Modernizing a Prout Elite 37ft

[atoll]

Originally Posted by Snowgoose35

Hi Alex, slight drift but was hoping for some advice. I'm also making an Iroko rubbing stake to replace the rubber U channel someone put on year ago which has seem better days.

I don't want to screw it in to the hull to deck joint though and was wondering if there's any good reason not to fix with Sika (with Sika primer first so it really sticks) or even West System epoxy as I have a big tin left over... Any advice please?

hi,i'm assuming you are referring to sticking the new iroko rubbing strake to the hull,not rubber "D" section.

to answer your question,yes both sika flex or epoxy would work as adhesive though with epoxy it would be advisable to remove the gelcoat where wood meets fiberglass.

also bear in mind that there is still a degree of flexibility in the hulls which might cause the epoxy joint to crack and fail over time,so for this reason a polyeurathane sealant/adhesive like sikaflex291 ,(I used puraflex400 which is half the price) would be the preferred method.

your next problem is how to hold it in place whilst the adhesive cures?

I belive this would be very difficult without using either large diameter self tapping screws or through bolted, as there is a fair bend in the hulls and nowhere to use clamps to hold the strake in place.

if you could laminate your rubbing strake into" one" 33ft section you might get away with only through bolting fore and aft,inside the watertight compartments at the back and front of the hulls which are fairly accesable to a smallish person>60kg!

it is also important to get the "slot" on the inner side of the rubbing strake right to fit the outer profile of the hull/deck joint as this centralises the rubbing strake along the join when it is pulled tight and makes a fairly sung fit and inturn creates a good seal which will push out excess sealant/adhesive.

the hull joint has an outside profile like this"{",and I used the following diamentions for the rubbing strake.
outside 48mm x 31mm.wth 1/4' router radius on outer edges.

inside diamentions of rubbing strake grove for outer hulls
depth of channel,14mm,width16mm 1/4' radius on either side of the grove/channel.

for the inner hulls and crossbeams the fiberglass moulding is slightly thicker

so you will need to make the grove slightly wider

so depth of channel 14mm,width 20mm,with 1/4'radius.

hope this helps,

photo is of some off cuts I had in my bag ,but have been cut at 45 degree so not quite the above diamentions on inner edge,but a picture is worth a 1000 words

[Snowgoose35]

Thanks Atoll - that's very useful. I very much appreciate the detail.

[atoll]

Originally Posted by Snowgoose35

Thanks Atoll - that's very useful. I very much appreciate the detail.

no worries,i forgot to mention,i used 17 tubes of PU sealant/adhesive,and about 120 x 50 mm countersunk A4 M6 machine screws
at 15 inch spacings.

[Buzzman]

I'm a bit unclear as to why you bothered "sealing" when you are bolting the rail to the hull?

Is this just to protect the inner faces of the timber edging from water penetration, or some other reason?

Like the adhesive/sealant PU 40 actually holds the timber on and the bolts are only to hold it in place while the 'glue' hardens...????

Could you not (theoretically) lash the rub rail to the hull using around hull ratcheting straps and thus do away with the majority of the bolts in that case?

Or is that impossible, even on a hard stand..??

[atoll]

Originally Posted by Buzzman

I'm a bit unclear as to why you bothered "sealing" when you are bolting the rail to the hull?

Is this just to protect the inner faces of the timber edging from water penetration, or some other reason?

Like the adhesive/sealant PU 40 actually holds the timber on and the bolts are only to hold it in place while the 'glue' hardens...????

Could you not (theoretically) lash the rub rail to the hull using around hull ratcheting straps and thus do away with the majority of the bolts in that case?

Or is that impossible, even on a hard stand..??

the best example of why it is nessacary to fix the rubbing strake is that it is like a hull plank on a wooden boat.

,ie it has to bend to follow the shape of the hull,not the natural bend that the wood would like to take.
making it nessacary to "persuade" the wood,so the bend is done in stages,by bending a little,then fixing,then bending some more and fixing till you reach the other end.

I'm in the water so using the ground as you could in a hardstand is not an option.

to answer the other question of why bother sealing?
simple,because it WILL leak into the accommodation area if you don't,a bit like putting PTFE tape on a plumbing pipe joint

also, bear in mind the rubbing strake is not for decoration ,but to protect the hull from abrasion over the life of the vessel and needs to be able to withstand considerable loads,not only from the side,but up and down,shock loads,rubbing against poles,other vessels etc

this is why I belive it needs lots of fasteners,otherwise it is liable to get wrenched off the first stormy night in a marina,or 3rd world police boat bumping into you

[Buzzman]

Yeah, OK, figured that would be it, but wanted to clarify.

