We recently had the opportunity to test drive a Lehr outboard on the PT 11 nesting dinghy. http://golehr.com/lehr-marine/
I should say up front, that we are personally anti-outboard for this boat. The PT 11 is lightweight with a hull shape well suited for easy, near effortless rowing, even for longer distances. The sailing rig is also very easy to use. Our vision has been that this dinghy can be a tough, utilitarian, and totally enjoyable alternative to inflatables, as tenders for cruising boats.  Even so, the PT 11 can be used with a small outboard.  We have calculated that a 2HP outboard would be plenty of power to move this little boat with ease and also keeps the PT 11 within a certain USCG category.

In our opinion, however; those who expect to use a motor on their dinghy more often than not, might be better off with a different dinghy. One could choose a boat with a fuller aft end. Rowing performance would be compromised but these boats would plane with a 5HP motor.
There are, it seems, few, new model outboards of 2HP or less.  Most outboard producers currently have models of just over 2HP. Other than the perceived "need for speed" from the general public, we are not sure why they have chosen to discontinue lower HP motors. See a PT 11 test drive with an EP CARRY.
For the sake of experiment and because this motor was offered to us for this purpose, we went ahead and made a test drive.  Thank you to J.S. for this opportunity.
Here is what we found and there is a link to a short video at the the end of this post.

I. Motor: New Lehr 2.5HP propane outboard. ( 15” shaft, cost: roughly $1050)
Port Townsend Watercraft
II. Weight: We feel like this motor is quite heavy at almost 39 LBS(incl small 1 LB gas bottle)

III. Noise: Moderate.

  • Comparison:
  • On forums online, the Honda 2.3 has been proclaimed as very noisy.
  • Electric motors are obviously the most quiet.

IV. Speed: The Lehr 2.5 propelled the PT 11 with a single, 180 pound operator, at 6.8 knots, at full throttle in protected waters.

  • No comparisons at this time.

V. Trim: The PT 11 is light weight. The weight of the motor being nearly half the weight of the boat, and with a single operator having to sit far enough aft to reach the tiller, causes the bow to ride high. One would need a tiller extension to be able to shift driver weight forward.

Port Townsend Watercraft
Taking off at full throttle..

VI. Mounting: The outboard was mounted with a raw mahogany block just below the inwhale. For the purpose of this demo, we adhered it with double sided tape. For more permanent installation, we would advise exchanging the bolts on the top gudgeon, for screws that bite into the block. On the outside of the transom, we used raw mahogany strips. The block and pads are to prevent crushing or denting the hull skins when tightening the clamps.  For a motor this heavy, we recommend re enforcing the transom with vertical ribs adhering to the buoyancy tank walls and butting up to the underside of the inwhale. This would be light and effective. Port Twnsend Watercraft

Port Townsend Watercraft

VII. Conclusion: In general, if you are set on mounting a motor on the PT 11, it is preferable to choose a motor that weighs less than 30 LBS. We will be making some effort to mount and test drive the Electric Paddle in 2014.
Click here to see a short video of the PT 11 with the Lehr 2.5HP.   PTW 😉

Note: If any of our builders have tried a small outboard on your PT 11, please contact us with your experiences.

UPDATE: This information was sent to us from one of our builders in Florida. The HP used exceeds sanctioned HP for this boat but the results are informative.

"Today's Sea Trial:  Salt water, 75 degrees, sea level, iPhone GPS.

POWER:  2.5 HP (rpm restrictor removed to increase to 3.3 hp), 1990 vintage two stroke, factory propeller, 27 pounds, Mercury outboard with tiller extension.

Life jackets, paddle, no additional gear.

Top speed, one 140 pound operator, 10 mph.  
Top speed, two people 330 pounds, 8 mph.
Top speed, four people 810 pounds, 6 mph.

Ideal cruise "sweet spot", two people, 6 mph.

Boat exceeded all expectations. " (Video below)

 

Russell and all of our design consultants have a lot of experience with wood and epoxy boat building and a lot of thought and science went into making sure our boats are designed to be both light and strong. No boat is indestructible of course, but please consider carefully any modifications and feel free to consult us if you have concerns based on your planned use of the boat. We may not have a full time tech line but we do try to be available for customer concerns.
There are lots of ways to personalize your boat but please do not attempt to alter the structure. Also, a well built Pt 11 is a valuable boat and modifications could negatively affect resale value.

