Fixing a Cracked Seat

Finally found some time to update the fix for the cracked seat, which I had discovered quite some days ago. Spent some time on the web trying to work out a course of action, but finally decided to jump into it. The manufacturer had provided a little bit of information, which was of limited help.

Seat Materials: Polyethylene CYi705 outer shell + unknown UV inhibitor, with foam inner core.

Material Observation: The polyethylene can get pitted and scratched fairly easily. I’ve found quite abit of black “shavings” that were produced from the repeated insertion and removal of the seats from their sockets. As the seat sockets are made of hard aluminum, they generate quite abit of black shavings. Also, under normal usage, the polyethylene may warp as seen below. At the time of this post, the seats have been with me for only about six months.

Design Observations: The seats are essentially 2 halves – an upper half and a lower half, with the upper half sitting over the lower half. As seen below, the sides of the top half has been folded down, to overlap the sides of the bottom half (which have been folded up). Both halves are then spot glued together.

As recommended by Stephen Harbour, I used a 3mm bit to stop drill the crack to prevent it from progressing. Out of interest, I then wedged the cotter pin in the crack to see what was behind it, and…

….I couldn’t see a damn thing! Where’s the upward folded flap from the bottom half? So I swiveled over to the opposite side, and….

 

….there was the upward folded side! Hmm….seems to me that this seat had an unequally folded underlying flap, which led to the cracked corner on the opposite side being hollow and perhaps weaker. Might be a good idea to premptively check all the seats and fill out all the hollows I can find.

My assessment of the crack was that wasn’t weight bearing. In the picture below, the pressure marks (indicated by the tip of the cotter pin) show where the aluminum seat socket contacts that seats, and the crack is no where near that area.

And since I could not get under that outer flap to fill up the hollow behind the crack, I decided to slap on some Goop and worked it into the crack with my finger as best as I could, including the vertical gap between the downward folded flaps.

Not the best way to deal with this, and certainly not the prettiest. But if and when this issue reemerges, I’ll speak to the manufacturer again who have stated that the seats have a 5 year warranty.

Fair winds

Lengthy Support

The new center support for the second thwart seat finally arrived, and I’m feeling really good. This new support was sent to me by Porta Bote, in response to my issue with the “Suspended” Thwart Seat.

Considering my location and the time zone difference, I’m really impressed with Porta Bote’s outstanding service, their willingness to engage with customers directly, and their patience in answering emails even in the middle of their night. A big THANKS to Sandy and team!

The package actually arrived on 14th May, but I was on the road and could not attend to it. Checking on the support….

….hey those good chaps in California sent me an extra inch! 😀  The new support is over 13 inches long! A quick recap:

My original issue had been that there was a 1 inch gap between the original 11 inch support and the hull….

….and I was told that a support 1 inch longer would be sent my way. But instead of a 12 inch support, I received a 13 inch support.

Bonus material? 😀

But seriously, I think this 13 inch support is going to work, and here’s why….

While preparing for a launch last week, I had noticed that the second thwart seat had developed a bit of a sag. This was only visible when I place the second seat parallel to another seat.

See how that second thwart seat (on the left) is slightly curved compared to the seat on the right? In this picture, both seats are placed upside down, which means that the curve is actually a downward sag.

(Personally, I suspect that the sagging has occurred because the seat has been suspended for too many trips.)

So here’s why I think this 13 inch support might work

If the original center support on that second seat is 1 inch off the hull, and

If that very same seat has a slight downward sag, then perhaps

The 13 inch support will overcome the 1 inch gap and reverse the downward sag?

I don’t know, and I’m hoping that the 13 inch support fits nicely this weekend. I suppose the factory didn’t custom tool a 12 inch support for me, but instead took one of their bow seat center supports and sent it my way. That was probably the fastest, most cost-effective solution, as they already had the part on the shelf.

And heck, if this new 13 inch support works, Porta Bote could easily solve this suspended seat issue which several 14′ owners have already reported. The factory doesn’t have to tool 12 inch supports for owners who have this issue, and they could very rapidly roll out this fix to all affected owners. Win-win situation for everybody.

We’ll see what happens this weekend when I launch again.

Oh by the way, the very second thwart seat in discussion here has started cracking. It’s a small crack running along the top corner (the seat is upside down in the picture), and I don’t think it’s related to this center support issue. All the same, I’ll stuff some epoxy in that crack, and we’ll see what happens next.

Fair winds and supported seats, my friends!

Researching the Flexi-Splay Effect

I’ve been doing some reading on the California Portabote Group, and it appears that my unnerving experiences with the “Flexi-Splay” effect has been documented by other owners for quite some years. Even though they used different expressions like “bowing out” and “side flaring”, their experiences pretty much matched mirrored mine.

