New Build - 24m aluminum passagemaker

[Whodgins]

Originally Posted by dhays

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

[Whodgins]

Originally Posted by Xsbank

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

[Xsbank]

Very kind response - thank you.

[Mako]

Originally Posted by Whodgins

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.

[dhays]

Wayne, thanks for the explanation.

[dannc]

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

[Whodgins]

Originally Posted by dannc

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

[Whodgins]

Originally Posted by makobuilders

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