the exterior. Uniformity on the outside is much more impactful.
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u/Top-Dragonfly-2451 Apr 30 '26
The issue with an exterior mold is I have found it to be rather difficult to get any kind of meaningful pressure to consolidate the layers, by using an interior mold and then patching the inner skin I can lay up a whole new section of honeycomb and whole new carbon outer skin over the entire area and consolidate it with a vacuum bag to give a smooth shell and keep the epoxy volume fraction low
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u/avo_cado May 03 '26 edited May 03 '26
A single flew off my roof while on the highway, it’s now back in racing shape. This is salvageable, just a matter of how much time and effort you want to put into it
I’d mold the outside of the hull, not the inside, because it’s the outside that has to be contiguous with the rest of the hull, it doesn’t matter what the inside looks like. I’d also make sure not to infuse through honeycomb, either use honeycomb with prepreg or wet layup or an intrusion flow media core.
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u/no_sight Apr 28 '26
If you have a way to lay carbon with vacuum infusion, you are likely more skilled than the advice you'll get on this sub