boatman’s corner

 
 

Vespoli Fin Repair:


This is a great solution to an expensive problem.


We all know the headache of novice crews knocking their fins off on the dock, putting their boat in slings, or while loading the trailer.  At $35 a pop this can be an expensive habit and it is often tough to keep a spare fin at the ready in a large boathouse.


  1. 1. The first step in this operation is recovery of the fin.   Fins broken off on land are obviously easy to recover.  Those that shear off on or near the water are a different story.  For these try this trick:   With the fin off of the boat, drill a small hole through the fin (from side to side) about 1/4” from the top and about 1/4” to the bow of the aft most brass stud.   Then tie a fishing line tether (about 2’ long) through the hole, knotting it off up on top of the fin.  Thread the line up through the aft most hole in your hull and tie it off to the rudder tube inside the hull.   Then drawing the line tight, install the fin.  Done properly, you will barely be able to see the fishing line on the fin as the knot will be buried between the hull and the fin.  For those worrying about drag, the fin is so far back from the bow of the boat that by the time the fin passes through the water the layer of disturbed water is so large that a thread of fishing line is not going to make a difference.   Now when your crew either knocks off the fin while rowing, or takes it off on the dock, the fin will dangle from the boat by its tether.    A swift yank will snap the line and remove it either for the row back to the dock or for the “walk of shame” back to the boathouse.
















  1. 2. Set the recovered fin in a vise and with a power drill and a 7/64” drill, drill a hole about 1/4” down into the center of the broken off stud.  This can be tricky and takes patience and a steady hand.  But the brass is soft and with a good vise it won’t take long to master the task.  With a hole down the center, remove the remains of the stud using a #1 screw extractor.  A screw extractor is a nifty tool that has left-handed spiral flutes on it that gets twisted into the hole in the stud.  As the flutes grab into the soft brass, the stud starts to twist out of the plastic fin.   This too is tricky as it requires that you press quite hard down onto the extractor as it turns in to make sure that it grabs and does not strip the inside of the hole.  It is a bit counter-intuitive to press down hard to get something to come up, but it is no different from removing a tough screw that is at risk of having its head stripped.  If you do do this (strip it that is), there is still hope.  A # 2 extractor will now fit into the enlarged hole and do the same job. 





                                                                                          This is a screw extractor, in a tap                                                                 

                                                                                        wrench, with the remains of a stud

                                                                                        still stuck on the end.








  1. 3. Replace the damaged stud with 10-32 4” long brass studs.  You can cut these yourself from bulk brass threaded rod, but McMaster-Carr (the online hardware emporium) has them pre-cut (they also sell drills, screw extractors, and the tap wrench that you will need for it).   You can chuck the new stud right into your drill and thread it in quite quickly that way.  Be careful though and slow down when you approach the bottom of the hole so that you don’t either strip your hole or damage your threads. 

















                                                            Fin in vise and 4” 10-32 brass replacement stud.



All told, if you have none of these tools or materials on hand, getting set up for this will cost you:


#1 screw extractor  $3.21

5/64 drill bit  $1.32

T handled tap wrench- $5

Pack of 10, 10-32 4” brass threaded rods    $10

Total cost to repair/rebuild up to 10 fins (min of 5 fins if you always break both rods): $19.53

This job pays for itself the first time you do it and can easily save you hundreds of dollars per year. 


PS.  Life gets even easier when you encounter a stud that you have already replaced.  They come out so easily that you almost don’t have to use the extractor; the drill alone can sometimes do the job as you back the drill out of the hole.  If your holes start to get “loose” after years of replacements (there must have been fins on novice eights that I rebuilt at least 10 times in my 27 years of doing this) you can solve that problem by drooling a few drops of 5 minute epoxy down into the hole right before you thread the new rod in.  Put a very light coat of oil/WD40 on the new rod to make sure that it doesn’t get too tightly bonded in by the epoxy.

This page is just getting going.  Our goal is to fill it with boat maintenance  and repair tips.