Boat building is a creative process. With our kits, it may be said the Russell has thought of 'everything' and thus, the margin for builder inventiveness is limited. I beg to differ and I have great faith in each person's ability to creatively personalize their boats! It is also our hope that the building experience in itself serves the creative spirit well and the end result is a boat that makes the builder proud and happy. It is difficult to make guarantees, and especially so if any part of the design and/or the described building method, is omitted or modified.
In reference to some questions we have received ;
Flotation vs Storage;  about the PT 11: The three compartments, one in the bow and the two in the stern, are completely sealed flotation and have the same value as foam flotation in this type of boat. If access ports to flotation compartments are installed, equal foam flotation would then be required to replace the sealed air. This would be a lot of work and totally pointless. Trying to use designated flotation compartments as storage can be dangerous if the boat flips or floods. On the PT 11 & Spear, there is a large storage aft of the mast step with ample space and the PT Skiff has 3 separate storage areas. We had to calculate flotation for the PT11, the non nesting PT SPEAR, and the PT SKIFF in order to satisfy the USCG safety guidelines. It is the builder's responsibility to abide by those rules, and, it is just plain smart.

Re-enforcements; Any additional wood or glass than what is prescribed in the manual, serves to add weight and will not necessarily make the boat any stronger than designed. Our boats are already designed with heavier glass on the bottom and solid fiberglass caps on the skegs for added toughness. If it is expected that the dinghy will be typically dragged over rough landings rather than carried, one could beef up the fiberglass on the bottom further, but it will add weight.
The transom, as designed, is strong. The rudder is a kick up rudder so there should be no chance of ripping off the transom of the boat with this rudder. If you plan to use a small outboard, (max 2HP) you would use bearing strips on the outside and clamp pads on the inside.
Builder resources; Our PT 11 family is growing. This is very exciting for us as we are a small company of just Russell and myself. Even more exciting is that our customers have been building beautiful boats! This year, 2013, we  established a registry of sorts (see the map) as an owner/builder resource and aim to create an interactive community. (see our Builder  Center page) The questions, comments, shared experiences of each builder are all welcome material that I will look forward to adding to the blog for others to learn from and enjoy.  Our heartfelt thanks to our customers, followers, and friends who share their opinions and enthusiasm about our products. We would not be here without you.

PTW Ashlyn

Having a bailer in a dinghy is a very important thing. Dinghy sailing in gusty wind can get wet, especially if the captain is not paying attention and dips the rail. Russell came up with a handy bailer idea. ptwatercraft.comThis oblong fabric softener bottle offers both a wide mouth scoop and a low profile that fits neatly below the seat tongue. Stashed inside for minor spray is a sponge. This green sponge was a waste of pennies. It does little more than spread spray water. A good absorbent sponge like this PVA sponge or 3M C41 7456-T is a much better choice. I personally like these pop-up sponges but they do not hold up well if left outside, which is kind of the point environmentally.. 😉 DSC09645This bailer installation does not interfere with nesting. There is room to spare. We used carbon glue on eyestraps and a bungee cord to keep the bailer stored out of the way but within quick reach.

If you capsize, sweeping the water out with your arm or sloshing out the water before getting back in gets most water out. See it all on this video.  PTW :-) PT Watercraft website

 

 

Experiment 2012 to create a kit for oars: High density foam and carbon fiber blades. Unfortunately, these kits would end up being very expensive as they require a lot of time and effort on the part of Russell. With all that he has to keep up with, this kit would not make sense for us. We have decided to leave oars to oar makers but thought you might find these pictures interesting. Please see our oars links page for oar resources. Do you know of oars that you really like? please let me know so I can add a link to the links list! Thank you.

ptwatercraft.com1

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ptwatercraft.com7; finished oars. solid epoxy edges. Douglas fir shafts.

Would you like to make your own oar blades and small hardware? Russell has published an e-book /book about working with epoxy. More detailed topics are on the agenda for future publication.  Have you seen our e-books/books page?

