Page 1 of 1

OT16 Otter completed

Posted: Mon Aug 08, 2011 3:01 pm
by Justin Pipkorn
There are a few pictures of the 15'6" pulling boat I completed in June 2010 at http://gallery.bateau2.com/thumbnails.php?album=1197.

The boat lines were based on 1985 plans by Joe Dobler but with many simplifications and materials of the Otter 16 plans by Jacques Mertans. I added some of my own features drawn from my experience building a 7'3" version of the Dobler Pepita. The first launch was the rowing version. Later, we motored with a 2HP OB. A gunter sailing rig was completed in time to attend the Cedar Key small boat get together in May. I am still working out some of the details and improvements.

Re: OT16 Otter completed

Posted: Mon Aug 08, 2011 4:03 pm
by Rick
Justin -- that is a pretty boat. I've been in love with the design ever since reading Thomas Firth Jones' book and it's a pleasure to see some better photos than Jones had to work with.

Re: OT16 Otter completed

Posted: Wed Aug 10, 2011 1:26 pm
by sds
Nice. It's good to see a rigged out OT16 on the water. Much appreciated.

A lithe craft, marked by effortless grace.

Keep the pictures and reports coming Justin.

Re: OT16 Otter completed

Posted: Sat Aug 13, 2011 9:59 am
by mindunderwater
Wow - what a great looking boat; I can tell there was a lot of work put into it. I just ordered plans for one of my own - building should start as soon as I get back in town next weekend and you've really given me a boost in the morale department.

Re: OT16 Otter completed

Posted: Sat Aug 13, 2011 3:15 pm
by Justin Pipkorn
If you are building the Otter, perhaps I can make a few suggestions or answer any questions.

Re: OT16 Otter completed

Posted: Sun Aug 14, 2011 10:27 am
by mindunderwater
Thank you - I am sure I will need a guide along the way.

I was planning marine fir for this application, fully glassed to prevent checking. It's either that or pay $40 / sheet more and drive a few hundred miles to get it from what my research shows so far.

Thanks in advance.

Re: OT16 Otter completed

Posted: Sun Aug 14, 2011 2:57 pm
by Justin Pipkorn
I think you are at the point of the nebby here that starts out thinking cheap plywood. What follows next if you check the posts here is that 5-10 posts will tell you for a variety of reasons that finding good plywood is worth the trouble. Most new potential builders surrender.

I was faced with the same problem in 1988 when I started Just Right. Amazingly, I couldn't find appropriate plywood in Los Angeles. Okoume is now much more widely available. I know bateau stocks marine grade plywood and will ship to your door. Even better, for some boats, they even cut out the panels and kit the boat. I'm not sure whether they are set up to cut out the Otter.

The Otter uses 1/4 inch ply. I used 4MM for the side panels. I used a little more glass than I would now recommend and my boat still weighed about 130 pounds. I estimated that I saved about 14 pounds by using the 4MM ply. Building out of 1/4 fir might bring the weight up to almost 200 pounds. Once in the water the extra weight isn't that important but when handling the boat in and out of the water less weight is helpful.

Re: OT16 Otter completed

Posted: Sun Aug 14, 2011 4:23 pm
by mindunderwater
I am hardly an expert woodworker, nor am I made of money - in fact I'm a poor guy :). I guess it comes down to diminishing returns. 50 or so lbs one way or the other isn't going to make or break me, or change whether I build the boat. If the checking issue can be resolved with 4oz cloth I'll do that. I strongly prefer to glass the entire hull anyhow. I've even set about figuring out if it could be vacuum bagged (I've done wing panels before in a class). In the end will the cost be the same as the more expensive panel and weigh more? Maybe. But I bet it's a lot stronger too. Me I'd rather grunt more lifting than sweat more whether I'm about to put my fat foot through the side of my pretty new boat :)

I may be able to work in a trip south (Houston) to pick up marine grade Okume panels. I'm no fool I know the pros and cons here. I do believe in diminishing returns; if they're going to be $85 / each for 1/4" I'm afraid I'll have to find another building method, find an alternative or just give the idea up wholesale.

Finally - there's a strong feeling here that there will be a 'next boat' - and that next boat is likely going to be 100% marine fir ply (weight is far less critical on this hull - and it calls to be 100% fabric and epoxy encapsulated anyhow) in the panels so I will need these techniques under my belt.

