Bob's Special Strongback question

[hoosieratc]

I have decided on building a Bob's Special for my first canoe this winter. I am going to be ordering plans within the next few weeks. Was wondering if using the plans out of Canoecraft for the 16ft strongback would be ok for this canoe, or should the strongback be shorter since the Bob's Special is only 15 ft long. I would like to have the strongback built by the time the plans arrive.

Plan on using 3/4 in plywood for the strongback and 1/2in plywoof for the forms. Any different suggestion on wood for the strongback or forms would also be appreciated.

[Glen Smith]

I find that a strongback that is one foot shorter than the boat serves me better. The stems stick out a bit past the ends of the strongback making it easier to work at the ends of the boat.

Your choice of wood is good although I normally use particle board for the forms because plywood often has voids which can be a nuisance if you are stapling the strips. If building without staples, plywood is fine.

[Arctic]

I built my strongback 1 foot longer than my 15' Hiawatha- 6" extra on each end. So far it has worked out well in giving me space to work with at the ends. I used 3/4" pine for the strongback and 1/2" plywood for the molds- I am using staples and they have all held well so far- I am now well past the bilge and on to planking the bottom of the hull.

Mark
Cantely, Quebec.

[Scot T]

Hello,

I'm with Glen on the shorter strongback, although I built my Hiawatha on the 16 footer. I think it would be a little easier to work on the ends of the boat with a half foot off each end of the strongback. And I have a small shop so the extra unuseable space would have been a bonus. Every little bit counts when the space is tight.

But I don't plan to end my canoe building with a 15' boat. With that in mind I opted to stick with the longer strongback so I don't have to build another or adjust this one to make a longer canoe.

For the plywood for the strongback and forms I sprung for some better quality plywood. There were a couple small voids in the forms but I filled them with wood pieces before starting to strip the canoe. For me the extra cost for better materials was/is worth it. I always think you get a better soup (canoe) if you start with the best ingredients you can find.

[Juneaudave]

I used a 15 ft strongback (BearMountain design) when I built my Bob's Special. Worked great! I prefer 1/2 inch. particle board for the molds as opposed to plywood. I find it's a little easier to shape and is a lot cheaper. Particle board will last for several canoes....if I were to be making 3 or more of the same design on the same molds, I might go back to plywood.

One note on particle board...be sure to use particle board and not MDF. MDF is too hard. Happy building!!

[WayneM]

Hoosieratc

I used 3/4" MDF for my 15' Bob's Special strongback (contrary to Juneaudave's advice) because it was on sale when I needed material. It worked great and was easy to fair the molds etc. but cripes is it a heavy strongback. Two of us struggle to move it in and out of the main shop. I used an electric stapler adjusted to the right staple depth and found it worked very well. It appears that the molds could easily be reused a few times as well. For the weight problem alone, I would change materials if I was to re-build a strongback. Or, I may keep the strongback as is, but change the molds to lighter material for the next boat. Good Luck.

[sedges]

When I built my second hull I knew that I would be building a bunch of boats. I mase a 20 ' long strong back with a clear yellow pine 2x12 for the top. I have my 13th or 14th boat on it now(I seem to have lost count).

I like the extra length. Its a place to put tools, glue bottles, etc. The longest hull made on it was 18'10". I do have plans for a 20' rowing boat called the Bangor Packet, so I guess I'll use the whole length some day.

[clicksys]

Now Ithis first-timer is confused. I'd like the SB to serve for more boats in future. To work on the stems, I assume I want the SB shorter than the canoe, OR I'll need to extend the risers on the molds by a few inches. Should I build the standard 16' SB and raise the molds for the first boat (which is 15'6")? Or should I cut the SB short, and plan on changing the SB length as nec. for each boat? It looks like I could extend risers and still cut the molds for this boat from a 2' piece of plywood. Canoecraft says the SB should be the same length as the boat, but actually shows one that is shorter than the boat being built.
Perhaps I'm obsessing, but its a substantial investment of time and materials to build the SB, and I'd like it to be right. Thank you!

[sedges]

I knew that I would be building a variety of boats up to 20-22 feet and I only had space for one strongback. I have to make sure all the molds are tall enough so that the peak of the stems will be above the strongback. This takes a bit more plywood, or whatever material you use for molds, but you'll never have to build another strongback.

The one thing I have had sifficult with is the height of the strongback. The first boats I built were normal sized 16 foot tandems and smaller. Then I built a big tandem and now a sailing dinghy and find it difficult to each the middle of the boat without standing on a riser. I am going to work on an adjustable height strongback, maybe even make it hydraulic or screw lift operated.

[Glen Smith]

My strongback is 14' long and I made a removeable 2' extension for it. So for I have used it to build a 15' canoe, 2 kayaks 16.5' , 1 kayak 14' , 2 kayaks 13' , 1 canoe 10'. All without difficulty. Just make sure that the molds or risers are high enough so that all parts are at least 2" above strongback surface or the stem tips extend beyond the strongback about 6" so you can work on them.

[David James]

If I ever need to build another strongback, it will be built with two "engineered lumber"
"I-beams". You can use the I-beams (positioned horizontally) for infeed and outfeed platforms in front of and behind the table saw when ripping those long strips. The box beam worked well for me but I won't build another... Just my two cents worth.

Dave, in Glenview, Il

[Juneaudave]

If I ever need to build another strongback, it will be built with two "engineered lumber"
"I-beams". You can use the I-beams (positioned horizontally) for infeed and outfeed platforms in front of and behind the table saw when ripping those long strips. The box beam worked well for me but I won't build another... Just my two cents worth.

Dave, in Glenview, Il

I think that is really a good idea especially if you are a first time builder and need in-feed and out-feed tables for ripping strips!!

[David James]

Thanks Juneaudave, now if I could only learn to use fiberglass and epoxy!
Dave

[Woodchuck]

Dave, you should have won the Suggestion of the Week Award for the idea of using the halves of an adjustable strong back for in/out feed tables. I have plans, some wood, tools, etc. but have not started making my strips. What to do with the in/out feed was a concern and I resolved myself to making some temporary rollers as opposed to buying more of the metal stand up ones. Now, no problem... I will make some adjustable legs for the stong back halves and cut all I want... Great idea and one that saves money as well as improves on the quality of in/out feed tables... Thanks again...
:eyebrows :smile

[John Michne]

Don't those engineered beams have a slight crown in them? I may be wrong, but I seem to remember seeing something about how great they were for spanning long distances in house construction, but there was a definite top and bottom. They should make a great strongback, but be aware of a possible crown.

- John