PTW website

The order forms on our website arrive in my inbox as detailed emails listing what you want to order. This is how the ordering conversation begins. Periodically, I receive forms that have been filled out except for the contact information.  I do not know the html to make the form refuse to submit without your contact info so if you do not hear from me within 24 hours, please contact me.  Periodically, these forms come in without any way for me to reply. (today for example)

Please be sure to fill out the contact info on the order forms! Only then can I answer your questions. 😉  thank you! AEB

Advance your epoxy skills and waste less, sand less, and achieve beautiful results. Russell's many years of experience have taught him more than a few valuable techniques.  This full color 40 page e-book covers the basics of gluing, filleting, glassing, and coating. You can check it out Here.  We also have an affiliate program set up if you would like to carry this handy book on your website.  EpoxyBasicsCoverThumb

 

This article was written a while ago and somehow lost on my computer. When a recent wooden boat discussion showed up about flotation in boats, an intense search prompted by Russell's certainty that I had written on the subject, turned up the 'untitled', and thus, 'lost', document. So here it is.

The USCG’s “Pool of Truth”
Testing the PT SKIFF  (Ashlyn E. Brown)

In June of 2010, Russell and I embarked on a cross country road trip. We would not have done this except for 2 compelling reasons: an invitation to the Woodenboat Show in Mystic, CT and the chance to have the PT Skiff tested by the USCG.

The USCG has regulations for various classes of boats, and contrary to common belief, kit boat companies have the responsibility of providing a product that, built as designed, will pass federal requirements.

The PT Skiff falls under the category of “under 20ft outboard powered motorboats”. The rules for this category are particularly stringent due to a higher number of fatalities on record occurring on boats in this class. With ski boats and other high speed recreational boats under 20ft, this is not really surprising. So they have devised a method for testing motor boats under 20ft in a tank with 2 careful procedures.

First, the USCG wants to be sure that the rated capacity and HP of a boat are acceptable. To physically check this, they load a boat with 5 times it’s rated capacity or until the boat is about to submerge. For the PT Skiff, the former would be 6000 LBS. The computer images below demonstrate the displacement with 6000LBS and the maximum 9000LBS before submerging. These calculations were submitted to the CG headquarters and they agreed that our capacity label of 6 persons or 800LBS, or 1200LBS persons, gear & motor, was a modest rating.

The second critical test is to show what happens when a boat is totally flooded. This is called the Flotation and Stability test. ptwatercraft.comsimulated 6000 Lbs in the PT Skiff (Image by Eric Jolley) ptwatercraft.comMaximum Capacity of 9000 LBS (Image by Eric Jolley)

We arrived at our family’s home in Virginia on June 10th and took a couple of days to recover from the long time on the road and dip the skiff into the Chesapeake. ptwatercraft.comTouring the East River of the Chesapeake in the PT Skiff. Photo Ashlyn Brown

Over the weekend, Russell removed the motor and controls in preparation for the testing. We had been talking with the gentlemen at the CG about the testing procedure. While we were not concerned about 6000 LBS being loaded into the boat, we were a bit shocked to learn the method; blocks of pig iron weighing 800LBS each, measuring 1’x 2’x 2’ loaded into the boat. Further discussion revealed that the point load would be on the 1’ x 2’ base. The man in charge promised to stop the loading if he heard any “cracking”.

Russell spent the weekend considering any possible way to spread the load.  To put this into perspective, just one of these pig iron ‘blocks’ weighs more than twice the weight of the PT Skiff and, still roughly 1.5 times the weight even with motor & controls. They would be loading 5 of these blocks and then some. The lightweight construction of the skiff could get very stressed with that kind of point load and even the designers were concerned.  What about  smaller blocks or sand bags? we asked, or Water bags? We would cover the cost, we offered. No. They had their method and at this time, they were not set up to do it any other way.ptwatercraft.com800 LB, 1ft x 2ft x 2ft blocks. Photo; Ashlyn Brown

On the appointed day, with some trepidation, we drove to Solomon’s, Maryland where the one and only USCG testing facility is located, somewhat incognito, in an unmarked warehouse. We were greeted by a team of 3 middle aged men who scrutinized the boat on the trailer while we discussed our options. It was at this time that we learned that the capacity ratings had been accepted by headquarters so that the load test, while recommended, was totally optional.
On the one hand, we badly wanted to prove the boat and the method of build as capable of point loads such as this. On the other hand, if it did go ‘pop’, we would not have a boat for the boat show a week later, and this was most definitely, the only time we would be on the east coast with it.  Had the test been scheduled after the show, things would have looked different, but that was not the case. We were told that we could later make our own (albeit 'unofficial') load test that would verify the calculations.

