Building a D5

[AntarcticPilot]

Dear All,

I have just started to build a D5 dinghy. So far so good! I expect it will take a while to build; I will need to take it easy as I learn new skills. So far, I've marked out the frames on the wood, using the old principle of measure twice, cut once!

There are a couple of design issues that I'd like to ask for suggestions about:

1. I intend to tow this dinghy; it's too big to carry on deck under way. What is the best way of arranging the fastenings for a towing bridle? The major constraint is that the dinghy might flood while towing, putting a large strain on the towing attachments
   • I'm unhappy about putting eye-bolts through the bow transom - that seems too weak, putting unnecessary strain on the joint between bow transom and skin.
   • I've considered putting stainless steel strip with an eye in it between the rubbing strake and the hull. Concern there is a permanent, rather sharp-edged protrusion on either side at the bow.
   • Alternatively, how about making a couple of holes between rubbing strake and hull and using them to fasten a rope bridle?
2. The dinghy will be landing on Scottish beaches, replete with rocks and mussels! Besides covering the bottom with glass-fibre/epoxy, is it a good idea to put additional rubbing strakes on the bottom? A metal strip along the keel sounds like a good idea.

 

[Grajan]

Built dozens of them when I ran a boatbuilding class and still have the paper templates! watch the bow panel, as on the D4 the template didnt match up and we had to cut a new template. Bags of strength in bow panel for towing eye providing you fit a large enough backing pad. Building the hull could be achieved by "newbies" in a few days it was the finishing that took the time as with any boatbuilding project. We experimented using both epoxy and polyester resin for laminating chines etc with Epoxy showing itself to be superior.
We always fitted a keel and four rubbing strakes, two either side, these could be either 6mm plywood about 3" wide or standard 1/2" x 3/4" hardwood rubbing stripsThey tow bow up and we never had any problems apart from accumulation of spray on the odd wild day and remember to take the oars on board!!
If I can be of any further help please PM me

 

[AntarcticPilot]

Built dozens of them when I ran a boatbuilding class and still have the paper templates! watch the bow panel, as on the D4 the template didnt match up and we had to cut a new template. Bags of strength in bow panel for towing eye providing you fit a large enough backing pad. Building the hull could be achieved by "newbies" in a few days it was the finishing that took the time as with any boatbuilding project. We experimented using both epoxy and polyester resin for laminating chines etc with Epoxy showing itself to be superior.
We always fitted a keel and four rubbing strakes, two either side, these could be either 6mm plywood about 3" wide or standard 1/2" x 3/4" hardwood rubbing stripsThey tow bow up and we never had any problems apart from accumulation of spray on the odd wild day and remember to take the oars on board!!
If I can be of any further help please PM me

Many thanks - that's exactly the sort of advice I needed. I'll certainly get in touch when/if I get into trouble!

 

[AntarcticPilot]

PS, I've heard that flooding through the centre-board case is a problem. I intend to manufacture some sort of plug, but I could imagine that coming out under unusual stresses.

 

[alahol2]

PS, I've heard that flooding through the centre-board case is a problem. I intend to manufacture some sort of plug, but I could imagine that coming out under unusual stresses.

Not on a D5 but our plug has a 'collar' made from foam tape around the top that makes a push fit into the slot. There's also a bungee that loops over the top. Never had it blow out yet and no sign of weepage.

 

[John the kiwi]

View attachment 29278View attachment 29279View attachment 29280

This is the D5 That i built as a nesting unit to go on the foredeck of my 26 ft trailer yacht.
Tows like a dream with a towing eye low on the front transom.
Also tows on the painter over the top of the transom quite happily for short distances when i am too lazy to hook up a tow rope!
It rows well and and a 3 Hp motor really makes it move with only one in the boat.
If you want details of how i made it nesting let me know.
I glassed the bottom and put a sacrificial hardwood skeg and two smaller skids on as well. So far this has stood up to being dragged up and down beaches very well.
I enjoyed making it and would quite like to build another and will again make it nesting but as a sailing dinghy.
Good luck.

 

[AntarcticPilot]

View attachment 29278View attachment 29279View attachment 29280

This is the D5 That i built as a nesting unit to go on the foredeck of my 26 ft trailer yacht.
Tows like a dream with a towing eye low on the front transom.
Also tows on the painter over the top of the transom quite happily for short distances when i am too lazy to hook up a tow rope!
It rows well and and a 3 Hp motor really makes it move with only one in the boat.
If you want details of how i made it nesting let me know.
I glassed the bottom and put a sacrificial hardwood skeg and two smaller skids on as well. So far this has stood up to being dragged up and down beaches very well.
I enjoyed making it and would quite like to build another and will again make it nesting but as a sailing dinghy.
Good luck.

Dear john,

That looks great! I guess you duplicated the midships bulk-head, and cut her in half after constructing the hull? Then installed locating pegs and thumbscrews?

