Pages

Tampilkan postingan dengan label john. Tampilkan semua postingan
Tampilkan postingan dengan label john. Tampilkan semua postingan

Kamis, 10 Maret 2016

The Strongback Advice from John Bridges

The CABBS blueprint of the strongback.
We received our plans from CABBS and started thinking about the first step to build the prams. My brother is in the process of cleaning out his garage for this project, and I havent had a lot of time to go over the blueprints. It seems pretty clear that the first thing that needs to be done is the Strongback.

I contacted John Bridges who has been building Optimists since 1963.  I saw a post comment he made on the WoodenBoat Forum and traced that back to the work he has done with the Moraine Sailing Club. 
John (brown shirt) lifting a hull off the strongback.

"I first built Optimists in Trinidad back in 1963 using the plans as published in the Rudder magazine.  I think we just set up a pair of 2" x 6" timbers on the floor as a base to work from.  Since then I have built others in Chile, Colombia and Ghana.   Some where along the line I built the present strong back here in the USA  which has been used to build about a dozen Optis out of the 17 that I have helped MSC members to build. my strongback is on legs to raise the hull to a convenient height for working and avoid to much back bending. 

The first operation is to make the centre frame and two transoms.  These will have extended side pieces so that they align with the (straight and level) datum i.e. base of the strongback.   I have the cross bearer for the bow transom, bevelled so that the Bow transom can be screwed to this and it is important that the other two cross bearers are at the correct distance from the first one.

Strongback in use during one of Johns group building projects.

I usually use ring shank Phosphor bronze ring shank nails to hold the plywood in place on the chines whilst the glue sets. Epoxy is messy stuff so we are usually using PL2 Construction adhesive these days. For several years we have used Lauan Plywood (Interior use but with Exterior glue) and have found that this lasts for at least 6 years without problems providing it is kept painted and stored out of the sun and rain.   

1948 Optimist Plans

It can be covered with fiberglass cloth which adds to weight and durability.  The USA made Pine plywood does not weather well.  For more permanence Marine Plywood is available for about $95 per sheet (cf 20 for Lauan) It is all a matter of, as we say in England "You pays your money and takes your choice".  (Johns photos)


As we get started on this project we will be posting pictures and video of the Optimist project. We hope to create a good record of our mistakes as well as triumphs.
Read More..

Jumat, 26 Februari 2016

Boatbuilding More Progress by John Z on his Classic Moth

Hull panel offsets for the Mistral can be found here.


In the ongoing coverage of John Zs Classic Moth build, last week I stopped over at his shop to gauge his progress and have a beer. The Classic Moth modified Mistral design is now upside down awaiting gunwhales and a layer of 4 oz. glass over the bottom.

This photo, though perhaps a tad distorted, shows how deeply Veed the Mistral design sections are around the midships.


Transom view with a pretty swirly pattern from the okoume plywood.


John, with the about-to-be-opened bottle of stout peeking up above the keel-line of his Moth.


A man and his workbench. John graciously took down a Marblehead RC sailboat he built many years ago so I could take a closer look.


A man and his workbench - take 2.


From the previous photo, you can see that John has some interesting stuff hanging from his walls. This is the box containing his F1 rubber-band indoor airplanes. These are extremely finicky to make, with a minimum weight of one gram. John has all the various tools to test balsa density and strength; tools to strip balsa into extremely narrow widths; tools to check rubber band elasticity; molds to make the tricky propellers, and the various techniques to apply the ultra-thin microfilm covering.  To make a F1 takes a methodical, painstaking craftsman.


John also has two half models of the Americas Cup, IACC keelboats, the class that precedes the current foiling catamarans. Surprisingly, it was through his wifes connections and not his Naval Architect circle of friends that these two half-models now grace his shop.





Read More..

Kamis, 11 Februari 2016

Interview With Boat Designer John Simpson

Interview with John Simpson 

John Simpson has been a boat designer for 45 years. I had a chance meet him at a Metal Boat Festival a few years ago. Now every time I go to one I look forward to hearing him speak. He has a vast knowledge of boat design and is always willing to share that knowledge.

John, you have been a long time member of the Metal Boat Society and contributor to the Metal Boat Quarterly, thank you for your years of support.


