Another Redbird and questions

geordie · Post by **geordie** » Sat Feb 04, 2006 2:47 pm

She left at last, and I got my 36’ by 15’ studio back. Plenty big enough to build my Redbird. So, the strongback is up and set, the forms are going on, and already one or two questions.
Number 7 form is up with the stem form against it. The DWL lines meet and everything is nice and square. Now, if I measure from the top of the stem form (against the 7 form) to the tip of the 7 form I measure more than the ¾ thickness of the inner stem. The total measurement is just short of 7/8. Do I, ignore this and put my faith in the good design.
Make my inner stems 7/8th thick.
Check my measurements again.
I do realise that the strips come on to the stem from the sides, and not over the top of the form, so have I answered my own question?

Anyway, this forum has already been invaluable, and you will be hearing a lot more from me over the next few months as I progress. I hope to have her ready by our summer, about September time.

Post by **Patricks Dad** » Sat Feb 04, 2006 3:15 pm

My recollection is that the difference between Station 7 and the Stem mold is indeed different from 3/4" but it's in the other direction than you have measured. Re-measuring our plans, the height of the Stem mold is 20" from the baseline to the top. The height of station 7 is 20 5/8" (actually short of the 3/4" needed for the stem material). This means that the stem will be shaped to a point by the time it reaches station 7. The 1/8" flat leading edge will vanish by the time you reach the station 7 mold (with 3/4" thick stems).

I suggest you remeasure your stem molds and station 7 and compare with the plans again.

hope this helps.

geordie · Post by **geordie** » Sun Feb 05, 2006 12:13 am

Ok Ok, first lesson learned.
Check the plans before blurting out on the forum.
Now, I overlaid the stem and station plans and matched the DWL lines, sure enough, its exactly ¾, that is, the inner stem should be flush with the tip of station 7 when fitted. I went and rechecked on the strongback, and yes, I am slightly out, but only by 1/16. (The top of the stem will be 1/16 lower than the tip of station 7).
Again, what are my options?
A slightly thicker stem? (I have not made the stems yet)
Make it up as I go along with the planking
Re check the station and stem profile against the plans.

Glen Smith · Post by **Glen Smith** » Sun Feb 05, 2006 1:06 am

If you will be making the stems out of 1/4" laminations I have found that 3 laminations will produce a stem that is slightly thicker than 3/4" when assembled with thickened epoxy. Remember, you do not clamp down so tight as to expell all the epoxy so it does have a slight amount of thickness. Then if the stems do not fit flush with the top of station 7 you should think about compensating. If stem is lower by a fraction, I might consider reshaping station 7 for a good fit. If the stems are higher by a fraction, you might want to trim a hair off the bottom of the stem mold. Neither solution will have any impact on the boat handling or look.

Its Me · Post by **Its Me** » Sun Feb 12, 2006 5:49 pm

Consider making your stems 1.25" wide to avoid having a 3-dimensional cope it in to the hull. If you haven't seen Glen's photos on how cope in a stem on Bear Mountain Boat you wan to ask him. To do it over again, I would make my stems wider and just wrasp away the extra material.