New Build - 24m aluminum passagemaker

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For your choice of "no paint" in the bilge after 16 year with our "Hoa" it must be tempered :
In our boat we just paint inside :
under the box of chain prier and few coat of "epoxy brai" under the toilets areas just one single coat of "primer".
After 16 years this paint still in very good shape.
For the next one may be we will paint also all fore-peak, and the bilges because the side with even only one coat of primer paint looks better than the side without paint after 16 years. Ok the Al was not damaged but it is not absolutely perfect like the painted one.
 
Merci Long-cours. Understand your approach but for us we simply don't allow any paint on any AL surface for even less maintenance and zero risk of trapping moisture between the AL and the paint or sprayed on material.

However we spend a LOT of our time in very hot climates and know the value of a super well insulated boat and will go even further on the new boat. Our previous steel boat had excellent insulation from 3-4" of sprayed on foam on all the interior surfaces other than the bilges and this worked extremely well. However there were areas that were not well foamed when it was built and caused us a great deal of trouble to replace the rusted out panels that resulted.

So for the new boat we will go with adhesive backed EPDM sheets that we will apply to almost EVERY interior AL surface including all the stringers, frames and webs. We think of it as a "Thermos bottle" type approach and works equally well in hot tropical climates as well as frozen Artcic/Antarctic locations, all of which we intend to visit.

For the decks we will glue down synthetic material such as TreadMaster to provide both a very non skid surface and one that absorbs the least amount of sun possible to keep them cooler.

Thanks again for your comments and experience,

Wayne
 
"For the decks we will glue down synthetic material such as TreadMaster .."
In my point of view Treadmaster or similar products could be worst than a paint.
Look around old boat fitted with this product, when they remove them they got big "surprises" on fibreglass boat it is not a big problem (for example on the old Fisher) but on alloy boat the surprises could be very bad ( in France from may 40 years we had some alloy sailing boat fitted with Treadmaster and the result is not good.
When we decide to keep our deck in raw alloy with good "deck shoes" it was acceptable but for the sun ....not at all. And on metal material I am not a partisan of anything (wood, treadmaster, ) always the sea water found her way and the salt and humidity stay ...for years , even on boat built carefully in very good and very expensive boatyards.
 
"For the decks we will glue down synthetic material such as TreadMaster .."
In my point of view Treadmaster or similar products could be worst than a paint.
Look around old boat fitted with this product, when they remove them they got big "surprises" on fibreglass boat it is not a big problem (for example on the old Fisher) but on alloy boat the surprises could be very bad ( in France from may 40 years we had some alloy sailing boat fitted with Treadmaster and the result is not good.
When we decide to keep our deck in raw alloy with good "deck shoes" it was acceptable but for the sun ....not at all. And on metal material I am not a partisan of anything (wood, treadmaster, ) always the sea water found her way and the salt and humidity stay ...for years , even on boat built carefully in very good and very expensive boatyards.

Merci encore. We have found and been on some boats with glued on TreadMaster type of material that are as you describe however we have been on many more with no problems. I think that as with many other components and with painting itself, it is all about the preparation and application and we believe that if this non skid material is glued down with good preparation and application it will hold up for at least 20 years with no intrusion of water. We prefer no shoes most of the time in warm/hot climates so the added thermal barrier this provides is important to us and otherwise we might consider painting on non skid surfaces.

We are a long time aways from needing to make this decision and your concerns are certainly heard and we will do more research and looking but right now we believe that when all our use case criteria are taken into account and that we will be doing the application, we think that glued down synthetic material on decks will be the best choice for us.

I spent a bit of time this morning over on your website looking over your very interesting boat. Some similar thoughts with yours and ours and looks like you've got a boat that suits you very well.

Thanks again for your very thoughtful remarks and concerns. Please keep them coming.

Salut,
Wayne
 
Thanks for your comments. A Gardner I nearly bought captivated me with its slow, (350 rpm) smooth and steady idle.

My boat is 43 years old and is in the process of being “improved.” This is the condition of my decks currently with stick-on tread. Its incredibly difficult to remove, leaves glue residue and corrosion underneath. I am trying to find somebody with a dustless sandblaster to blast the decks clean and provide a non-skid surface. I personally will never paint or glue anything on them again and have been trying to find a solution. Modern boat builders may have found the solution but so far I haven’t. I have no idea how long these treads have been on there, I’m in my 5th year of owning “Old Shiny.”