Excerpts:

• Graham Smith, Australia (post 3711)

I noticed that at one point, when the boat was planing and getting up to maximum speed, the edges bowed out as if the boat was going to collapse from the centre. One gunwale was almost under the water. It looked as if the only thing stopping it folding up was the pin in the middle seat. The seat itself was almost out of the bracket. When I grabbed both sides of the boat and pulled in, the speed of the boat increased by 2 to 3 kilometre per hour. When I moved to the back seat the sides returned to their normal upright position.

• donkrauss (post 3716)

I took it out this morning and watched the gunwales as I throttled up. At around 10 MPH the gunwale over the center seat begins to move outward. AT 13 mph it has moved about 5 inches. I had never noticed it before. On mine the starboard side is more pronounced, probably because there is more weight on that side.

• CTBoter, USA (post 4542)

I have had some concerns when I’m in rough water by myself sitting in the back seat. That would make 300+ lbs. (motor, gear and myself) in the rear third of the boat. I still have draft but it is close. I recently made an extension for the tiller so I can move my driving seat to the middle. This is the best position because I can access the entire boat comfortably. The problem is now when I’m at full throttle the right side is pulled toward the water. I try moving my weight around and it doesn’t seem to make a difference. Has anyone else experienced this?

• Mike, USA (post 3812)

Then, we put the 9.9 hp Mercury on it; with our same load, the boat quickly accelerated to over 17 mph, but was starting to deform above that speed, with the left gunnel bending way out. The boat still seemed to handle ok, and was undoubtedly still safe, but my bride was uneasy watching the deformation, so we didn’t try to go faster.

• barrymallen2 (post 19045)

…my max useable speed was about 13mph. After this the bottom sucked down under the middle seat, the sides started to bow out and spray came over the sides. Yes I could get 18mph with one up but the boat was in my opinion unstable at any speed over 13mph.

• Zack S. (post 16223)

…the left side flexes out at max speed. The right one stays upright. Even when the boat isn’t moving at all, the left side bows out in the middle by a couple of inches. The right one does not. Not planning to add a bigger motor, I have a 6hp and it’s plenty for me.

• Jay, R, USA (post 9629) – 1st Incident

I was waiting for delivery of my new 14ft PB and had not yet sold my 12ft PB. I traded in my 6hp 4 stroke for a new 9.9 two stroke Tohatsu so had to try it out on the 12. I got to tell yea, NEVER TRY THIS!!
There were no problems as long as I had a couple people in the boat and only ran the motor at half throttle, beyond that the sides of the hull would start to deform drastically.
After I dumped everyone off on the beach I decided to take the boat out by myself and see what it would do without the extra weight. I slowly increased throttle toward WOT but never made it, the bow all on a sudden began to fold back on itself. As soon as I saw this happing I cut the power, but it was just shy of having the bow in my lap; the hull was never the same.

• Jay, R, USA (post 7741) – 2nd incident

I’m going into my 3rd year with my 14 footer and only have one complaint, the port side bows out around the location of the forward ore locks at high speed. I can minimize this problem by running a line between the forward ore locks, thus preventing the sides from bowing out;  This is not a problem when there is only one person and a little gear in the boat, but when you add another adult or two the situation manifests itself, and only at high speeds. I’m running a 9.8hp 2-stroke so I’m within the boat power limits. Other owners have voiced similar concerns so I don’t think I’m alone here.

The above posts documented basic information about the incidents, but (generally) did not include information on hull length, hull series, on board load balancing, outboard size, speed, throttle level, and surface conditions. (The assumption here is that every little factor adds to the equation.) There were also other owners on that same group who hinted at the issue or made passing references, but who never documented the specifics of their personal experiences. I skipped those to focus solely on the reported incidents.

In response to some of the above posts, the manufacturer reminded the group of instructions in the owners handbook (post 3726).

6. “FLEXING”: When you step on the “floor” of your boat, you will notice a certain amount of flexing in the “floor’. This is normal. Also, when the hull begins to “plane”, the sides will flex out and the floor bottom will flex “down”. This, too, is normal. This “flexing action” actually absorbs and cushions much of the impact of strong waves that might capsize an ordinary rigid hulled craft. The transom will flex, also. However, if one or both of the sides of the hull begin to flex or deform “abnormally”, you are traveling beyond the “MAXIMUM SPEED CAPABILITY” of the hull. Immediately reduce engine rpm. This flexing will stop and you will find you are traveling at almost the same speed, comfortably. (NOTE: No matter how large an outboard you install, your Porta-Bote hull cannot go any faster than its “MAXIMUM HULL SPEED”. It will just start to flex abnormally.) Never try to make a sudden “sharp turn” when traveling at high speeds in this or any boat.

