Stabilizer mounts finished

As it turns out, as I wrote my last post, the seat post clamps I needed to finish the stabilizer mounts were sitting on our front porch.  I was able to add these to the arms yesterday.  I needed to file about 1 mm of material off of the tube to leave space for the lip on the inside of the clamp.  This usually serves to keep the clamp from slipping down the seat tube.  Here it also helps keep it in the correct position.  I also drilled a small stress relief hole opposite the 3/8" snap button hole and used a hacksaw to create a slot about 1 inch long up to the small hole.

I got the clamps in position and I would say they work well.  They will keep the parts from moving with regular motion of waves, but they can still be moved since the lever arms are so long.  With the weight of the clamps, the full assembly is pushing 13 lbs, but there is no extra stuff on the hull except for thread inserts.

After getting the full assembly together, I became a little concerned that my last minute change to allow split mounting and independent height adjustments might have compromised the strength more than I expected.  The photo here shows the two halves joined together.  There are a series of holes 3/8" apart to allow about 1 1/2" of movement in each direction.  I guess if I had planned ahead and knew the direction of prop rotation I really would have only needed to adjust in one direction, but there was enough space for both.

The two halves create a "V" that will nest with the fairing on the seat back.  The long slots will allow overall height adjustment with 4 knobs threaded into thread inserts in the seat back.  Now that the full assembly is together I have a better appreciation of two things.  First, the stabilizers are a little heavier than I was expecting at 5 lbs each.  This doesn't seem like a lot considering I used a minimum of epoxy and glass, but the second thing I have a better appreciation for is the feel of hanging 5 lbs on the end of a 3 ft lever arm.  It would have been an easy calculation, but I admit it wasn't something that jumped out at me having never used a boat with outriggers before.  Needless to say now, the long lever arm causes the bracket to flex quite a bit at the two fasteners holding the halves together.  Fortunately, I did fiberglass inside and out of both bracket halves so the panel joints will be secure.  This flexing should be improved a bit when there are 4 extra fasteners holding everything to the hull, but it could still be an issue.  I guess worst case, once I arrive at the offset I would like, I can re-glue the halves together permanently in this position.  I'll have to try it to see.

Overall, I like the ease of folding the stabilizers up behind the seat.  I am hoping that I can also raise the bracket high enough to put the stabilizers on top of the rear deck, otherwise they will hit the sides a little and I will need to bungee them in place so things don't bump around.  With the 4 fastener knobs holding the whole thing on, if I do need to cartop the boat, I can easily remove this weight and save my back when I lift the 55+ lbs I expect the rest of the boat to weigh.


Time to this point (everything including repeating steps): 120 hours

Details, details...

The devil is in the details with boats as much as with anything else.  I have made quite a bit of progress on the front end, where it turns out there are lots of small details.  I have finished off the hand holds.  I have made the little covers for the gearbox.  One covers the opening to slide in the gearbox into the slots, and another covers a small access to the first shaft bushing and the shaft collar to make leg length adjustments in the shaft coupling.  I suppose if I had used a top mounted gearbox, these would not be necessary, but I still like the look.  I imagine once I have forgotten about the extra few hours it took, I will be happy I did it this way.  

I've also added threaded inserts to two places for standard bicycle water bottle cages.  One set is on the front panel adjacent the forward hatch opening.  The other is on the top between the gearbox and seat.  For these bottle bosses and small access panels, I used small brass thread inserts.  It turns out I had to modify them to make them secure in wood without spinning free in moderate torque.  I think my modifications have worked and now that I chased the threads with a tap, the fasteners fit in easily and shouldn't create much torque. 

I have also nearly completed the hatch coaming for the forward hatch.  It has 10 small magnets seated into the material.  There will be matching pairs in the cover and a thin gasket.  I'm hoping it will seal reasonably well, but the fact that the cover is curved is not in my favor to achieve anything watertight.  It's something to consider for a future refinement, but I think the only time water will reach this high on the deck in any amount will be in a capsize, and then the inside might get wet, but shouldn't get swamped.  However, I'm not sure I can realistically get the actual hatch cover done in the next week, which is my unofficial deadline.  We have a trip next weekend I would like to use as a maiden voyage, and if all goes well I would like to go to the Rockford Hydrobowl the weekend after and "compete" against other boats.  It is a race, but with equal parts informal fun.  I can tape up the opening if I am worried about flipping.  As long as I can enjoy a few runs before winter, I can get it 100% finished later.

