7ft pram mast & sail?

[aztec]

well iv'e gone and done it... put the pram dingy back together, theres a slot in the keel once more, and there's a hole where a mast should go...

thing is, what size mast? is there a ratio between length and mastheight? also what is the simplest rig (only want to mess about.. rather than bolt an engine on the back)... and let the kids have a play.

i know nothing about sails (another thing i can add to my list of things i know now't about) and even wondered about an old board sail?

if i dont stick a rag on it, i'll only use it as a tender with an old seagull on it, so any info greatly appreciated.

thanx, steve.

<hr width=100% size=1>

 

[Rich_F]

Changing the subject a bit (sorry), but is this a currently available pram you've been reassembling? I'm thinking that a 7ft pram with a sail would make a fun tender - has anyone got any recommendations? A home build might be a fun winter project

I've gone off inflatables due to laziness - I tend not to go ashore at anchorages because of the hassle of unstowing, inflating, deflating and re-stowing the dinghy. A little tender to stow on deck would solve the problem.

Rich

<hr width=100% size=1>

 

[Jacket]

35 square feet of sail would be typical. If you fitted a standing lugsail, the spars would be short enough to stow inside the dinghy.

<hr width=100% size=1>

 

[Guest]

There\'s an old saying ...

If it looks right it probably is right.

You could go the light simple way and a single larger mainsail rigged further forward...... you could go the dipping lug style ---- still single sail ......... you could get some Mirrpor dinghy stuff ?? but that would probably be a bit on the larger size for kids to lark about with ....

You really wouldn't want to have a mast that is overl,ong on the boat ---- trailering etc. - so a length of about 9 -10 ft would most likely be about it.

In fact taking the simple rigs idea ..... a Windsurfer set-up might not be such a bad idea ...... you could even rig a forestay ! with a small handerkerchief of material as a jib !!!!

Tiller ...... cut a slot and use an old oar !


<hr width=100% size=1>Nigel ...
Bilge Keelers get up further ! I only came - cos they said there was FREE Guinness !

 

[sailorbaz]

I have a 7 ft pram plastic moulded shell which has needed fitting out for the past 10 years, I have promised SWMBO that I really will do it this Winter!
In anticipation of finishing the project I made a Gunter rig. The mast is dinghy extruded section 215 cm long. I had a plate with a square block welded to the foot and after cutting away the track at the top to fit a pulley, I had a plate welded on top. The boom and the gaff, both 190 cm long, are genoa roller reefing sections - the sort with only one groove. If you make the rig with these lengths, the whole rig complete with sail can be rolled up and stowed inside the dinghy. I have a very old Dacron sail which I intend cutting to fit and stitching plastic sailslides on the luff.
Hope this helps.
Sailorbaz

<hr width=100% size=1>

 

[richardandtracy]

I've been using a 2" x 2" planed all round (par) softwood mast, 6ft long. The boom and yard are both 2 off 2" x 1" par softwood, about 10ft long. The sail's cut from a cheap green tarp & is trapped between the boom & yard timbers. The two halves of the boom and yard are screwed together through the sail after wrapping a loop of sail around one side. Sail area is about 36ft^2 on an 8ft dingy (inspired by the Bolger 'Brick' - http://www.instantboats.com/brick.htm).

Haven't broken anything yet (just been using it this year), but there again I don't tend to try going all out.

Regards

Richard.


<hr width=100% size=1>

 

[aztec]

hi, i'll answer the easy ones first!!

this is an old moulded grp dingy, like a pram/mirror shape. i had to mend it as it was split up the sides and needed the inside and outside mouldings separating to re-glass the floor and sides... it's now very strong!!. i only got it so that i could leave it on the bank to get to my boat.. but 'cos it had all the stuff for a sail i thought it'd be fun to try to sail it.

but yes it'd make a fine tender. i will take sizes from it and build another lighter one out of ply to carry on my old osborne and the tender. the grp one (painted light green) would'nt quite look right!

regards, steve.

<hr width=100% size=1>

 

[aztec]

thanks for the replies, i have a general idea what you mean. but, iv'e got to be honest when i say i know nothing about sails... i don't!!

sails are triangular?
pole in the middle is the mast?
i think i know what a boom is... the bottom bit?
as for rig type... um?

(i might just stick an engine on it untill i know what i'm doing)

PS what is Gaff?

sorry to take your time... i need to go look in some books now.... steve.