I think I'll leave out the nesting idea; I have enough space to store a full-length D5 on the foredeck (I have a Moody 31), but not enough to have it on deck while under-way. Your suggestions about the skeg and other skids are just what I need.

I intend to make the sailing version, though I may not build the foil and rudder immediately. But as long as I make the centre-board case and mast-step, I can complete the job whenever it is convenient.

 

[srm]

Dear All,

The major constraint is that the dinghy might flood while towing, putting a large strain on the towing attachments
[/LIST]

I much prefer a rigid dinghy to a deflatable and have used them for most of my cruising over the last 35 years; however, I would seriously suggest that you look at ways to carry the dinghy on deck, at least in adverse weather.

Personal experience has shown that a swamped and capsized 8 ft dinghy in rough seas acts as a very effective drogue, seriously slowing the boat and in our case reducing maneuverability to the extent that we were only able to sail down wind. As there were cliffs in that direction I decided to cast the dinghy off.

I have also noticed a speed loss of up to 0.5 knot in good conditions - quite acceptable for day sailing but it may become significant when making 24 hour or longer passages.

All the best with the build.

 

[AntarcticPilot]

I much prefer a rigid dinghy to a deflatable and have used them for most of my cruising over the last 35 years; however, I would seriously suggest that you look at ways to carry the dinghy on deck, at least in adverse weather.

Personal experience has shown that a swamped and capsized 8 ft dinghy in rough seas acts as a very effective drogue, seriously slowing the boat and in our case reducing maneuverability to the extent that we were only able to sail down wind. As there were cliffs in that direction I decided to cast the dinghy off.

I have also noticed a speed loss of up to 0.5 knot in good conditions - quite acceptable for day sailing but it may become significant when making 24 hour or longer passages.

All the best with the build.

Sadly, there simply isn't clear space sufficient for a dinghy on deck routinely. The space between mast and fore-stay is broken by a baby-stay, and although there is space between the baby-stay and the fore-stay, it would probably snag the jib. It might work to put is awart-ships between mast and baby-stay, but that would probably block the side-decks and certainly the working area at the mast. I intend to store the dinghy upside-down on the fore-deck while the boat is not in use, though, so if the weather became that bad, then we'd probably have to put it there. After all, if the weather was that bad, the jib would probably either be furled or reefed, taking the foot higher above the fore-deck.

Our sailing is primarily day sailing from shelter to shelter, so we can usually (though not always) choose our weather.

 

[John the kiwi]

Nesting D5

Dear john,

That looks great! I guess you duplicated the midships bulk-head, and cut her in half after constructing the hull? Then installed locating pegs and thumbscrews?

I think I'll leave out the nesting idea; I have enough space to store a full-length D5 on the foredeck (I have a Moody 31), but not enough to have it on deck while under-way. Your suggestions about the skeg and other skids are just what I need.

I understand the problem, but just to complete the picture:
Yes, i made two bulkheads and spaced them apart with some small bits of wood so that the gap was the thickness of my handsaw. I made the boat shell out of 4 mm ply. Otherwise as per plans but I did the the internal joints first, then i cut the boat in half.
The nested length is 1300 mm.
I join the two halves with 3 x 12 mm bolts which are welded to a 50 mm x 50 mm flat washer which is screwed and glued to the bulkhead. On the mating bulkhead i have flat washers also screwed on. I use knurled hand-nuts to join it up.
In practice I launch the two halves off the bow by dropping them in and then climb down into the stern section and pull the bow section to it and join it up in the water. This is very easy to do.
I can sail my boat and still work the foredeck with the dinghy aboard, but I do leave it ashore for racing.
Good luck.

 

[AntarcticPilot]

Progress report 1

Yesterday, we marked out the skin panels on the 6mm plywood. Not quite confident of the result; I need to re-check the length of the chine seam, which at the moment appears to be different between the two panels, by about 2cm. My naive view is that this should be the same length on both panels. However, I measured it with a potentially stretchy bit of string, so it could be the measurement that is wrong. I'll step it out with dividers next. I've checked and re-checked all the station point measurements, so I don't think that's wrong.

I plan on cutting the two panels at once, to ensure the two sides are absolutely identical. Any tips or suggestions how to ensure the panels are held together during the cutting? Are spring clamps round the edge sufficient, or would a few short screws through the waste wood be better?

There's no rush at the moment - the weather in East Anglia is far too cold for epoxy to harden! Heating the garage is not an option; it is bad enough raising the temperature so it is warm enough to work while wearing thick jackets; getting and keeping the garage to +10 C (or preferably more) isn't going to happen until the weather gets warmer.