Once the last few coaming gluing steps are complete, the remaining forward deck and seat will be ready for final epoxy fill coats, and then finishing.  As far as the rest goes, I have the stabilizers painted and complete and the brackets and beams painted and only waiting for the seat post clamps I decided to go ahead and use to eliminate all slop from the moving parts.  This post should come soon.

I have also spent a considerable amount of time reworking the back of the seat.  I was originally hoping to use this space as a large cargo space with a hatch in the seat back behind the cushion, but I would say in the rare case that the front cargo space won't fit what I need, I can easily bungee a dry bag to the back of the seat.  Also, this arrangement added significant windage, and lastly, the panels fit together with a lot of twisting to accommodate the multiple angles of the seat back.  This proved very challenging to fixture during gluing and it is not something I would like to repeat.  Since I hadn't fit the rear fairing to the hull and was dreading this as well, I decided I would just try what I wish I had done.  So far so good, but it isn't done yet.

Because of my reworking, the time tracking is more complicated.  I'm up to about 110 hours, but 10-15 of those have been repeating steps or making changes that could now be done up front at the CNC shop.  I'm getting close, but I had hoped the whole process would be about 100 hours.  I imagine I am in good company of those who underestimate the time it takes to make a new design of a wooden boat.

Stabilizers finished

I've been feeling more productive this week, but it is still a lot of effort to finish up what seem like "accessories".  Right now the stabilizers are essentially ready for finishing.  I will add a final epoxy coat and then a final sanding.  I am leaning towards painting the stabilizers to save some time vs varnish.  It will be the first time I have ever painting anything after making it in wood, but perhaps it's a good time.  I am starting to think that the stabilizers should be made from laminated foam core (Rick uses Klegecell).  I have weighed the wooden stabilizers and they come in at 5 lbs each, 6 lbs with the mounting arms and brackets.  It would be a significant weight savings using foam and the panels all fit nicely on one sheet anyway.  In this case, they would be painted, so maybe I should see if it looks good.

The stabilizers were fabricated in a similar way as the main hull, but I was willing to save some weight on the lamination steps since it is unlikely that the stabilizers will have any major impacts and need the same strength as the hull.  For these panels, I coated the inside with epoxy but no fiberglass.  I added a fillet to the inside corners but no glass tape.  The outside was fully laminated, but I used 4 oz cloth rather than 6 oz cloth.  It is the first time I have tried this weight.  It is noticeably thinner, so I imagine it took less epoxy to wet it out.  I don't know if this was significant.  I think it might be appropriate to use this weight for other inside areas, maybe the inside of panels above water line, again since there is little risk of impact, but it would still seal the wood and improve stiffness.

I have glued the mounting tube studs to the stabilizers.  These go through the top and nest into a piece of plywood glued to the bottom.  I assembled the mounting arms and held them perpendicular to the stabilizer while I drilled a 3/8" hole for the snap button.  The holes were a very tight fit, so I was able to slowly file the hole larger until it was just big enough to fit the button without any binding.  With this minimum clearance, it results in about 1" of play at the end of the 3 foot arm.  I think this will be acceptable since these will be primarily skimming the water.  I will just have to try them out.  If it does bother me I can add a slot to the outer tube and a clamping collar, probably something like a seat tube clamp on a bike. 

Total time to this point: 90 hrs

Stabilizer mounts

I have had another rather unproductive week.  Since our son was born late last year, my free time is generally limited to nap times on weekends and after bedtime.  It is also limited to the times when I am not sick with the various germs he brings home from daycare.  This past week we shared multiple rather tenacious viruses.  Slowly we are getting back to normal.