Which is fair, logical advise. Folded hulls can never have as much rigidity as solid hulls, and this hull wasn’t made for outright pace.

Having said that, there will be situations where slowing down is not a logical option, either because of obvious danger (in the form of the Weserwolf), or because speed is already way low.

Did you see the size of that bow wave? 😀

In both my incidents, load management as well as prevailing sea conditions were the key triggers rather than speed or throttle position. We had launched on back-to-back days to clock up the required 10 hours run in for the Tohatsu outboard, and throttle position had to stay between idle and 75%. In no way could speed, torque, or sudden acceleration have been an issue.

Here’s the run in schedule for the Tohatsu M9.8B. My first incident happened in the third hour, while the second incident happened in the eighth hour.

There will be days where one needs to boot the craft to get out of danger, or perhaps to get back to shore in a hurry. On those very days, I wouldn’t want the hull to splay and slow me down, or (worse) bow out and start taking on water.

The search for a fix continues.

Fair winds

Hull Perspectives I

The very first time I assembled the boat, I had discovered that long objects could be placed flat across the second and third seats, but not between the third and fourth seats as the fourth seat was slightly higher than the third seat. I thought nothing of this height difference, and simply accepted it as part of the hull design.

In the course of investigating the suspended thwart seat issue, I discovered the reason why the fourth seat is higher than the second and third seats.

See those brackets for the seats sitting just above the C-Beam?

The stern brackets for the fourth seat are a full inch higher than the brackets for the second and third seats.

In perspective, this is where the stern brackets are in relation to the C-beam

And this is how close the second and third brackets are to the C-Beam. Not even half a finger’s space, and I don’t have fat fingers.

I thought to post these findings, as it might have several implications.

1. Those stern seat brackets are raised higher than the other seat brackets,
   perhaps to allow the stern seats to use the standard 11 3/16 inch supports rather than a different part (which would be more expensive from a manufacturing standpoint)
2. Since the 11 3/16″ supports on the third and stern seats contact the hull perfectly (at least on my craft),
   it follows that the midline depth of the hull gets shallower as it approaches the stern.
3. Which would probably mean that the reverse is true, as in
   the midline depth of the hull gets deeper as it approaches the bow
4. Which would then clearly explain why I’m having the issue of the suspended second seat (which is using an 11 3/16 inch support)

Porta Bote has very kindly offered to send a slightly longer support my way. I’m really delighted with their rapid response, and I can’t wait to receive it and get back out on the water. Won’t have to jam umbrellas or stuff under that center support any more.

What Hinges Beneath & Behind

Finally managed to make time for some measurements. Several parties had requested more info, so here we go (excuse the poor photography).

• Sandy from Porta Bote requested for specific dimensions of the center supports

All the center supports for the second, third, and stern thwart seats come in at 11 3/16 inches, metal edge to metal edge.

The center support for the bow seat came in around 13 inches as mentioned by Dave, but the front support was never the issue.

• Separately, Dave requested information on the transom locking system (L-pins vs 4 bolts). There are some pretty good clips on Youtube depicting both systems.

L-pins transom (scroll to 3:38) by RUDYAKAHALIBU77
4 bolts transom (scroll to 2:20) by Fiskkonservator

This is my transom, and the motor mount looks like it’s holding up fairly well after the last incident. Excuse the debris from the last trip.

As depicted in the two YouTube videos, the transom is interlocked into place, and the motor mount then folds over the stern ‘bladder wall”. I did notice some marks on the “bladder wall”….

….and eyeballing the gap between the transom and the motor mount, we see the rivets responsible for the marks.

Time will tell what happens next with those marks.

Thwart Seats and the Hinged Supports

This is an update on the suspended seat issue that I’m having.

Another Alpha 1 series owner Dave has very kindly confirmed that when he first received his craft, the side supports did not contact the corners firmly, and that he had to adjust the hinge position. This was exactly what I experienced, and I presume that most new owners are expected to adjust their side supports.

But that’s not the issue. The issue is that beneath the second thwart seat, the support does not contact the hull. even when the hull is on the water.

I’ve taken some pictures of my seats for comparison. Sorry about the poor quality.

1) The three aft thwart seats are all the same length and thickness.

2) The supports are all of the same length at roughly 11 inches. This length does not vary for center or side supports

3) The hinges that hold the supports are all at the same positions

4) The only variance in the pictures above come from my shifting of the side supports to different hinge postions.

I am now truly lost about what I should do next, and I suppose it is best I write to the manufacturer. Again, should you have any ideas, I would welcome all thoughts and recommendations.

Cheers