Re: OT16 Otter completed

Posted: Sun Aug 14, 2011 5:53 pm
by Justin Pipkorn
I was going to suggest that you just cover the bottom with glass and flowcoat the sides. We have kayaks built this way and they have held up just fine. Weight was really important here.

I notice that Meranti in BS1088 or 6566 are much cheaper than Okoume and you could get get around the checking problem. I The quotes for 1/4 marine fir that I found were near the price of meranti.

I understand now your reason for experimenting with fir. The first boats I built used AA marine fir and AC exterior. I didn't own them long enough to get an idea on durability.

If you have any other questions, let me know.

Re: OT16 Otter completed

Posted: Sun Aug 14, 2011 11:29 pm
by mindunderwater
Excellent information - I agree that the cost of Meranti makes that alternative at least a viable one. Probably lower TCO there than glassing, too. It would only be a $10 / sheet premium over local price for fir and that includes the shipping (we have a terminal where I work so that helps).

Well - orders will be made soon enough and we'll see how this goes :) For now my 'practice' project is waiting on an epoxy order and I have some plans to study.

Thanks, and again - wonderful boat.

Re: OT16 Otter completed

Posted: Wed Aug 17, 2011 12:00 pm
by Justin Pipkorn
Bow MOld for OT16

I noticed in pictures of the completed Otters that sheer line at the bow seemed to droop. I discussed this with Jacques and he provided a bow mold which he said would hold the bow shape. You might want to use the mold as shown below.

Image

He also suggested that I could assemble the sides as designed and then take a thin batten and scribe a sheer line that I liked.

Have fun building the boat.

Re: OT16 Otter completed-sailing pix

Posted: Mon Sep 12, 2011 4:05 pm
by Justin Pipkorn
Image

I added some pictures of the boat sailing in moderate breeze.

http://gallery.bateau2.com/thumbnails.p ... 197&page=1

We have been waiting for weeks for some reasonable wind on Crescent Lake to try the sailing rig. The wind finally arrived so we had a chance to see how the boat really sails. We took these pictures in light wind. (First attempt, the wind lightened up and I had a pleasant row back to the dock.) A week or so later, we had a much nicer breeze, probably 5-8 K. The boat really moves effortlessly. We were able to tack the boat easily with more wind. I was a little concerned that the long narrow hull might be hard to tack. Once the boat starts moving, she points pretty well. The daggerboard is fairly small but the designer put it in the right place...the boat tracks without much weather helm.

The automatic kick-up rudder does what it is supposed to. Once the blade hits bottom, the rudder kicks up. The overcenter shock cord holds the rudder down or up. I added a little HDPE toe on the daggerboard so it wouldn't get too banged up.

The gunter rig seems to work just fine. I use a belaying pin as a halyard cleat. To lower the sail, I just pull the pin and let the yard fall into the lazy jack/topping lift that you see in the pictures.

Re: OT16 Otter completed

Posted: Mon Sep 12, 2011 4:15 pm
by sitandfish
Beauty! 8)
Image

Re: OT16 Otter completed

Posted: Mon Sep 12, 2011 4:16 pm
by Cracker Larry
Very nice :!:

Re: OT16 Otter completed

Posted: Mon Sep 12, 2011 4:19 pm
by jacquesmm
I am impressed by the shape of the gunter sail. Those sails are difficult to cut and difficult to set but it looks really good on your boat.

Re: OT16 Otter completed

Posted: Tue Sep 13, 2011 3:15 pm
by Justin Pipkorn
Actually, I was quite disappointed with the sail. For some unknown reason, the sailmaker didn't allow for a luff round. The sail was also about 6 inches short on the hoist. After I rejected the sail, she asked to have one more cut at the sail. I had measured the mast bend so I worked with her to add the panel you see on the front of the sail. You are right though. Seeing the sail up in these pictures makes it look fair. The sail is very flat which may not be too bad considering how narrow the boat is...heeling isn't good. In the light air tests so far, the boat ghosts along with very little effort due I expect to the long narrow waterplane.

The first cut, the sail was made with a very precise cutout allowing for the thickness of the yard. The sail fits in a groove on the yard. When the luff was recut, we just ran the tape the length of the sail and ignored the cutout. This worked just fine.