I've been trying to work out how to avoid doing exactly that on a dinghy I'm modifying to turn it into a 'dinghy cruiser'. Needs more freeboard and enough height on the transom to mount an outboard.

I've built up the gunnels with foam and glass 400gsm so pretty stiff, and think I'll bore and epoxy fill, then screw into the epoxy so it doesn't go thru hull, avoid leaks.

But now thinking I might Sika the gunnel strake on rather than epoxy as I was going to, so it has some flex in case of hard knocks. Dunno if I can get that PU 40 over here, but Sika is readily available.

[atoll]

Originally Posted by Buzzman

Yeah, OK, figured that would be it, but wanted to clarify.

I've been trying to work out how to avoid doing exactly that on a dinghy I'm modifying to turn it into a 'dinghy cruiser'. Needs more freeboard and enough height on the transom to mount an outboard.

I've built up the gunnels with foam and glass 400gsm so pretty stiff, and think I'll bore and epoxy fill, then screw into the epoxy so it doesn't go thru hull, avoid leaks.

But now thinking I might Sika the gunnel strake on rather than epoxy as I was going to, so it has some flex in case of hard knocks. Dunno if I can get that PU 40 over here, but Sika is readily available.

have a look around for "high modulus polyeurathane adhesive sealant"at hardware stores.
for the puraflex400 I pay £3.87 as opposed to £7.50+ for sikaflex291 which is basically the same.

another tip for unused pu,seal the nozzle with masking tape as soon as you have finished working with it and store in the fridge or freezer,will stay usable for months.
also use white spirit generously for clean up,have lots of clean small rags and a bucket for discards

[weavis]

As stated before, I have used commercial hot glue guns and commercial glue sticks to hold surfaces in place whilst the main adhesive is curing. (NOT the household hot glue sticks.)

Now, Im pretty sure the hot glue would struggle with some of the projects like the straking in lengths, but...... Ive held up some pretty heavy stuff whilst a 2 day cure was required. Its amazing stuff.

[atoll]

Originally Posted by weavis

As stated before, I have used commercial hot glue guns and commercial glue sticks to hold surfaces in place whilst the main adhesive is curing. (NOT the household hot glue sticks.)

Now, Im pretty sure the hot glue would struggle with some of the projects like the straking in lengths, but...... Ive held up some pretty heavy stuff whilst a 2 day cure was required. Its amazing stuff.

glue guns are great for building temporary moulds out of MDF in the workshop

though what I don't like is the tendancy for them drip with no way to remove excess glue without a sharp chisel,as they are impervious to solvents,unlike most other adhesives

[weavis]

Originally Posted by atoll

though what I don't like is the tendancy for them drip with no way to remove excess glue without a sharp chisel,as they are impervious to solvents,unlike most other adhesives

Yes, we all made that mistake. I usually just put a dab of the glue along the length, just enough to hold and no more! As it cools, it holds. I just made back splash units for a kitchen out of Corian and its held in place by a dab or two as the silicone cures......

[HappyMdRSailor]

Originally Posted by SaltyMonkey

SaltyMonkey approves of Atollboat. You know it's reaching the end of teh build when we're concerned about cosmettix tow-rayles instead of building a nav station.

GO ATOLL!!!!

I think we all approve SM!

This project was daunting and impressive from the start...

[boatman61]

Yes.... its always good to see the Youngsters having a go at things..

[HappyMdRSailor]

Originally Posted by boatman61

Yes.... its always good to see the Youngsters having a go at things..

HA!

[atoll]

Originally Posted by boatman61

Yes.... its always good to see the Youngsters having a go at things..

