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Progress on Terrapin - Tramps


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We are still frozen here in the North.   The creek is still locked with 6 inches of (thankfully) rotting ice.   BUT we had two beautiful days this weekend and managed to get some work done on the cat.

 

The rebuilt engine pod is installed and the newly sewn tramps are laced.

 

Question:  What do you guys think about lacing tension?  On my Hobie, tension has always been the key to a stiff boat.   But my gut says that having the tramps real tight on this boat may lead to premature tramp failure.   Less tension may distribute the load among more lacing points and reduce catenary forces.   What does your BIG TRAMP experience say?

 

You can see in the second picture that the grommets are heavily loaded from the weight of the photographer.

 

I intend to replace the forward and aft center lacing with black shockcord to try and distribute the load across more lacing points.  I will also add about 10 grommets to the center aft lacing area (5 on each side.

 

Otherwise delighted.   Maybe about 5 more hours of work, and she will be ready to launch.

 

Material:  Black Poly mesh, Shelterite borders and Gore Tenara thread (all from SailRite).  Lacing at motor pod is 3mm Amsteel Dyneema.

 

0HRKH4y.jpg

 

mMy1twq.jpg

 

My 17 year old took charge of the lacing...

 

S9cJTSN.jpg

 

And yeah - It's been a cold winter here in Maryland:

 

yUhCqg8.jpg

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Hi Martin,,   As interest, the grommets are mounted through a layer of poly mesh and two layers of Shelterite.  There is a piece of rope sewn in the edge as well.

 

Thanks for the link

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This stuff?

http://shelterritetarps.com/prodspec.html

Which weight?

 

How is it attached to the poly mesh?

 

Here is a photo showing how I used a similar material combination on my old trampolines.

trampolinmått_121026_78.jpg

 

The new ones are built differently. I have no good photo of the reinforcements but instead of grommets there are webbing hoops sewn to a wide piece of heavy polyester sail cloth. This is then sewn onto the poly mesh. You see the stitching in this photo:

ny_trampolin_2013_7.jpg

(I have changed the lacing scheme since)

 

/Martin

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This stuff?

http://shelterritetarps.com/prodspec.html

Which weight?

 

How is it attached to the poly mesh?

 

Here is a photo showing how I used a similar material combination on my old trampolines.

attachicon.giftrampolinmått_121026_78.jpg

 

The new ones are built differently. I have no good photo of the reinforcements but instead of grommets there are webbing hoops sewn to a wide piece of heavy polyester sail cloth. This is then sewn onto the poly mesh. You see the stitching in this photo:

attachicon.gifny_trampolin_2013_7.jpg

(I have changed the lacing scheme since)

 

/Martin

Thanks for taking the time to post pics.   If at some point in the future you could post a picture of: " webbing hoops sewn to a wide piece of heavy polyester sail cloth.", I would be indebted.   I have a feeling that perfecting tramps on Terrapin will be a long process.   At the moment, I'm game.  After 3 or 4 iterations of reeving and removing and reinstalling..., we shall see! :wtf: 

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it seems lashing, through tramp slots, to pvc pipe sewn into the tramp edge

 

distributes loads better, much reduced point loading problems, than grommet systems 

 

maybe next time

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while we're on the subject of tramps - lashings etc. - what's the view on individual lashings vs a continuous lashing line down each side (or indeed around the whole perimeter).

Currently my tramps are individually lashed.

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& imho

 

If it is on a boat that gets regulary dismantled, tramps taken off - then a continous line is best as it is quicker. But prone to chafe & hard to get tight.

 

If you do not plan on pulling boat apart then single lashing are better but take a long time. & you can get really tight if you spend time & will last longer as there is no movment.

 

Cheers

 

Shane

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Gentlemen,

 

My only regret is that I did not discover your forum sooner, since I have already built and installed my tramps.  I suspect I will be removing them halfway through the season to sew in a sleeve along the engine pod sides.  

 

I solicited information elsewhere on the internet, but in retrospect, it makes sense that you guys, who have been sailing things with tramps for 50 years, would be the keepers of the knowledge.  In the US, 99% of the tramp experience is with our Hobie Cats, the lessons from which only partly apply on bigger multis....

 

I humbly thank each of you who responded...

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Really Nice work there Martin!   I'm betting you have some UV protection most of the time.

 

 

Here in the US, my tramps are exposed to UV year-round.   On the advice of the previous owner, I used Gore Tenara thread on the tramp re-sew.  Pricey, but it is said to outlive the material....

 

 

Webbing-loops sewn to stout sail-cloth:

attachicon.gifny_trampolin_2013_9.jpg

Poly-mesh is folded around the tramp edges before the sail-cloth is sewn onto it.

 

/Martin

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Our sailing season is roughly 5 months long and the rest of the year my boat sits dismantled on its trailer and under a tarp. Trampolines stuffed into the port hull and sails into the starboard hull.

 

/Martin

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Thanks Again Martin and everyone for the advice.  

 

I have since removed many of my grommets and inserted an 8mm fiberglass rod along the edge of the tramp.   It is somewhat flexible, but definitely helps distribute the load across many points.  My hope is that this will get me through the season, after which I will remove the tramps and completely resew the edge with more rows of stitching and perhaps including a PVC pipe rather than the fiberglass rod..

 

At any rate, it is far better now, with minimized stress points.   More importantly it has a much more predictable tramp response which is nice when you are maneuvering about.

 

sJNKtky.jpg

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