Re: OT16 Otter completed

Posted: Tue Sep 13, 2011 10:42 pm
by gstanfield
Beautiful build Justin, she makes me want an Otter :D

Re: OT16 Otter completed

Posted: Wed Sep 14, 2011 10:57 am
by Justin Pipkorn
Go for it George. The Otter is my second retirement project after the VG20. Certainly a versitile boat. I still have some resin and two sheets of plywood left!

Re: OT16 Otter completed

Posted: Wed Sep 14, 2011 11:01 am
by gstanfield
After I get moved I will be building a row/sail boat for camping and cruising the smaller lakes. The OT16 is definately on the short list of possibles...then again the "short" list is still pretty long for me :lol: :lol:

Re: OT16 Otter completed

Posted: Thu Sep 15, 2011 10:53 pm
by bondo
That boat does make for a pretty picture. Looks fun. Very nice Justin.

Re: OT16 Otter completed-seat modifications

Posted: Tue Jul 02, 2013 5:28 pm
by Justin Pipkorn
I just completed modifying the seat layout in my OT16/Lissa.

Image

I sailed, motored and rowed my boat named Lissa. I decided to change the seat layout for several reasons.

ROWING: The original removable aft seat with the seat box used for the single rower position meant that I had to find a place to store either item when the other was used. The movable seat means I can position the seat for either one or two rower conditions. Yet untested is whether the seat will stay in position when I am rowing. The seat can be removed entirely if moved all the way forward.

SAILING: The original plan was to sit in the bottom of the boat when sailing. I'm nearing my 80th birthday and changing position fast enough to balance this narrow boat stability presented a challenge. Besides, the seat or seat box was always in the way. In order to reach the tiller, I had to sit too far aft which caused the boat to be stern heavy. After years of sailing with a tiller, the side seats seemed more natural. I'll see what works out when I sail the boat next time.

MOTORING: Once again, I need to sit father forward to balance the boat. I sold my Vagabond and the 2 HP Honda with it so until I get another OB, this part of the experiment will be on the back burner. The motoring that we did wetted my appetite for some more adventures which are beyond the distance I can row. I am eyeing the Suzuki 2.5 OB. I experimented with a steering line around the boat but I think a tiller extension will be my first try.

POTENTIAL CAMP CRUISER: Actually, I entered a Duckworks contest for a Puget Sound Cruiser using a variation of this boat with side seats and a small outboard. http://www.duckworksmagazine.com/06/contest/7/index.htm Now that I've have a little experience with the real boat, I think this variation may be an improvement. There are so many little cruises possible here in Florida that this boat may work out for that purpose.

Re: OT16 Otter completed

Posted: Tue Jul 02, 2013 10:44 pm
by bondo
That is really nice Justin. The concept is great and the execution is too. I bet it works perfectly. Hey what happened to that contest? I remember your entry.

Re: OT16 Otter completed

Posted: Thu Oct 31, 2013 7:23 pm
by John Larkin
Hello Justin,

First time poster here. I also am planning to build the Lissa/Otter and was thrilled to find such clear pictures of your pretty boat. I hope I can ask you a few questions. I have purchased the plans for the Lissa and have redrawn them in 3D CAD to adjust the sheer and bow shape a little.

1. I want to use a balanced lug rig and am curious if the gunter as designed at 60sf area is too much, too little or about right for sail area. I'd like to go bigger, like 72 sf unless you think that might be over-canvassed.

2. Did you build the sail and daggerboard as designed? Does she exhibit much weather or lee helm?

3. I am planning 4mm sides and 6 mm bottom, would you still recommend this? I will probably go with 6 oz cloth on the outside and 4 oz on the inside for strength and paint longevity. I also want it to be light enough to pick up and move around.