I have started working from the gearbox to finish up the hull, but I had run out of epoxy and needed to wait for more to arrive.  I had a little left of a different brand, so I am using this for the stabilizers so I can avoid mixing.  The boat will be a trimaran, but the stabilizers will be positioned to barely touch the water in calm conditions.  I am using a slightly different stabilizer mounting design from previous versions of Rick's V15.  There are a few use considerations guiding the design.  One is that I live near enough to a lake that I can walk there using a dolly and car topping will be infrequent.  This means I would like to keep all the pieces together for the walk over, and have a very easy assembly process.  My boating outings are also limited to short windows, so every minute saved in setup is an extra minute on the water.

To keep the pieces together I am using a some nesting tubing so the stabilizers can be rotated out of the way.  The snap button will have two positions, one for transport and one for use.  The nesting sections will be vertical and will be joined by a 3 ft horizontal tube.  A secondary benefit to having a vertical mount is this provides a few extra inches of wave clearance.

The fiberglass tubes are all purchased from a small kayak paddle manufacturer.  The nested tubes are originally made for two-piece paddles, so the fit is very good.  The mount at the main hull will be located at the vertical edge of the seat back fairing.  This will allow for height adjustments based on rider and cargo weight.  I have also made a late modification to use a split mounting bracket so each side has independent height.  Based on trials from Rick, he points out that the propeller torque is high enough at cruising speed that the boat can list slightly.  One way to offset this is to lower the stabilizer on one side.

 So far, I have used a small drum sander drill attachment to create the "fishmouth" shape on the tube ends.  I used gel epoxy and set up everything to bond parts square.  Afterwards, I used scrap wood for gussets and applied fillets and glass tape over this for reinforcement.  It should hold up.  I will be painting these components, including the brackets.

Since the last post, I have also stitched and glued most of the stabilizer panels and the bracket panels, but I will put these photos in a later post.

Time up to this point: 75 hours

Joining the forward deck

It feels like progress has slowed because a lot of the work has gone to joining small pieces and reinforcing internal seams that won't be visible, but on the upside it is looking a lot more like a boat.  I finally was able to join the rest of the forward deck onto the main hull.  Using stitches wasn't realistic because it was going to rest on the edge of the splash guard where panels come together roughly in a Y shape.  It took some creative use of clamps and a few borrowed hands to help temporarily align things, but the pieces did get persuaded into position.  I used gel epoxy on these seams as well.

The tricky part came next.  The footwell areas need to be securely bonded to the hull because it is possible I will stand directly in these areas.  This meant applying glass tape to the inside seams.  Fortunately, I did not assemble a small vertical panel on the gearbox mount, and this allowed access to the underside.  It is also fortunate that I have long arms.  In this case, I did not want to have to sand a cured fillet all the way inside the hull before applying the tape, so I did both in one step.  I applied the fillet, mostly blindly, with a syringe and then smoothed it out.  Before the fillet cured, I soaked the tape in epoxy and rolled it up.  I unrolled the tape, again mostly blindly, and smoothed it out.  The advantage of combining these is that you can smooth out any lumps in the fillet while smoothing out the tape, rather than beforehand by sanding.  There is a risk it could become an even bigger mess if something goes wrong, but it is a good option in some cases.  I could shine a flashlight inside from behind the seat when I was finished and confirm that the tape was roughly in the right place and was free from large bubbles.  Once the tape was cured, I reached back inside with sandpaper and gave the tape edges a quick sanding.  This is too prevent any cuts if I need to reach there in the future.  Not surprisingly, the rough edges can be as sharp as glass.

A recommendation for the future is to evaluate a similar design but to attempt to reduce potential windage issues from the large central panels.  It should be sufficiently rigid to use an L shaped rectangular beam that extends from the seat to the gearbox and angles down to the deck.  This would leave more open area.  I think it could also create useful open storage area for water bottles and a mesh pocket or similar.  I doubt I will modify this one, but I will think it over.

Now it is on to more small details.  I am creating two hand holds on the sides of the seat.  I will add small half-round wood trim to the bottom for a smooth grip.  At some point I will figure out a way to place a rudder control inside this recess so it is easy to reach without repositioning my hands too much.  This will probably wait until the end.

I will also need to figure out a way to close up the main forward deck opening with a hatch.  I've been reading about some nice wooden hatch covers secured using rare earth magnets.  Maybe I will try this, since tension straps won't be very practical in this position.

 Time up to this point: 62.5 hours