Showing posts with label stern. Show all posts
Showing posts with label stern. Show all posts

Bow Eyes and Stern Tiedowns

Saturday, February 20, 2016

Sometimes little things can be a big headache. And sometimes big headaches can turn out not to be that big a deal at all. And so it was with the bow eyes and stern tiedowns.

Heres the idea, I have a trailerable shantyboat. It is really really nice if when I am towing down the road if it stays on the trailer. (See Tips on how not to die in a fiery ball of twisted metal on the highway.)

So we add a few hooks into the hull that allow us to attach it to the trailer.  Additionally, the boweye will allow us to winch the boat the last few feet onto the trailer, as well as be towed if we ever need to do that.


A boweye and a stern tiedown look pretty much the same -- typically a stainless steel U-bolt that ties into the framing members of the boat. The price of boweyes varied tremendously, and not necessarily commensurate with the quality of the hardware. That was frustrating. After lots of searching online, I found a high quality, reasonably priced set of boweyes/tiedowns.

I was not that excited about drilling more holes in my allegedly waterproof hull.  Additionally, since there wasnt space within the tight confines of the boat to drill from the inside, I had to drill a hole from the outside and yet still hit the precise center of a one and a half inch framing member.  Ack.



So this required a good deal of measurement, re-measurement, guess-work, and calculation.


Word on the street is that there is a clever device to make sure that the holes you drill are perpendicular to the plane of the surface you are drilling, a kind of portable drill press.  I dont have one of those.  I used my carpenters square to ensure that my hole was perpendicular.


Despite all my calculations, you can see my first hole that was vertically positioned too high.  Inside, the hole was positioned on the framing member without enough space to receive a nut. Laterally though, my holes were perfect positioned.

I considered epoxying the inside of the holes to prevent damage if water should get inside, but only primed the holes instead.


I used the special silicone adhesive and sealant (referred to around here as the Black Goo) on the portion that would rest against the hull before tightening the boweye. .


Inside the bulkhead under the desk, I tightened down the boweye.


Cleaning up the sealant, I had a beautiful boweye mounted to the center of the bow. Rinse, repeat, and I had the stern tiedowns bolted into the members beneath the stern.



It wasnt as hard as Id feared, nor as easy as I hoped. Awesome.
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Chine ideas round stern details

Tuesday, January 26, 2016

Heres some sketches of my current thinking on my lower lifting Chines, spray strakes, and a round transom.

This is how I see certain Chines working. When running your skiff and others look at how the water flows out from under the skiff when at all angles of trim. Do this in flat water to get a good view and then in rough water to see what really happens. All small skiffs suffer from the fact that they cannot travel fast enough to get away from beam sea spray blow back. To help in this I feel you need to help direct the spray away from the hull in a downward and hopefully aft direction.

 
I use this reverse spray strake to direct the spray down. Small light skiffs do not need any lift from the middle of the skiff forward. You will have to use trim tabs to get the bow down so why have these lifting  strakes there? In a solid glass bottom they do add some strength but at the cost of being wet.


  Station # 1
Starting at the stern going forward my latest ideas on my bottom lifting - keel strake .
The added keel drawn could be added to the HBBWs Guide and 17.8 and others as they have enough vee to the bottom that will allow these mini keels to not drag.


Station # 2 


Station # 3 
I feel by softening the inner chine it will keep the water flowing closer to the hull and that will  
Get it to be directed downward and lower. Do this starting at the helmsman seat. Aft you need sharp edges to get speed and planning ability. All the spray there is going away from you. 


Station # 4 


A free hand sketch of how this really round transom will work. The bottom stern edge is straight but all above is really very round and soft. I do not like trim tab pockets as too much work . These reverse outty Pockets will be easy for installation as they can fit all kinds of trim tabs and sizes. 


Lots of lines , and angles here. Hope you can see whats happening here.

 
In reality its all very simple but on paper its a lot of lines. To remove the boat hull from the mold you will pull the hull out like taking off a shoe. The only thing is the stern sheer flange downturn will not be there to stop the hull. This is no big deal as it will be under the deck flange.

Hope this helps in thinking of different ways of getting rid that damn spray and making for a quiet stern for the purists out there.
 
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