Ta gramps!
nearly 40 years now since I built my first stich and glue dinghy

[atoll]

FYI in other news I just received this from james wharram
which I will probably go to,so if anybody has any questions for james or hanneke I can pass them on

PRESS RELEASE - 60th anniversary of first offshore catamaran to set sail from Falmouth
This year on May 15th I was 87 years old.60 years ago, on the 27th September 1955, I set sail from a Falmouth quayside aboard a self-built 23’ 6” flat-bottomed double canoe (now called catamaran) called TANGAROA with two German girls as crew. My quest was to sail the Atlantic to prove the double canoe was a seaworthy vessel. In a Pathé newsreel clip filmed in Falmouth

I called myself a marine archaeologist, a profession which did not exist in 1955.The story was that in 1948 Thor Heyerdahl made the famous KONTIKI voyage across the Eastern Pacific from Peru to the Tuamotu Islands ‘proving’ he said, that the inhabitants of the central Pacific islands must have come from South America by sailing raft (not as is now accepted from SE Asia by canoe craft.)At the age of 16 during the war years I had bought a book ‘The voyage of the Kaimiloa’ written by a Frenchman, Eric De Bisschop; my first and probably most influential book in what is now an extensive boat library. De Bisschop built a 38’ junk rigged, Pacific inspired double canoe in Hawaii in 1938 and sailed it with a companion across the Pacific, Indian and Atlantic oceans (via Cape of Good Hope) to Toulon in France, thereby proving that the Pacific double canoe was a seaworthy craft, capable of making long ocean voyages. On arrival he received a heroes welcome, then in 1945 was written out of history because of WW2 and his family connection to the President of Vichy France! As a result Thor Heyerdahl was able to persuade the public with his widely acclaimed Kontiki raftt voyage that the ancestors of the Polynesians came from the south American mainland by sailing raft, because, as was then believed, the canoes of the central Pacific were not sufficiently ocean worthy for migratory voyages. This explains why I, as a disciple of Eric de Bisschop, was in Falmouth 60 years ago with a 23’6” double canoe, about to cross the Bay of Biscay and on to Las Palmas to sail across the Atlantic Ocean to Trinidad. An ambitious project to prove Thor Heyerdahl was wrong. From that voyage with a greater understanding of ocean sailing double canoes I built a 40’ v-eed hull catamaran in Trinidad (called RONGO), sailed it 1500 miles north to New York, then made the first ever multihull voyage from West to East across the stormy north Atlantic in 1959. This led me to become a designer of catamarans.In many ways life is a series of seasons that echo our beginnings and in my design life I have come full circle with a brand new design, the same length as my 23’6” TANGAROA, a light weight trailer sailer/Coastal Trek catamaran, the MANA 24. She has modern features and influences, but essentially the design philosophy that inspired me as a young man still motivates me now.Suffice to say; I think that modern sailing boats are being priced out of the market. Not just by 20% VAT but by the price of moorings and marinas. The best solution to this problem is to self-build your boat and totrail it home. The other advantage of a trailer boat is that you can take it to different sailing grounds, or to where the weather is good, giving you a much wider horizon.Last year a book called ‘Micro Adventures, local discoveries for great escapes’ by Alistair Humphreys was published. This book ties into my life philosophy as a rock climber and wanderer before I became an oceansailor. A small boat that can be trailed, like the MANA 24, can satisfy this spirit of adventure that so often never gets a chance in our hectic modern urban lives.o the practicalities: I/we assisted by a team of Cornish enthusiasts; local designer and CAD expert Simon Holman, the computer cutting firm Fibrefusion and the Cornwall Marine Network, have tied all our sailing, design and building knowledge into this new 24’ car trailer-sailer design to be sold as an easy to assemble ‘Ikea’ style kit boat using state of the art CNC machines, 3D graphics and a design concept we hope will appeal to an audience of adventurous, free spirited people. Low budget sailing, camping and adventure for families feeling the sting of the economic downturn. The plan was to have the first MANA 24 moored in Falmouth at the pier where we departed from with TANGAROA in 1955. However such is life, the boat will not be ready to launch on that date, so we plan to host a reception (incl. drinks and refreshments) in our studio/workshop in Devoran with exhibits of the voyage in 1955 as well as the MANA 24 under construction to view. This can be followed by a visit to the quay in Falmouth for a photo opportunity. We hope to be able to moor our other 27’ double canoe AMATASI at the quay.You are warmly invited to this reception, which will be held on Wednesday 30th September at 2pm at the address below. RSVPJames Wharram FRGSJames Wharram DesignsGreenbank Road, Devoran, Truro, Cornwall, TR3 6PJ, UKTel: +44 1872 864792 Personal email: james@wharram.com Office email: wharram@wharram.com Website: James Wharram Designs | Unique sailing catamarans, self-build and professional built boats of distinction.. Websites on canoe project for Tikopia and Anuta: Tikopia canoe project by Hanneke Boon. and Herzlich willkommen auf der Internetseite: Lapita-Voyage More on Mana 24: Mana 24 is becoming a reality – by James Wharram | James Wharram Designs