half size PT hull

I got so tired of saving money to buy a boat, only to discover that the price increased. Now I'm building one. When I was in my thirties I built an airplane. Upon retirement I built a house. Without having as much as a plan I decided to build a half size PT hull. Afterwards I'll finish it off as an express cruiser. No doubt I'll need help; read five books, purchased a set of plans of a like length hull, now I've started.

I've got the stem finished and almost done with a laminated keel. There are always things that bother me though. For example, I want to put bolts through the keel laminations. I have bronze rod and it's a snap to thread it. But what's wrong with a steel bolt Grade 8 or better. I could countersink both ends and fill with epoxy. Any problems here?

I'm e-mailing from the library and may not be able to get pictures of my project on the screen.

Any help is always appreciated,

Larry Wegeman (PT Larry)

 

The hull form developed for the PT is very popular and was the main shape used in most power hulls until the 60's. I hope you haven't veered too far from the path set down by the plans you've purchased. Even something as benign as making a cabin bigger or moving it's placement on the deck can adversely effect the balance of the boat (especially true in small craft) where performance can suffer and trimming becomes difficult.

Grade 8 mild steel doesn't belong on a boat. It's quite strong, but will rust quickly even faster around salt water. Insure you have bronze rod and thread that. It's the material of choice in boat construction and will not break down like steel can. You can hammer over the end and thread the other or thread both. Don't be tempted to thread the whole thing, it'll leak like a nylon stocking bucket.

Embalming fasteners in a puddle of goo will work for a while, but then the lumber gets wet from a breach in the surface coating and swells up. This will spit out the toughest of materials, including a glob of epoxy around the head or end of a fastener, then the rust and rotting begins. Your plans should let you know what types of fasteners to use. Stick to the plans as a an amateur builder. When you've gained some experience building yachts, material substitutions can be made with a level of expertise you currently don't have.

 

Thanks. I'll take your advice and use bronze.

Hope you receive this and that I can learn how to use this website better. I'd like to edit my original message (thread ?).

 

The stem is completed and built from four pieces of laminated 3/4" marine plywood, using epoxy and bronze screws every six or eight inches. It weighs about 125 lbs. and stands nine feet from the top to the keel's horizontal.

Building the transom of two laminated 3/4" thickness of marine plywood. Needed to build a table first. Its in-the-ground sturdy and about two feet off the ground so that I can work comfortably. I'll laminate with epoxy and screw with bronze screws as I did the stem, then glue and screw a mahogany frame around it. The best seems to be 8/4 genuine mahogany. The lumber yard says they buy it from Honduras. This transom will weigh about 400 lbs., and I'm thinking ahead about how-to-move-it to the keel.

Before I started this project in December, 2004, I built a canopy in my backyard. It's 16" x 40" and supported by six 4" square steel tubings. This will keep the sunlight and rain off the project. Recently, I thought of using the very sturdy construction of this canopy to hoist members such as the transom. I also have a neighbor with a backhoe. We'll see !

I like to plan ahead and it's so easy to do stuff to the members NOW, if I know to do it. If you've been here, where I am now, please share your experiences with me. Of interest to me is lightning grounding stuff under the keel.

Thanks in advance

Larry Wegeman

 

I need a tutorial on how to add to my threads.

 

I did it.

The transom ended up weighing 720 pounds. I included two inside frames around two thickness of 3/4 inch marine mahogany. Did this to insure a good hold to the sheer. Then, I built an 'A' frame over the frame-building table and hoisted the transom moving it twenty feet to over the keel. I didn't attach it but placed it where it would attach, securing it to the ground.

Next, I built the next forward frame and placed it over the keel.

 

Then I decided to build the beam frame (bulkhead frame). To my surprise the table wasn't wide enough. At this point, I went back to work on my house. Remember I said that I built a house. Well now I'm working on the inside. Never did I realize there was so much work involved building the inside of a house. As the weather warms here in Texas, I will surely go back to work on the hull. Firstly,I will add some width to the table without losing my lines.

 

I'm Using marine epoxy to coat all the frames. Because it's not UV protected until painted, I have covered the parts with sheets, blankets, old plywood - to keep the sun off. It will take me a while to finish this project, nevertheless, I'm very enthused.

I'll be in touch.

 

Great thread Larry, please do keep posting updates

 

Yes - this applies to the inside of your boat as well. What was the saying? A finished boat-hull is only one third of the work / 30% of the costs.

 

Very true.... the hull always tends to emerge remarkably quickly and under budget. It's the fitting-out that soaks up the time and cash.... there's big stuff like engines, of course, but also cleats, winches, instruments, seat cushions, fenders, radio, etc, etc. It's certainly a lot of fun, and very satisfying when the new boat finally takes to the water. Keep us posted.

 

Good advise and encouraging too. As a retired guy these are my projects, the house and the boat, and I don't quit. Sometime in the future I want to take some digital photos and get them posted.

 

August 3, 2008 and I'm back on the job. For your information I have moved my boat project from Sunrise Beach,TX to Port O'Connor, TX, some 225 miles closer to the Gulf of Mexico. In the process, the boat is now 7 feet longer and 2' wider at the beam. I have renamed her PT 88/2+7. Photos are available to post if I only knew how. I swear it is easier to build a boat than to post on this forum. Question, true or false? When a member is encapsulated in epoxy, are all the metal parts embedded within the member immune from corrosion?

 

"Question, true or false? When a member is encapsulated in epoxy, are all the metal parts embedded within the member immune from corrosion?"

Only in a perfect world, not this one. Resistant perhaps, but not immune. Sorry. Don't be discouraged though, there are few perfect boats, but lots of good ones.

 

No boat lasts forever, and neither will mine. The next question is if the encapsulation stays in tact, might I not expect some really long life from the embedded parts. What are the problems say, above the waterline. What I am obviously trying to do is to justify the use of non-pure metals as fasteners to secure members that have also been glued with epoxy. Every sense tells me that the epoxy is what is holding the members, not the fasteners, and the only moisture that can get to them is the moisture that is already in the wood.