<hr width=100% size=1>

 

[qsiv]

I'd make all three spars about 6" shorter than the boat. Mast will need a sheave at the top (couild be a block tied there). Rig it as a standing lug, allowing boom to be about 6 to 9" Fwd of mast, with a simple line to pull it down - doesnt need to be attached to mast as such. Gaff will protrude same amount fwd (which might mean about 9 to 12" of spar protruding because of angle). Experiment with lashing poiunt for halyard on gaff. Hoist gaff to masthead, and make halyard fast, either to stem or to mast below boom, or to thwart mast is probably stepped through (this prevents rig falling out when sailing). Apply tension to boom downhaul. Ennsure sail is cut so that boom clears your head when sailing/ kneeling in dinghy. Mainsheet is unlikely to need to be more than a single part line attached to boom. If you need a little assistance on sheet, then fit a pair of pins under each of the rear quarter knees, and loop sheet around to add friction.
Oh and mast size - I'd say about the same as the oar looms.

<hr width=100% size=1>

 

[aztec]

that sounds like my sort of engineering. how does the sail attatch to the mast/boat? and how do you fix the mast, i think the front one is the forestay... and if i use two backstays would that do it?

i can't see how the boom attatches to the mast... does it? and how do you raise the sail?

this could possibly be the last question, as the more i look into it... the more i realise that i have'nt a bleedin' clue!!

cheers, steve.

<hr width=100% size=1>

 

[penfold]

Sounds like what would be quickest if not the cheapest would be to get an Optimist dinghy rig; that is a gunter type thing and an Optimist is about 7ft long.

cheers,
david

<hr width=100% size=1>What in the wide, wide world of sports is goin' on here?

 

[VicS]

Yes I was going to suggest copying the Optimist rig.

It's not a gunter rig though, that has a gaff that hoists vertically in effect extending the luff way above the height of the mast but using spars which will (just) stow in the length of the boat, like a Mirror . The Oppie rig is called a "balanced lug" (I'm sure you will find some pictures on the Optimist website) but it does need mast boom and yard.

Alternatively make a two part mast from two slightly different sizes of aluminium tube and a simple triangular sail, with a bit of roach, which is sleeved over the mast like a Topper. About 2.5m by 1.8m should be about right for a 7ft dinghy. You could make it loose footed, in which case the foot will have to be reduced, and avoid the need for a boom and make the leach slightly hollow rather than with a roach thereby avoiding the necessity of battens. In either of these cases the dimensions of the sail will have to be adjusted to maintain roughly the same area.

You do need to consider the relative positions of the cenre of effort of the sail and the cenre of lateral resistance of the centreboard to ensure that the final product has a small amount of weather helm. If you get the former in front of the latter you will end up with lee helm which you definitely don't want.

What I have described is based on the sail plan of my Puffin (remember the one with the collapsible sides). In a bit of a breeze it goes like a train with 12½ stones on board.

It's not quite a question of sticking a bit of rag on a stick as all stinkies believe!

P.S. Just gone back and read your 17:24 post.

Re suporting the mast: locate the heel in a block of wood in the bottom of the boat and arrange a support about 15 inches higher to avoid any shrouds etc. but arrange a means of preventing the mast from jumping out. Re attaching the sail: sleeve the luff as suggested and arrange a down haul to hold the sail on the mast (from the underside of the boom) attach the sail at tack and clew corners to the boom. Re attaching the boom to the mast: make the boom with a crutch to fit against the mast then with the sleeved luff nothing further is needed. (look at a Topper)

<hr width=100% size=1><font color=purple>Ne te confundant illegitimi.</font color=purple><P ID="edit"><FONT SIZE=-1>Edited by VicS on 17/09/2003 21:03 (server time).</FONT></P>

 

[spark]

I have a 7ft clinker pram that I built 20 years ago as a tender. Some time later I put a dagger board into it and rigged it with a sprit sail.

Mast (a wooden pole about 1-1/2" diameter) same length as boat, stepped well forward, through hole in forward thwart unstayed.
Sprit (wooden stick about 1" x 1-1/2") same length as mast.
Quadrilateral sail: short diagonal = clew to masthead; long diagonal = tack to top of sprit.
Sail permanently rigged attached to top of mast (i.e. no halyard) and sprit.
Sprit permanently attached to mast just above partners with a line (called a snotter).
Single part mainsheet to hand.
Rigging the boat is as simple as dropping the mast into its step unfurling the sail and off you go.
When it's time to stop simply push the sprit up against the mast and tie it in place with the sheet.