That picture of the aluminum boat I posted had been blasted all over except for a taped border around fittings and openings, leaving a shiny frame. Nice solution. He, however, painted his decks with no-skid....

My roofs have freight decks installed, essentially providing double decking which provides a very cool interior in the hot sun. Even thought the ceiling is insulated, feeling the heat come through where the double decks are not installed is remarkable. Think of a Land Rover with a tropical roof.
 

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I’m loving following this discussion of AL boats. I actually have really liked the looks of the aluminum pleasure boats that I’ve seen. The bare, oxidized metal doesn’t put me off at all.

I do have a question though. Insulation has been mentioned, but I don’t understand how glueing insulated panels to the inside is going to avoid the potential problems of moisture getting between the panels and the AL causing corrosion issues?
 
Good morning, there are no corrosion issues when there is no water present. I scraped a lot of foam out of my bilges (it had been extensively done by the PO too) and there was some corrosion under it, fortunately contained to a bulkhead and not the hull! In the walls and ceiling, very dry and zero corrosion. I have a photo of ruined aluminum somewhere which I will post if I can find it.

One other consideration that is probably familiar with a steel boat, Make sure you isolate all fasteners that attach to the aluminum structure; I'm not describing this very well but for example if you attach panelling to a wall, use firring strips attached to the aluminum and then screw to the wood, never screw into the metal as the warm air touching the screw head will rain condensation from the cold screw head, rusting the fastener and staining the panelling and everything the moisture drips on. A PO attached a radio to the ceiling of the wheelhouse and the metal bracket dripped like a tap.
 
The aluminum is a piece of my engine room bulkhead, cut out with a sawzall. The upper edge was down...The ceiling shot is NOT a leak but exposed fasteners. I completely stripped the room, insulated, firring strips new ply new everything. Do you like the panelling? Early Atco Trailer. Scary for anyone who has ever lived in a bunkhouse!
 

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This is how I heat the inside, these are "towel heaters" and they are amazing. Silent (no more of those rotten bus heaters) and radiate like a fireplace. The head can get like a sauna, great when having a shower or...Powered with a Hurricane boiler which is now the noisiest part of the heating system.
 

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Thanks for your comments. A Gardner I nearly bought captivated me with its slow, (350 rpm) smooth and steady idle.

My boat is 43 years old and is in the process of being “improved.” This is the condition of my decks currently with stick-on tread. Its incredibly difficult to remove, leaves glue residue and corrosion underneath. I am trying to find somebody with a dustless sandblaster to blast the decks clean and provide a non-skid surface. I personally will never paint or glue anything on them again and have been trying to find a solution. Modern boat builders may have found the solution but so far I haven’t. I have no idea how long these treads have been on there, I’m in my 5th year of owning “Old Shiny.”

That picture of the aluminum boat I posted had been blasted all over except for a taped border around fittings and openings, leaving a shiny frame. Nice solution. He, however, painted his decks with no-skid....

My roofs have freight decks installed, essentially providing double decking which provides a very cool interior in the hot sun. Even thought the ceiling is insulated, feeling the heat come through where the double decks are not installed is remarkable. Think of a Land Rover with a tropical roof.

Quite right XSBank those low revs of Gardners really captured my attention as well. Our 6LXB redlines at about 1800 and I think we will most likely run her around 12-1400 on passages at about 10 knots most of the time. With the CPP we can dial in ideal load and maximize efficiency at pretty much any speed we want so it will be very interesting to see what our real data tells us about fuel burn and overall performance once we launch and get out there testing and exploring with her.

Thanks for sharing the photos of your work on cleaning up the decks, looks like a nasty job. Was there much corrosion or was it more so the deterioration and wear of the non slip material that prompted you to remove them? Dustless blasting would work but not sure they’d let you do that while in the water? Have you tried one of those scrapers on the end of a propane torch as a way of taking off the majority of the glue and tread material? That or some chemical solution might work best if you’d like to keep her in the water as you’re cleaning it all up.