The flotation and stability test remained and once the decision was made, our hosts relaxed and invited us to return at a given time to observe the test.
When we got back, they had the boat in the slings inside the building and were weighing it; 388 LBS.ptwatercraft.com

The PT Skiff weighed and ready for the “pool”. Photo; Ashlyn Brown

Next, a basket with lead weights was mounted on the transom to match the weight of the 25HP and other weights under the console and driver seat to simulate batteries etc.
They lowered the boat into the tank, which was a swimming pool measuring about 22ft x 10ft. All air voids were opened. In most boats, they have to drill holes but our air voids all have deck plate access. Hoses filled these areas first. The slings were then totally removed and the water continued to rise until it broached the back seat and ran out the scuppers. At this point, our host, demonstrated with red food coloring, the outflow from the scuppers and declared that the boat would not hold more water.
Now the boat had to ‘sleep’ flooded for 18 hours before the rest of the test could be done. We could come back early the next morning.ptwatercraft.com

PT Skiff totally flooded and floating level. Photo; Ashlyn Brownptwatercraft.com

Food coloring to show outflow of water. Photo; Ashlyn Brown

We walked from our hotel, across the little inconspicuous  bridge that proves this is an island and followed the singular street to it’s end where it loops back. The place definitely had an island feel to it with full marinas, lots of tourists, a big waterfront boardwalk, colonial style buildings housing stores with tropical patterned clothes, a Kontiki bar and plenty of restaurants. Russell had been testing the vanilla ice cream across country and here was no exception. We sat in the shade of a little umbrella and gave our critiques on his ice cream cone and my smoothie. It was very hot but it had been since we crossed Wyoming. The Chesapeake can boast a particular kind of hot that once experienced, is not to be forgotten in a lifetime by one’s sub-conscious senses.

We also strolled through the maritime museum and admired it’s collection of old local skiffs and fishing boats, long and narrow things of linear beauty that understood efficiency once upon a time.

We ended the day by having dinner at the Catamaran restaurant since they had an outdoor balcony. From there we could watch the sunset while idly eaves-dropping on a group of locals discussing, what else but, sex, parties, and politics. With the thick summer heat, the mellow southern drawl, and the chain smoking, our north west home felt far away indeed.ptwatercraft

Sunset in Solomons, MD  Photo; Ashlyn Brown

We arrived at the testing facility by 7:30 AM and the crew was already at work adding water to the flooded skiff just to be sure she was properly topped off.  The sling was put back on to support the boat while Steve carefully stepped into the boat and placed carefully calculated weights in prescribed locations to simulate the presence of people. They explained that they would move the weight around as if the passengers were to one side or the other, simulating a ‘worst case scenario’, and then measure the list of the boat with the slings removed. For outboard propelled boats, they should float fairly level with a maximum list is 30 degrees. In contrast, for boats with inboard motors, stability is not key but they do have to have some part of the boat above water in order to pass. This could be no more than the tip of the bow. No amount of explanation of this could make sense to me but those were the rules.
While I’m not the most technically minded person, Steve was a very good teacher and he explained every step and the concept behind it. He and his crew worked patiently and systematically as they recorded data, took pictures, worked with the electric winches, passed weights back and forth and stepped up to the waist in cold water. These guys had a good sense of humor but they also took their job very seriously and worked together like a well oiled machine.
By the end of the test, the PT Skiff listed a maximum of 11 degrees and all had gone extremely well.ptwatercraft.comFilling the boat with water. Photo; Ashlyn Brownptwatercraft.comStarboard maximum list. Photo; Ashlyn Brown

We picked the skiff up a couple hours later after they had pumped it dry and loaded it back onto the trailer. Steve explained the report he would prepare and best of all, calculated our mileage from Port Townsend and typed up a bill in our name. That’s right. Volunteering to have a boat tested is a paid deal and we got our check about 2 months later. Why do they pay you? Simple. It is cheaper than buying a boat. When new boats get red-flagged or there is any suspicion that it might not pass, these gentlemen buy it incognito and test it. If the boat fails, the manufacturer receives notice that it must recall all boats of this model at their own expense. Usually if the USCG goes to the trouble of buying a boat, there is already a probability that it will fail the test and there were enough boats in their shed to show that some do indeed fail.
A strong reason for re-designing the PT Skiff with side decks, in contrast to the first prototype, was to get the flotation up high; under the side decks and front deck as well as under the back seat. This not only provides better flotation when flooded but gives it the stability demonstrated by the test. Obviously, every boat could encounter conditions that outwit any controlled imitation but these tests show that the designers have taken the rules seriously and applied important safety factors into the design.PT Skiff on display at the Woodenboat Show in Mystic CT, 2010
Photo; Russell Brown