DB: When did you get into boating?
JS: My first boating experience was at 4 years old with my dad in an open 16 rental boat with inboard engine.

When did you realize you wanted to design boats for a living and how did you become a yacht/marine designer?
Even though I had been sketching out boats for several years and had been boating since 10, it was during a university summer job maintaining 3 naval utility vessels (75, 48, and 36) that design and construction got into my blood stream. My first step was to interview several naval architects to get a feel for the business. All were very helpful and one suggested the best path was to marry a rich woman (I didnt). I did another summer job in a boatyard leading to a 4 year marine design/drafting and engineering apprenticeship at a shipyard where we built several ferries & barges and at that time, the worlds largest semi-submersible oil rig. At completion I had jobs with several naval architects designing yachts, fish boats, dredges, barges, etc. Around 1972 (incorporated 1974) I started doing my own design work and topping up wages working with a boat builder.
Could you tell us about your first commission?
The firstwas a 70 steel schooner shortly followed by a 33 fuel efficient motor cruiser(s). Both are still in service

Since that first commission, how many boats have you designed?
By my records about 110 sail, power, commercial ranging in size from 17 to 80 in steel, aluminum, and FRP. Some designs evolved from originals so the total number is higher.
This may not sound like a lot of designs over 40+years  but keep in mind that some designs can be complicated and if they need to meet Government Regulations, must be diligently monitored throughout construction this and outside consult work absorbs time.

Not only do you have experience designing, but you have experience in building. Could you tell us about your boat building experience? 
From a bare hull: a 9 sailing dinghy & a 22 sail boat. Plus, 2 years with one builder followed by 3 years doing custom power boats 30 50, the latter as foreman, estimator, assistant manager, & designer.   

What lessons  have you learned from building that have helped with your design work?
Try not to design what one boss called an Architects Dream”… ie: impossible to build. It was obvious that the designer had no boatbuilding experience and little boating experience.   I was just getting into my own design business and my boss gave me some good advice:
 Never forget that one day:
(a)You may have to build one of your designs.
(b) You may have to use one of your designs.
I have done both on several occasions

As a designer you are well versed in not only yachts, but commercial vessels. I hope our readers will go to your website  http://www.simpsonmarinedesign.com and take a look at your portfolio. What are some of the challenges with commercial designs that are not present in recreational design?
The challenges are very similar but commercial boat (fishboats, etc) owners often push the limits, sometimes at great risk: Overloading, improper loading, or sailing into harms way, is not uncommon.  Not all boats are the same.
What are some of the challenges with recreational and cruising designs?
Very similar to commercial vessels: Different boats (designs) have different characteristics and each must be used within its limits. Putting a hot-tub on the housetop of a pontoon type house boat might be fine but on a motor cruiser, it may not be an option.

Any tips for the amateur builder looking at designs and wanting to build their own
boat?
(a)Choose the right design by getting some boating experience.
(b) Work up a realistic schedule with particular attention to time. Unfortunate as it is, I have seen many cases where the boat project outlived the builder.
(c)  Dont underestimate the price. If your dream is a $500,000 yacht, you are not going to build it for $150,000. (not to the same standards at least.) 
(d)  Concentrate on the boat and not the parts. Building your own parts (windows, port lights, engine conversion, etc.) could be a poor investment of time: That 10 year project might stretch into 20. And never get completed!
(e)  Use marine parts & equipment it is designed for that purpose. Boats equipped with automotive and/or domestic equipment may put you at risk. 
(f)    Get the other half involved- being a boat widow is not fun.
(g)  Pay nowor .. Pay later. Doing it properly the first time is a good investment. Corrections later can sometimes be very costly. If they can be done at all.



Any tips for anyone wanting to modify a design of an existing boat?
Be very cautious: small changes can sometimes have huge consequences. Work with a naval architect/designer (preferably the one who did your boat)

Could you tell us about your consulting services you offer?
This covers wide variety of services ranging from performance estimates, propeller sizing, stability evaluation, to a design check (a review of the design with a second opinion).

Anything on the drawing board you want to tell us about?
A small project for a client that did a circumnavigation in one of my designs. They want to go from offshore to inshore.  It is a 30, easily transportable sailing punt to be used for exploring various inland waters in North America & beyond.