As with you I don’t know of a better solution than the glued on synthetic material. I’ve spent a reasonable amount of time over the past few years traveling to shipyards and yacht builders around the world and have not seen anything new or different on their boats for this. High end super yachts and the like often go with teak on decks, and the company here that we are building with uses faux teak on some of their boats which is really a variation on the “TreadMaster” type material. Painted on non-skid doesn’t work very well for us due to the heat retention of the metal. It is an option and we did this on our previous steel boat with white poly paint and non skid sand. Worked well for non skid and the white kept the deck temps for your feet bearable most of the time in the tropics were we have been mostly the past few years but would still heat up pretty good. The glued on synthetic material seems to cut down the thermal retention and transfer from the metal decks on boats we have been on with this so that seems to be the best option we’ve been able to find.

With your boat being 43 years old and the non skid deck material being of unknown age it is quite possible that it has been on there for over 20 years and maybe we just need to factor that in as the lifespan of this material and plan on needing to replace it every 20 years or so?

You are quite right that keeping the decks bare, no coatings of any kind, is the best solution to preventing corrosion. No water = no corrosion. But I’m not aware of any way of making bare AL sufficiently safe slip wise when walking/working on them. We looked at going with diamond check plate but it has the same heat transfer problems of raw AL and was still not safe enough skid wise for us. Dashew used this on his prototype boat “Wind Horse” and concluded the same thing so they used TreadMaster on all their FPB boats. The key I think as with any coating is the prep and application so our current plan is to be meticulous with this, using the best available adhesive and making sure all the edges are particularly well glued down. Then over the years it would be important to keep an eye on these edges and seal any that show any signs of lifting. So I’m agreeing with you in spirit that nothing would be best but it simply isn’t an option for us until there is either a way to make bare AL sufficiently grippy or there is a new solution all together that comes along. I’m certainly all ears for a better way to create cool non skid AL decks so please keep us posted on your progress with this on your boat.

Our solution for the heat transfer in roofs/ceilings is going to be lots of insulation on all the interior surfaces including all connected structural parts such as ribs, webs, frames, etc. Our previous steel boat was extremely well insulated with spray in foam everywhere and we had extremely little thermal transfer between the exterior and interior of the boat. On one of the refits I repainted the whole hull and decided to go with dark blue for the hull sides and there was no discernable change in interior temperatures even in the very hot areas we cruised for many years in Fiji, Polynesia, RMI, etc. So we are big believers in going overboard on insulation. With the new boat though we are going to bite the bullet and go with EPDM glued to the interior surfaces as it has as close to zero water absorption as you can get of any material we know of. It’s more expensive both to buy and install but insulation is a high priority item so it is smart spending for us.

Thanks again for all your suggestions and sharing your experiences. Hope you will continue to do more.

Wayne
 
I’m loving following this discussion of AL boats. I actually have really liked the looks of the aluminum pleasure boats that I’ve seen. The bare, oxidized metal doesn’t put me off at all.

I do have a question though. Insulation has been mentioned, but I don’t understand how glueing insulated panels to the inside is going to avoid the potential problems of moisture getting between the panels and the AL causing corrosion issues?

Hi Dave, thanks for joining in this discussion.

We share your concern about the potential for trapping water between the hull and the insulation and as with any coating the key is in the prep and application so our approach will be to pay very close attention to the installation of the self adhesive EBDM insulation. No different than paint or foam or any other coating applied directly to AL or steel the key is to have really clean surfaces and no voids. Based on the experiences of others using EPDM for insulation on AL boats, and the manufacturers recommendations, the sequencing is to first apply the EPDM to all the ribs, stringers and other AL components which support the AL surfaces and then to butt the EPDM for the larger surfaces up against this, cutting them slightly oversize so they exert a bit of pressure against the EPDM they are butting up against. All seams are sealed with either a sealant, special tape or a sealing strip applied over the seams. Done properly and carefully this seems to prevent any moisture from being able to get between the AL and the EPDM.

It is also important to not have any fasteners or other things which can act as thermal transfers from the exterior to interior so in places where we will need a way to fasten interior panels we will glue small rectangular plastic blocks directly to the AL plate and the EPDM insulation will be cut around these.

Hope this makes sense and provides some answer to your very astute question. If you do some searches on "EPDM boat insulation" or similar you will find lots of examples and explanations of this in much more detail and with lots of pictures and video. ArmaFlex, ArmaCell and AeroFoam are some of the larger manufacturers of EPDM insulation so you can check on their sites for installation guidelines and examples as well.