A final note; my explanation here is how I have understood the process and the reasoning behind it. Further “official” information can be found on the USCG website here (pages 16-18 specifically about flotation):
http://files.dnr.state.mn.us/education_safety/safety/boatwater/backyardboatbuilders.pdf
Or see the USCG website where there is lots of information.
http://www.uscgboating.org/regulations/boatbuilder_s_handbook/flotation_part1_f.aspx

 

THE SPEAR is identical in hull shape to the PT 11, but the interior geometry and construction are quite different and deserve explanation.  The PT 11 has a full width foredeck so that water drains into the aft compartment, otherwise there would be three areas that would need bailing of rain and spray. The Spear can have scuppers through the main bulkhead (the nesting PT 11 can’t) and therefore can have what I call a “trunk” seat.
When rowing with three, the trunk seat allows more comfortable seating for the person sitting in the bow. The areas to the sides of the seat are good for holding oars and other things in the boat.
The trunk seat also keeps the hull from twisting under sailing loads. It’s like a torsion box. (Shown below are the PT11, left, and the beta prototype of the Spear)
ptwatercraft.com

Below photo taken in March 2013 of the prototype being built to figure out the process and to write the manual.

ptwatercraft.comTwo of the watertight hatch kits that we offer as options fit really well in this boat, making the boat versatile for carrying (and keeping dry) groceries, camping gear, cameras, safety gear, etc.
The aft hatch is easier to access when sailing and is great for things like cameras, jackets, and food, but because of the baffles under the back seat (more on that next), the volume of area under the forward hatch is much greater.
While the hatches are work to install, the cost of the kits is very small compared to the utility and safety they offer. They also provide access and visibility to the daggerboard trunk, mast socket, and rudder hardware, not to mention a good place to hide valuables left in the dinghy. Coast Guard regulations play a large role in the interior geometry of the PT 11 and the Spear. This may sound like big brother getting in the way of art, but it’s quite the opposite. The regulations are to protect us, the kit provider and especially you, the end user.
Buoyancy built into the right parts of the boat is necessary for safety. Sealed air voids (compartments) have the same value as flotation foam, but access ports or hatches are not allowed in sealed air voids. If the builder insists on inspection ports, it is then necessary to fill these voids completely with foam flotation in order to comply with safety standards. The Below Photo shows the boat before the deck and back seat lid are installed. ptwatercraft.comptwatercraft.comThe bow area (forward of the mast step bulkhead) is a sealed air void in the PT 11 and the Spear. The PT 11 has built in buoyancy tanks in the back of the boat on either side (outboard) that are equal to the volume in the bow. This is what the Coast Guard wants, and it makes sense.
The Spear has a large back seat area, but because it has a hatch, we have to install baffles to form sealed air voids outboard of the hatch where they would do the most good in an emergency. Though the baffles under the back seat decrease the usable volume for storage, they make us legal and make you safer, and they make for a well supported back seat. ptwatercraft.comBelow; Rowing the Spear with 2

ptwatercraft.comThe finished boat pictured was a beta prototype built summer 2012. Due to less specialty hardware required, the Spear base kit will cost several hundred dollars less that the nesting version. The boat will be lighter by 3 - 5 pounds. The various options, including sailing rig, offered for the PT11 nesting dinghy will be the same for the Spear. As of April 2013, we are taking orders for the "SPEAR" kit.

See our website for full information. PTW:)

Every time Russell has a boat to build, he seeks better ways of doing things. In this case, a simplified method for gluing the puzzle joints revealed itself. The manual for the PT 11 'Spear' has this section but earlier versions of the PT 11 nesting dinghy manuals have an earlier method. I have created a pdf file of the 7 page replacement for pages 7 through 14 in "Building the PT Eleven" for those who have an older version and have not yet begun to build their boat. This may also be interesting to anyone building a stitch and glue kit with puzzle joints. Click  HERE to download the .pdf file.  (533kb)ptwatercraft.com