The sail is cut from a plastic tarp but I've heard that Tyvek building paper is even better.

I also avoided the compelxity of a rudder by steering with an oar which is captive in a rowlock which is mounted in a socket on the transom. I only had one socket in the middle of the transom but I'd recommend one either side of middle for each tack.



<hr width=100% size=1><A target="_blank" HREF=http://www.qei.co.uk/spark>http://www.qei.co.uk/spark</A>

 

[joeh]

Re: There\'s an old saying ...

what abt centreboard ? a movable one for each side?

<hr width=100% size=1>

 

[aztec]

Re: There\'s an old saying ...

it's got one, well a box for one. i'll make one this afternoon.

and a new rudder. thanks all for your help.. nigel has given me the basis to start with... nice and simple. so i'll see how it goes. maybe once iv'e hjad a go i'll try a more complicated (for me!) set up.

you never know i might like it.. quite looking forward to exploring the tributories (sp) off of Poole harbour, which i cant do in a larger boat.

thanks again for all of your help.

steve.

<hr width=100% size=1>

 

[burgundyben]

A gaff.

Steve, a Gaff is when you say something you really should not, and are overheard by someone you really dont want to overhear, like saying quietly (when drunk) "christ, look at the size of her arse" - then subject turns round and says something like "well really, how rude young man!" - thats a a gaff, made many of them myself.

<hr width=100% size=1>Sod the Healey - I think I'll buy an E-Type.

 

[richardandtracy]

Mast.
First I should say the mast is on the starboard side of the dingy. It's the way the Bolger Brick/Tortoise is. [same with the dagger board too].
I've got 3 steel straps that go around the mast, one at the top of the boat (gunwale), one at the floor (keel) and one midway where it goes next to a seat (thwart). The steel straps are all 25mm x 2mm bent to go around the mast - because that's what was in the steel scrap skip at work on the day I looked.

The mast slots in to the holes, and if I'm feeling paranoid on the day I put a loop of 6mm polypropelene from one of the 4 cleats on the mast around the metalwork to stop the mast jumping up and out of its socket. I frequently don't bother if the winds are light.
I put 4 home made steel cleats just above the gunwale (25 x 2mm flat & 6mm dia bar).

Next..
Forestay/ backstay etc. I don't bother with them. The mast's too short to need any.

How's the sail attached to the mast?
I made up a steel loop that's screwed to the middle of the top of the yard (wood bit at the top of the sail) and put a 6mm polypropylene rope from there to a sheave at the top of the mast. The rope then goes down to the cleats on the mast just above the gunwale. Initially I had just a steel loop at the top of the mast, but the friction was too high.
The yard is attached to the mast with a loop of 6mm polyprop rope. The rope is knotted, passed through a hole in the yard, around the mast and back though another hole about a foot away where it's knotted.
At the bottom of the sail, the wood bit (boom) has 3 steel loops.
One at the front has a loop of rope going around the mast to stop the boom going too far forwards. One at the designed mast position (about 1/6 boom length aft) ties the boom to the mast with a second loop of rope.
The final steel loop on the boom is about 5/6 of the boom length aft. This is where the sheet ties to (used to alter the sail angle to the wind). The sheet loops through a sheave on the stern (once again, I originally had a steel loop which gave too much friction).

That's it.

Nothing fancy.

All the steel was scrap, welded up as necessary. I was - despite the pain in my wallet - forced to buy the timber and rope new. I bought a 25m hank of 6mm PP rope, which was plenty. Sail conversion cost £20, which was £7 above budget (due to my original sail [tarpaulin] becoming unavailable between compiling the budget & buying it). Oh well.

If you want a DXF/ AutoCAD drawing of the whole dingy, PM me with your e-mail address and I'll send you a copy. The drawing doesn't show the ropes well, but I think it would be OK - and doesn't show the [few] changes since I built it.

Regards

Richard.


<hr width=100% size=1>

 

[aztec]

Re: A gaff.

i'm sure then, i'll have no trouble at all making one.... in actual fact there must be some old one knocking about round here!

d'you know anything about a Brooklyn's Aviation 16ft cabin cruiser C1955? been to have a look at one today.. very pretty little boat, and in amazing condition.

best wishes, steve.

<hr width=100% size=1>

 

[Trevethan]

if you don#'t fancy the woodworking, the rig from an optimist would probably do the job.

cheers

<hr width=100% size=1>