Dart 15 Forums

Hello all,

I bought my Sprint last fall and I am preparing it for the season.
My trampoline has been locally fabricated with the warp parallel to the hulls thus tightening the trampoline doesn't pull the hulls together.
I have about a 6 to 7mm play between the hulls and the rear beam clips. I loosened the 10mm nuts and tried to adjust the clips back against the hulls but they wouldn't move back in.
Is that kind of play too much? In that case I could install a packing piece between the clips and the hulls. Or should I not worry about the play?
Thanks for your insight,

Cheers, Thierry

Hello Thierry,

did you thoroughly tighten the tramp? You can use piece of strong wood like an axe or hammer handle to lever the string tight. It should be like a guitar string.

If you have done that and the boat is still moving about you definitely want to pad it to make the hulls parallel and rigid.

Thanks Liam

Hello Thierry

As Liam says, you want the tramp to be almost like a drum skin and when it's tight the plastic attachments in the rear beam will be pulled downwards. I use a piece of approx 50mm x 20mm x 500mm wood with a pair of mole grips to pinch the dyneema (get rid of the original string and use some pre-stretched ~5mm dia) at each eyelet before tightening upstream.

Thoroughly wet the tramp first and carefully jump up and down on it to stretch it. You will not get it fully tight first go, so do it a few times until you're happy.

The acid test is to lift one bow off the ground (boat flat on the ground, not on the trolley) & the other should move with it - any delay in the second bow moving and your boat is not rigid.

Some folks have had to chock the beam stops - not me personally, so maybe make some measurements off the stop outer edges & check with Windsport the dimension +/- tolerance.

You do right to get this fundamental element of the boat correct before sailing as a loose boat will wear itself out with the slack fits and it will not want to go upwind or through waves without distorting.

What age is your boat as the tramp 'bolt ropes' & hull tracks either side changed around 1930 ish (sail number that is!) as they were notorious for pulling out of the track, so if you have a bit of pull out at the forward most edge of the track that is sort of normal. Careful with the old tracks as if you do all the above you could pull the old rivets out, so just something to be aware of.

Unrelated to the tramp, do be sure to pin your mast ball/mast when your boat is in the boat park to prevent wearing them both out while you're not sailing!

Thierry

If I read your original post properly I can see that actually your locally made tramp may well cause you boat issues in both setup and sailing.

To be honest I'd get the proper one that the boat is deigned for and save yourself a whole load of grief too (also prevent damaging the boat) & then my set up process would be relevant.

Cheers

Mark

Agreed. The diagonal cut of the tramp is essential to pull the hulls together. Sorry, but I reckon you need a properly made trampoline...
How about advertising for a second hand trampoline by putting a wanted advert on this website if cash is short?
Regards
Bob

My first boat had a trampoline cut like yours and I managed to get the boat rigid enough by looping rope around the backs of the hulls and pulling very tight before tightening the tramp string.

It went across the Channel twice without falling apart. It can be done. It just needs a bit of effort.

If you do get a new tramp, I would recommend getting a large bolt rope tramp and the new bits that join it to the hulls as well - rather than buying the old style small bolt rope trampoline that would fit your boat. The new attachments are way better.

Thanks Mark, Bob and Liam for the replies with tips.

I have packed the gaps between hulls and clips with aluminum plates after having checked that the hulls were parallel.

Buying a new tramp is not in the cards right now as I have to test the boat in the water first.

Liam, I read your account about crossing to Alderney and back and the other trips too. I love that stuff.

I have well understood that the tramp is key to stiffen the boat and will try my best to get it as stiff as possible.

The boat is #1571 so with the small bolt rope.

And thanks Mark for the tip about locking the mast and the ball while on land.

Cheers, Thierry