PS, Of course, the traditional method of holding the panels together prior to applying epoxy is with copper wire or (better) cable-ties. However, I have also read that Duck tape works pretty well. Has anyone any comments about what works? Duck tape is attractive because it removes the need for drilling holes and would provide a better looking finish. I have considered the idea of using cable-ties at critical points (corners of panels, for example), and Duck tape elsewhere.

 

[John the kiwi]

When i did mine i had the old D4 plans which i drew out on cad then printed on light A4 card which would feed through my ordinary inkjet printer. I then assembled the models with sellotape. I used this to sort out the practicalities o f making it nesting.
However i then found that the D5 plans had become available on a rather nice metric download and that is what i used for my full size build. I found the same 20 mm discrepancy between side and bottom. I cant remember which was longer, but since i had already cut my panels the correction could only be done one way! I trimmed the longer panel to suit and it all worked out fine. Simply meant the rake of the front transom was a little more than it should have been but i wont tell if you dont.
I used cable ties but would use duck tape and as small amount of fine copper wire as needed to hold the structure together if doing it again.

 

[AntarcticPilot]

Dear John,

Sounds like you worked through exactly the same process as I am going through! It's the bottom that is longer. Having discovered it, I may try and correct it; if I make the side 20mm longer, that should work. However, it is clear there will be a certain amount of fettling to do on assembly.

I like the idea of using Duck tape as much as possible; as well as holding the panels together, it fills the gaps, so it should be easier to apply the fillet. I'll post here on how I get on!

Too cold to work in the garage at the moment; we are having a cold-snap in the east of England, and my garage is about at freezing point!

Many thanks

When i did mine i had the old D4 plans which i drew out on cad then printed on light A4 card which would feed through my ordinary inkjet printer. I then assembled the models with sellotape. I used this to sort out the practicalities o f making it nesting.
However i then found that the D5 plans had become available on a rather nice metric download and that is what i used for my full size build. I found the same 20 mm discrepancy between side and bottom. I cant remember which was longer, but since i had already cut my panels the correction could only be done one way! I trimmed the longer panel to suit and it all worked out fine. Simply meant the rake of the front transom was a little more than it should have been but i wont tell if you dont.
I used cable ties but would use duck tape and as small amount of fine copper wire as needed to hold the structure together if doing it again.

 

[AntarcticPilot]

Update!

Thanks to all the help posted here, I've progressed to the next stage. We finished marking out the sides, and yesterday and today I've cut out the frames and sides. So far, so good! It all looks reasonably OK, though there are a few wobbles from my lack of skill! Next step will be to start assembly; the instructions with the plan seem fairly straightforward; I bet I manage to find some problems when I start, though!

A little later I'll need to lash up a stand, and to that end I've kept the off-cuts from cutting the frames out (which of course, have the correct angle to match the bottom of the hull), and intend to use them to make a temporary stand. Any suggestions or tips? I have some oddments of battens and so on around; what I had in mind was simply nailing the frame offcuts to a batten to make a couple of stands.

Hopefully I'll make more progress this week!

 

[AntarcticPilot]

OK, I've done the initial assembly. No epoxy yet - just a few cable-ties. But it's looking OK so far; it looks like a boat! I need to ensure the frames are in the right position and square to the keel next.

It is square - I checked the diagonals - but the photo makes it look a bit crooked, and some of the frames may not be quite square on.

I should say that I've never tried something like this before, and my woodworking skills are minimal!

 

[AntarcticPilot]

Just to say that things are on hold at the moment - I've taken delivery of epoxy etc. but the weather is far too cold to be doing epoxy work. The forecast doesn't look like getting warmer until mid-April!

 

[Halo]

That nesting unit looks great. Can you put SWMBO in the other half and cast her off for a while ?

 

[LittleSister]

I see you're building the deluxe version - with wheels!

Well done, and good luck with the project.

 

[alahol2]

View attachment 29278View attachment 29279View attachment 29280

This is the D5 That i built as a nesting unit to go on the foredeck of my 26 ft trailer yacht.
If you want details of how i made it nesting let me know.

It would be very good to have it on record here if you are able. I may well need something similar in the not too distant future. Even better if you can do it with the sailing version.

 

[AntarcticPilot]

Masts

Dear All,

No further progress to report - still too cold for epoxy, though I hope it will be Ok soon.

I've started to think about the spars. I want to build the spritsail rig, and the plans suggest 54 mm diameter spruce as the material for the spars. I find that this is difficult to obtain in the right size locally (smaller sizes are available, but not the 54mm), and silly prices if I have to get it delivered! It seems to me that I ought to be able to substitute alloy tubing, or perhaps other GRP or other composite tubing, with perhaps wooden end-caps. But I have no idea what diameter and wall thickness of tubing I'd need to match the characteristics of the spruce that is recommended on the plans. Can anyone help with this? I need to know the diameter of the mast at this stage so I can build the mast step before fitting the mast partners/forward seat.

Thanks!