4. How many sheets of each thickness ply did you need?

many thanks in advance,

John Larkin

Re: OT16 Otter completed-Larkin Questions

Posted: Tue Nov 26, 2013 12:04 pm
by Justin Pipkorn
Sorry to delay an answer. I've been busy with other projects.
First time poster here. I also am planning to build the Lissa/Otter and was thrilled to find such clear pictures of your pretty boat. I hope I can ask you a few questions. I have purchased the plans for the Lissa and have redrawn them in 3D CAD to adjust the sheer and bow shape a little.
Let me be clear. Are you using the Otter or Dobler Lissa plans? I had both sets and used parts of each. Since I wanted to use 4MM on the side panels, most of the lines for my boat came from the Lissa plans. I believe the bottom panel for the Lissa was a little wider than the OT. I followed the interior framing of the Otter which was much simpler than the Lissa. I built the boat in a "basket mold".
1. I want to use a balanced lug rig and am curious if the gunter as designed at 60 sf area is too much, too little or about right for sail area. I'd like to go bigger, like 72 sf unless you think that might be over-canvassed.
Because of the errors made by the sailmaker, my actual sail is less than 60 SF. When I was considering the build, I was impressed with the reported performance of the lug rig on the Goat Island Skiff, a boat about the same size. I did some low grade graphics comparing the gunter and the lug rig with the same 60 SFA. It seemed that the sail centers of effort were very close. The mast, as I remembered, was longer than the 10 foot spars for the gunter. Another boat of interest is the lug rigged SCAMP. This boat has been pretty highly developed in kits and hardware. I would track down how the SCAMP rig was rigged and in particular how the reefing rigging was finally worked out. The Lissa is over a foot narrower than the GIS or the SCAMP and the shape is conducive to rowing not sailing...tippy! Going forward in the boat to reef the lug rig is chancy. I decided to add the side seats so I could shift position more easily and balance the boat. I have only sailed the boat once since completing the seat mod. I definitely would build the boat with the seat modification.

In short, I think the lug rig would be a good choice. The sail can be dropped by just lowering the halyard. Given a SCAMP like reefing system, the sail should be manageable. Although one wouldn't choose the LISSA as a performance sailer, the reports of the lug rig on the GIS indicate the lug rig is no slouch.

As to sail area, I think 60 SF is fine. The hull is very easily driven in light air. In even moderate air, the boat is scary fast downwind. Having even a little sail area on the windward side could help.
2. Did you build the sail and daggerboard as designed? Does she exhibit much weather or lee helm?
I followed most of Dobler's plan for spars as soon as I figured them out. The daggerboard is also Dobler's design. Joe claimed the board might kick up in shallows. Jacques was skeptical. I haven't sailed the boat enough to comment on weather or lee helm. Mostly, it has a different feel. The length of the hull/beam seems to have some effect here. The bottom has enough rocker that the boat responds easily to the helm. My daggerboard board is rather small but carefully shaped so the boat has to be moving to avoid side slip. The board is about the same as I used in the 7-3 version of the Lissa. In that boat, the board could have used more area...about 12 in chord x 24 inch draft when compared with the race-able Sabots [an 8 foot pram like the D5].

If I were starting from scratch, I probably would have built an off-center centerboard along side the side seats. Dobler has a plan for a pin-less centerboard that might have been ideal... and simple.
3. I am planning 4mm sides and 6 mm bottom, would you still recommend this? I will probably go with 6 oz cloth on the outside and 4 oz on the inside for strength and paint longevity. I also want it to be light enough to pick up and move around.
I followed Jacques' fiberglass schedule, 12 oz biax, one layer inside and one out. He was striving for a very tough boat. My hull weighed about 200 pounds before the seat modification. The 6 oz/4oz was what I used in the Pepita, the 7'3" version of the Lissa. That little boat was very stiff. Particularly with the seat modification, I think the Lissa would be just fine with that layup and you would save considerable time and materials in fill and finish.
4. How many sheets of each thickness ply did you need?
I used 2 sheets 4 mm, 2 sheets of 6mm plus a part sheet of 9 mm and some scraps of 6 mm. For the side seats, I used the better part of a 6mm and part of the 9 mm sheet. The nesting of the Dobler Lissa got four side panels out of two 4 mm sheets. I wonder how long Joe spent fitting that on the drawing. He was working with graphical methods... before CAD.

Let me know if you have further questions. I think your suggested ideas are on the right track.

Re: OT16 Otter completed

Posted: Fri Dec 06, 2013 6:46 pm
by John Larkin
Justin,

Thanks for the great information! I have read and reread your comments several times and they are super helpful. Thanks so much for taking the time to do that.

John Larkin

Re: OT16 Otter completed

Posted: Tue Dec 17, 2013 8:31 am
by Justin Pipkorn
John,

Keep us posted on your build.

Let me know what sail rig you choose.