Wayne
 
This is how I heat the inside, these are "towel heaters" and they are amazing. Silent (no more of those rotten bus heaters) and radiate like a fireplace. The head can get like a sauna, great when having a shower or...Powered with a Hurricane boiler which is now the noisiest part of the heating system.

Christine has had towel warmers on the Must Have list from the very beginning of our design so she'd delighted to see your mention and recommendation of these here. Once you've experiences bathrooms with towel heaters anywhere, land or sea, there's no going back! Radiant heated floors are also right up there in this department and have not been totally ruled out yet either.

We will have our diesel fired water heater, likely a Kabola right now, in the ER or Workshop which are the furthest aft area of the boat with no direct connection to any living spaces and extremely well insulated both thermally and acoustically so we think we'll be able to have near silent boiler operation.

We will probably still have several small heat exchangers with muffin fans spread throughout the boat for heating most of the interior spaces and they do add some noise but we've had them on our previous boat and wasn't much of an issue. As I said, I'm still researching the option of heated floors which we have had fabulous experiences with in homes ashore but need to see how well the will work on the boat. One factor in favor of the radiator style is that we can double up on these by using them for both heating and cooling through the same circuits and plumbing. Just a matter of valves to switch between heating the water based solution through these with the boiler or cooling it through a chiller. So that is currently our most likely choice for maximum efficiency of systems and least costs for installation and maintenance.

Thanks again for all your great advise! Can never get enough of such first hand knowledge.

Wayne
 
Very kind response - thank you.
 
One factor in favor of the radiator style is that we can double up on these by using them for both heating and cooling through the same circuits and plumbing. Just a matter of valves to switch between heating the water based solution through these with the boiler or cooling it through a chiller.

Just remember that those radiators in cooling mode will sweat condensation, so you'll need some sort of pan to collect the condensate and a way of draining it away to a sump pump.
 
There is a long running discussion about building an AL sail boat on the Cruising Forum that might be of interest to readers of this discussion as well as the OP. The discussion on CF was started by the owners of the new AL boat who have years of live aboard experience on an AL sail boat. There are some very interesting design discussions on that thread that might be of interest. I have gotten quite a number of good ideas from the CF thread.

Bestevaer 49ST - Cruisers & Sailing Forums

On the 122 page CF discussion, which is still going, there is an interesting discourse of what to do with the AL deck. One of the surprising bits of information was the heat transfer of even slightly off white colors. The paint discussion is around this link, Bestevaer 49ST - Page 46 - Cruisers & Sailing Forums.

The Bestevaer boat is all AL and has 75mm of spray insulation and they have not had problems with heat transfer INTO the hull.

Great ideas/information on that discussion.

Later,
Dan
 
There is a long running discussion about building an AL sail boat on the Cruising Forum that might be of interest to readers of this discussion as well as the OP. The discussion on CF was started by the owners of the new AL boat who have years of live aboard experience on an AL sail boat. There are some very interesting design discussions on that thread that might be of interest. I have gotten quite a number of good ideas from the CF thread.

Bestevaer 49ST - Cruisers & Sailing Forums

On the 122 page CF discussion, which is still going, there is an interesting discourse of what to do with the AL deck. One of the surprising bits of information was the heat transfer of even slightly off white colors. The paint discussion is around this link, Bestevaer 49ST - Page 46 - Cruisers & Sailing Forums.

The Bestevaer boat is all AL and has 75mm of spray insulation and they have not had problems with heat transfer INTO the hull.

Great ideas/information on that discussion.

Later,
Dan

Hi Dan, Thanks for alterting me and others in this thread to this other discussion on AL hulls. We too learned how much even the slightest bit of colour adds dramatically to the heat transfer from the sun. I'll spend more time reading over this other discussion and watching for additional ones as well. Always anxious to learn from the experience of others.

Thanks again Dan
 
Just remember that those radiators in cooling mode will sweat condensation, so you'll need some sort of pan to collect the condensate and a way of draining it away to a sump pump.

Thanks Mako, condensation is always a critical consideration throughout the boat and its systems and quite right that the use of radiators to cool will produce a considerable amount in hot humid climates where you need them.

I'm not quite at the point of designing this level of detail for the heating/cooling system but I think designing an effective drainage sytsem in from the get go shouldn't be too difficult.

Appreciate your thoughtful reminder.
Wayne
 
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